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305 Cards in this Set
- Front
- Back
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What are the three most fundamental scientific questions about the human condition? |
1. What is our relationship to the rest of the Universe? 2. What is our relationship to the diversity of life? 3. What is the relationship between our minds and the physical world? |
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Give a simple definition of Consciousness. |
Consciousness is the awareness of our thoughts, perceptions, memories, and feelings. |
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Why do neuroscientists believe that consciousness is a palpable, biological entity? |
Physical and chemical alterations to the brain can profoundly affect consciousness |
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How does the ability to communicate relate to our consciousness? |
The ability to communicate allows us to verbalize thoughts inside our own heads
-> typically an indicator of sentience |
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What sorts of case studies support the claim that our ability to communicate underlies our ability to think and be self-aware? |
Brain Damage patient studies provide valuable evidence to support this claim. -> Split brain patients (corpus callosotomy) |
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When is it necessary to have a Split-brain operation? What surgical procedure is it? |
- When a patient has generalized epileptic seizures that are otherwise untreatable (last resort) - The Corpus Callosum, a broad band of nerve fibers connecting the left and right hemispheres of the brain is cut |
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Which hemisphere of the brain is associated with the ability to communicate (talk/write)? |
The Left Hemisphere. However, in some patients, the right brain has an elementary understanding of number, letters and short statements. |
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Give examples of how Split Brain Patients respond to sight and touch. |
Sight: When patients are shown an image only in the left visual field, they cannot verbalize what they saw Touch: When patients are given a mysterious object to touch with their left hand, but receive no visual cues on the left or right field, they cannot name the object they are touching |
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Why is it that some split brain patients learn to reconcile the function of their two hemispheres? |
Well-practiced bimanual skills can be coordinated at the subcortical level -> Patients are able to smoothly choreograph both hands after practice at a given task Also, the interpreter theory suggests that the left brain has no control over the right's actions, but will make post-hoc justifications for them -> the left-brain constructs narratives to help make sense of things |
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What is your 'Attention'? How does affect, or how is affected by your consciousness? |
The phenomenon of attention is a complex array of neural processes. It occurs when the brain directs more processing power to specific modules. Your consciousness can register this change, and also influence further change to achieve specific goals. |
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How did Charles Darwin 'revolutionize' modern day neuroscience? |
He discovered that all eukaryotic organisms evolved from a common prokaryotic ancestor. Following from this, it could be deduced that the first eukaryotic organism which developed a nervous system (the worm) passed this trait down to all subsequent bilateral organisms, such that all such organisms now have a criss-cross fashioned nervous system.
Moreover, seeing as animals have similar nervous systems, testing on animals other than humans could lead to direct result applicability to humans (for study purposes). |
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What is the Fermi Paradox? |
The Fermi Paradox refers to the apparent contradiction between the high probability of extraterrestrial life, as predicted by the Drake Equation and the, to this point, lack of evidence for such life. |
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In regards to evolution, what is functionalism? |
Functionalism is the evolutionary concept that all characteristics of an organism have developed over the years to serve functions useful to that organism, or they were at least useful in the past.
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Why doesn't a highly similar genome (e.g. chimpanzees and humans) correspond with similar phenotypic manifestations? |
The genome similarity might be high, but this does not show us the gene expression levels. |
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What is the difference in development of monkey vs. human brains? |
Monkey brains -> stop developing after birth Human brains -> born with full set of neurons but size keeps growing (extends processes - dendrites and axons) until adolescence (fully at age 25) |
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What is neoteny? |
Neoteny is when extended youth or prolongation of maturation occurs |
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Why is it often said that an 18 year old doesn't have the same self-control as a 25 year old? |
The pre-frontal cortex of an 18 year old isn't fully myelinated yet, reducing processing time |
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What are the 2 methods behavioral neuroscience uses to explain behavior? |
1.Generalization - The explanation of particular instances of behavior, based on general laws deduced from experimentation (i.e. why are they doing this?) 2. Reduction - The explanation of behavior based off empirical physiological evidence (e.g this molecule binding to this receptor, causes this person to feel sad) |
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Explain Rene Descartes' theory about movement
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Descartes hypothesized that movement in humans is controlled by the pressurized shift in bodily fluids. He purported that the pineal gland, which is submerged individually within the ventricles of the brain, acted as joystick of sorts, causing the movement of fluid around the body. Furthermore, he suggested that the control of the pineal gland was given to the mind, a seperate entity from the physical body. |
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Explain how Descartes' theory of movement was quickly disproved by Luigi Galvani. |
Galvani observed that a dissected frog leg had muscle contractions whenever an electrical signal was passed down it. |
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Where are neurotransmitters synthesized? |
They are synthesized locally in the axon terminal
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Is the amount of neurotransmitter precursor molecule always a determinant in the amount of neurotransmitter produced? |
No, however it is dependent in most cases. They are considered agonists. |
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What is the precursor for Dopmaine? |
L-Dopa |
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Would a drug that inhibits the function of enzymes that package newly synthesized Dopamine molecules in to transporter vesicles be considered an agonist or antagonist? |
It would be considered an antagonist as it ultimately causes less receptor stimulation. |
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Explain the role of calcium in action potentials at the axon terminal. |
Once the AP reaches the axon terminal, voltage-gated calcium channels open at the terminal. Ca2+ (influx) binds to proteins which cause vesicle fusion and subsequent neurotransmitter release in to the synapse and a continuation or inhibition of another AP. |
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Is a drug that inhibits an auto receptor for a neuron, considered an agonist or antagonist for the corresponding neurotransmitter receptor? |
It is typically an agonist as auto receptor usually work to inhibit the further release of neurotransmitter. |
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How does the toxin in the venom of a black widow spider work? |
It works best at the acetycholine neuron (movement). -> recognises vesicle w/ neurotransmitter about to bud off -> binds to protein that causes release and switches the protein -> causes incessant ACh release -> Causes cramping and nausea |
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How does botox work? |
Botox utilises the botulinum toxin which blocks acetycholine receptors (antagonist). This causes tension release in muscles due to paralysis. |
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What is the function of Neostigmine and what disease is it used to treat? |
Neostigmine serves to inhibit the breakdown of acetylcholine in the synapse (agonist). It is used to treat Myasthenia Gravis - an autoimmune breakdown of ACh receptors. -> More ACh around to find the fewer receptors. |
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What is the shared function of both methylphenidate (Ritalin) and cocaine? |
They both block the reuptake of catecholamine neurotransmitters (e.g. dopamine, norepinephrine, epinephrine) |
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In regards to neurotransmitters, what is the effect of Tylenol? |
Tylenol can block the reuptake of cannabinoids |
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What is the shared function of Adderall, Ecstasy and Methamphetamine? |
They both cause the reuptake transporters of catecholamines to flip around (i.e. transporters search for catecholamines within the neuron and pump it out in to the synaptic cleft via non-vesicular release) |
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What are the D1 and D2 Receptors? |
They are both families of dopamine receptors. D1 = Increase in cAMP D2 = Decrease in cAMP |
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What function does an antipsychotic serve? |
It binds to D2 receptors and blocks them from ever becoming active (antagonist) causing dopamines ability to decrease adenlyl cyclase have less of an effect. |
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What is the drawback of using CT scans? |
It utilizes X-rays which can lead to mutation and cancer. |
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How does MRI work? |
1. Put patient in magnetic field 2. Let all protons align themselves w/ respect to the magnetic field 3. Shine radio waves at the spot to be imaged 4. Let radio waves knock proton out of orientation 5. Let proton realign with magnetic field, and release it's own radio wave in doing so 6. Measure radio waves to determine proton density in a particular area |
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How does experimental ablation work? What are the 2 ways in which lesions can be caused? What would a control to this lesion involve? |
Experimental ablation involves the removal of a specific region of the brain, hypothesized to be responsible for behavior of a certain kind. 1. Radiofrequency Lesion -> Stick metal wire near area to be destroyed. Inject low-frequency current, causing wire to heat up and burn off the area
2. Exitotoxic lesion -> Inject glutamate/glutamate receptor agonist (e.g. kainic acid, ibotenic acid or NMDA) that causes increased neuronal activity in specific part of brain -> Cause seizure in that brain area -> Neurons that underwent seizure then undergo apoptosis These can be compared to a control group which have a sham lesion inserted in to the same spot but nothing is burned or injected. |
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What is Brain Stereotaxy and how is it done? |
Brain stereotaxy is the actual surgery done to determine which area of a brain to lesion. It involves the use of a stereotaxic apparatus which clamps the head down and positions the syringe. The injection site is determined by a stereotaxic atlas which gives 3D coordinates to a location, w/ respect to the Bregma, the junction of where the 4 skull plated fuse together. |
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How would one go about destroying all neurons in an area that release a specific neurotransmitter (e.g. dopamine)? |
As all the neurons for different neurotransmitters are intermixed, you can't really destroy a single area. Rather, you design a toxic chemical that is only taken up through a given neurotransmitter reuptake transporter. |
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Why would one implant a cannula in to the brain via stereotaxic surgery? |
A cannula is a hollow tube that would allow for later injection of drugs to influence neural behavior (easier access). E.g. You can later on use the cannula to produce temporary lesions through application of local anaesthetic |
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Explain the histological method we use to view the brain. |
1. Add a fixative (e.g. formaldehyde or paraformaldehyde) causing all protein to cross link. 2. Use a microtome machine to slice the brain in to thin sections 3. Stain with either Nissl (blue dye which stick to nucleic acids) or Cresyl Violet (purple dye which sticks to cell bodies) |
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What is the length of a mitochondria? |
1 micrometre |
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What is the benefit of advanced microscopy over normal electron microscopy? |
Advanced microscopy allows imaging of living, moving tissue |
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When doing an analysis of brain circuitry, what are the 2 approaches you must take? |
1. Retrograde Approach -> Trace the afferent axons -> Where is the information coming from? 2. Anterograde Approach -> Trace the efferent axons -> Where is the information going to? |
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Which of these chemicals is Retrograde Tracer and which is a Anterograde Tracer? 1. Pha-L 2. Fluorogold |
Retrograde = Fluorogold Anterograde = Pha-L |
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What is microdialysis? |
Where a hollow tube is inserted in to the brain inside of which is a dialysis membrane (semi-permeable). A chemist analyses (HPLC) what is absorbed by the membrane before and after a neurological process (e.g. baseline serotonin levels vs. after sex). |
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What is an EEG? What can it do? |
An electroencephalogram. It is a macroelectrode which is inserted in to the brain to detect electrical activity of a single neuron (single-cell recording), a bunch of neurons (multi-unit recording) or recordings of an area (field recording). |
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What IEG is most commonly transcripted in response to increased cellular activity? How would you detect presence of it's transcription in the brain? |
c-Fos -> Create antibody for c-Fos with fluorescence marker |
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If you were trying to trace the level of cellular activity in a specific area of the brain, what type of scan would you use? Explain how this type of scan works. |
You would use a PET (positron emission tomography) scan. Subjects are injected with radioactive molecules (i.e. radioactive L-Dopa, radioactive glucose). These molecules are then taken up by neurons which need them the most, as reflected on the scanner.
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Would you put a rodent subject through a PET scanner to track it's neural activity? |
No, PET scans are very expensive. Rather, they simply inject them with the radioactive material, sacrifice them, and then slice the brain in to slices which they display on photographic paper. This is called autoradiography. |
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What is different between a fMRI scan and an MRI scan? |
An fMRI scan is essentially a sequence of MRI scans done one after another. As the properties of oxygenated and deoxygenated blood is very different, in regards to the reflection of radio waves, you can essentially track the blood flow throughout the brain. |
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What are resting state waves? |
Fluctuations in the presence of oxygenated hemoglobin in different areas of the brain, depending on what person thinks about. These occur even at rest. |
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What are the 3 experimental methods you can stimulate a specific neuron or subset of neurons in the brain? |
1. Electrical Stimulation 2. Chemical Stimulation 3. Optogenic Stimulation |
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How does optogenic manipulation of neurons work? |
The gene encoding channel rhodopsin 2 was isolated from an algae. This channel opens in response to blue light. This is paired with a gene promoter (specificity towards target cells) then delivered to the brain via virus. Hence, when a blue light is shined on these neurons, we get to see what happens as they fire APs. This is hard with humans as it is difficult to get foreign DNA in to humans without causing a horrible immune response. |
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Is the energy of a photon proportional or inversely proportional to its wavelength? |
Inversely proportional (i.e. shorter waves have more energy) |
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What is the visible spectrum wavelength range? |
400nm - 700nm |
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What is the protein involved in photoreception? |
Opsin (GPCR) |
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What is the difference between Opsin and Rhodopsin? |
Rhodopsin is simply an Opsin attached to a retinal. It is only found in Rods. Cones have 3 different types of Opsins - 1 for blue, red and green - sensitive mostly to these respective wavelengths. |
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How is color perceived? |
As light shines on the cones, a specific combination of cones will be activated depending on the color. For example a wavelength of 610 nanometers is outside the range for blue cones, but will activate 13% of green cone opsins and 75% of red cone opsins to create a specific color. |
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1. What happens when all 3 primary colors are added together? 2. What happens when all 3 primary colors subtracted from each other? |
1. You get white 2. You get black |
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What are the 3 numbers used to describe any color, and what do each represent? |
1. Brightness - How much light (from black -> white) 2. Saturation - Equal intensity of all colors? - Which wavelength is dominating? 3. Hue - What wavelength (i.e. color) is it? |
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What is the first membrane that covers the eye called? |
The conjunctiva - it is fused with with eyelids
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What is the Cornea? |
A sheet of clear tissue sitting behind the conjunctiva that just allows light to pass through
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What is the function of the Iris and Pupil? |
Allow more or less light in to the eye |
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What is the purpose of the lens in the eye? |
Focuses incoming light on the the focal point (retina) |
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What is the clear gel that fills the eye called? |
The Vitreous Humor |
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Out of cones and rods, which are more sensitive to light? |
Rods are by far more sensitive to light -> Used for night vision |
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What is the Fovea? What structure is found at a high density here? |
The central region in the retina. There are a lot of photoreceptors here. Cones in particular are found abundantly here. |
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What is found at the corner of your eye? |
Your Blind Spot. There's no photoreceptors here but all the axons and blood vessels can be found. |
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What happens after a photoreceptor is activated by light? |
They pass the information on to bipolar cells which then relay the information over to the ganglion cell layer which send their axons to the thalamus and the visual cortex.
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What are the purpose of horizontal cells in the eye? |
They interconnect adjacent photoreceptors and the outer processes of bipolar cells. |
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What are the purpose of amacrine cells in the eye? |
They interconnect adjacent ganglion cells and the inner processes of bipolar cells. |
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What is the receptive field of a visual neuron? |
The part of your visual space that the neuron responds to. The receptive field has both an ON and OFF part. When light is shone on the ON part, the neuron fires more than usual. When it shines on the OFF, it fires less than usual. |
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What are the 2 kinds of color-sensitive ganglion cells? Why are they arranged this way? |
1. Red-Green 2. Blue-Yellow It allows you to tease apart exactly what you're seeing, and helps in distinguishing edges |
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What is the ratio of photoreceptors to bipolar cells in the fovea? |
1:1 |
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What is the function of the extraocular muscles? |
Attach to the back of the eye via the sclera and allow saccadic movement of the eye. |
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Explain how light is translated into neural signals. |
In the Dark, the photoreceptors have Na+ leak channels which allow them to remain at around -60mV, and they constantly release glutamate. There are inhibitory glutamate receptors so the bipolar cells aren't firing. In the light, opsin dissociates from retinal and activates a G-Protein which causes the weak Na+ leak channels to close, thus hyperpolarizing the cell and stops the release of glutamate. |
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What is the path of visual information past the ganglion cell layer? |
It follows the retina-geniculate-striate pathway. The geniculate or lateral geniculate nucleus (LGN) is part of the thalamus. The striate cortex is synonymous with the primary visual cortex. |
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What is processed in layers 1 & 2 of the lateral geniculate nucleus? What are these layers called? |
These are the magnocellular layers -> transmit all information from the rods |
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What is processed in layers 3-6 of the lateral geniculate nucleus? What are these layers called? |
These are the parvocellular layers -> transmit all information from red and green cones |
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What is processed in the layers in between the lateral geniculate nucleus? What are these layers called? |
These are the koniocellular layers -> transmit all information from blue cones |
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To what shapes is the Striate Cortex most sensitive to? |
Lines in a particular orientation |
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With respect to orientation neurons, explain the difference between: 1. Simple cells 2. Complex cells 3. Hypercomplex cells |
1. Simple cells switch ON and OFF depending on the position of the line 2. Complex cells detect if the line is moving in a certain direction (not what position it is in at a single point) 3. Hypercomplex detect if the line segment with a particular orientation ends at a particular point in the receptive field |
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What is stereopsis? |
Is the perception of depth we have due to retinal disparity -> we overlay the images we see in each eye and our brain uses this to give us depth perception |
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What is the visual association cortex? |
The extrastriate cortex as it is also known surrounds the striate cortex. It is where information from the primary visual cortex gets mapped out individually, according to single visual fields. |
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What are the 2 streams of visual processing in the cerebral cortex? |
1. Dorsal Stream -> Occipital to Parietal -> Encodes 'where' 2. Ventral Stream -> Occipital to Temporal -> Encodes 'what' and 'why' |
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What are the 3 types of glial cells mentioned in lectures? What are their respective functions? |
1. Astrocytes Clean up debris through phagocytosis 2. Oligodendrocytes/Schwaan Cells Create myelin sheaths for axons 3. Microglia Direct immune response to the brain |
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What is the difference between contralateral and ipsilateral? |
Contralateral refers to the other side of the body whereas ipsilateral refers to the same side. |
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What are the 3 layers of meninges from superficial to deep? Which is the thickest? |
1. Dura Mater (thickest) 2. Arachnoid Mater 3. Pia Mater |
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Why is the blood brain barrier referred to as semi-permeable? |
There are no leaky gaps in the capillaries, however there are still transporters which can allow passage of select molecules |
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Name all the ventricles in the brain and mention if they are in the forebrain, midbrain or hindbrain |
1. 2 x Lateral Ventricles (Forebrain) 2. Third Ventricle (Forebrain) 3. Fourth Ventricle (Hindbrain) |
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Is the cerebral aqueduct located in the forebrain, midbrain or hindbrain? |
The midbrain |
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Where is CSF produced? |
The Choroid Plexus |
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What is the turnover rate / half-life of CSF? |
50% is replenished every 3 hours. |
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What are the stem cells that create the brain called? |
The neural progenitor cells |
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What are the function of radial glia in neural development? |
They are the first neurons to form from the neural progenitor cells. They send up a membrane process which acts as a scaffold on which further neurons can use to organize themselves. |
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What is the difference between symmetrical and asymmetrical division of neural progenitor cells? |
Symmetrical = division of 1 npc in to 2 npc Assymetrical = division of 1 npc in to 1 npc + 1 radial glia / neuron |
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Does neurogenesis occur in an adult human brain? |
It can. There is a part of the hippocampus which still has neural progenitor cells. However, 99.9% of the neurons that you are born with stay with you throughout life. |
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If neurogenesis stops occuring after birth, why is it that the human brain continues to grow 10-15 years onwards? |
Although no new neurons are being made, the existing neurons grow in size and make connections with each other. |
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Why is it important to have folds and gyri on the cerebral cortex? |
It increases the surface area of the brain, and the cell bodies of neurons are only found on the surface.
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Is grey matter located on the inside or outside of the brain? |
The outside. |
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What does the brain's longitudinal fissure divide? |
The 2 brain hemispheres |
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What does the brain's central sulcus divide? |
The frontal and parietal lobes |
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What areas of the brain are located immediately on either side of the central sulcus? |
Frontal end = Primary motor cortex Parietal end = Primary somatosensory cortex |
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What does the brain's lateral fissure divide? |
It divides the temporal lobe from the frontal and parietal |
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Is the primary motor cortex the first or last place efferent information to the muscles will go? |
The last place it will go before it leaves the brain |
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What are the areas in cerebral cortex that are not primary sensory/motor regions called? |
They are association cortex -> Perception takes place here, and memory is stored (puts fine details together) |
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What is the neocortex? |
The outer portion of the cerebral cortex - most developed part in humans |
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What are the 3 main components of the Limbic System? What is their general function? |
1. Cingulate Gyrus 2. Hippocampus 3. Amygdala They autonomically invoke emotion based on sensory information received |
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What is the function of the fornix? |
It is a long pathway which connects the hippocampus to the rest of the brain |
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What is the function of the septum? |
The septum relays the information from hippocampus to amygdala |
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What are the inferior and superior colliculi? |
Little bumps found on the tectum in the midbrain |
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What is a 'real' interneuron? |
An interneuron that only sends its axons locally |
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How many cranial nerves are there? What is their general purpose, and which cranial nerve is the exception to this? |
There are 12 cranial nerves. They deliver motor information and receive sensory information from your face. The exception is nerve 10, the vagus nerve, which controls organs within the thoracic and abdominal cavities. |
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What are the 4 main neuromodulators mentioned in class? Why are they called neuromodulators? |
1. Acetylcholine 2. Dopamine 3. Serotonin 4. Noradrenaline In the brain, they are only made by a few neurons which then send their axons to the rest of the brain (modulate huge areas) |
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What are the respective functions of the 4 main neuromodulators? |
1. Acetylcholine -> Attention 2. Dopamine -> Movement and reinforcement 3. Serotonin -> Mood 4. Noradrenaline -> Attention |
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What are neuropeptides and where are they found? |
Little proteins that are packaged in vesicles and stored in the axon terminal of neurons. They are stored further back then the neurotransmitter vesicles meaning there must be a very high influx of Ca2+ (high AP frequency) for them to be released. They are used once then degraded (inefficient). |
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How do lipid-based signalling molecules work? |
A piece of cell membrane (endocannabinoid) from the post-synaptic cell clips itself off and this floats back to the presynaptic cell which is generally inhibited. |
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Is neuropeptide and lipid-based molecule information received through GPCR or Ion Channels? |
GPCR only |
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What is different between heroin, morphine and imodium A-D? |
They are all opiates but heroin is lipid soluble, morphine is less lipid soluble and imodium A-D is no soluble at all. The less soluble drugs remove the reward factor that leads to drug addiction as it takes much longer to get the reward (no link) |
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In general, how do we register sounds? |
Sounds come in the form of waves which cause pressure changes that move the eardrum in and out. |
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What is the approximate frequency of sound that the human ear can register? |
30 - 20,000 Hz
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What are the 3 physical dimensions of sounds? Give a brief explanation of each. |
1. Pitch -> frequency of waves 2. Loudness -> amplitude of waves 3. Timbre -> complexity |
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What is the sequence of anatomical structures of the human that is used to register sound, starting from external to internal? |
1. Pinna 2. Tympanic membrane (eardrum) 3. Ossicles (middle ear bones) 4. Oval window (cochlea) 5. Round window (cochlea) 6. Auditory hair cells (cochlea) |
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Are the outer and inner hair cells of the cochlea both attached to the tectorial membrane? |
No, only the outer hair cells are directly attached to the tectorial membrane but the inner hair cells can still bend back and forth when there is relative movement of the two membranes, causing the fluid within the cochlea to move past them. |
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What are the hair cells of the cochlea connected to? |
Bipolar neurons whose axons bring auditory information to the brain. |
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What does pressure on the oval window due to the ossicles (stapes) cause? |
It puts pressure on the fluid enclosed within the cochlea. As fluid is incompressible, this puts pressure on the round window, causing its expansion. Different frequencies of sound cause the round window to push out in different places. |
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Some people suffer with a disease that causes bone growth over the round window at the ear. What problems would such a disease cause? |
It would cause severe hearing loss given that expansion of the round window is what allows us to perceive the vibrations caused by sound. |
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How are adjacent cilia linked to each other on hair cells? |
They are inked through elastic filaments called tip links at points of attachment know as insertional plaques.
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How do pressure changes within the cochlea cause auditory perception? |
Pressure changes from the fluid causes either stretching or relaxation of the tectorial membrane. The tectorial membrane movement influences the stretching of hair cells directly (outer) or indirectly (inner). Cilia on these hair cells are attached to each other via tip links. These tip links attach at insertional plaques which are single ion channels, which open and close according to the amount of stretch at the tip links. Thus, bending of these cilia in accordance with pressure changes caused by the ossicles can send nerve signals which are registered by the brain. |
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What is the organ of corti? |
The sensory organ on the basiliar membrane of the cochlea that contains the auditory hair cells. |
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Are outer or inner hair cell of more importance in transmitting auditory information to the central nervous system? |
Although they are much more numerous, outer hair cells are not involved as much in transmitting auditory information to the CNS (only 5%). |
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What is the main role of outer hair cells? |
They are involved in altering the mechanical characteristics of the basilar membrane and thus influencing the effects of sound vibrations on the inner hair cells. When stretched, ion channels cause the outer hair cells to contract. Contraction in turn amplify the vibrations of the basilar membrane, increasing sensitivity to sound. |
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What is the "core region" of the brain? |
The primary auditory cortex, located on a gyrus on the dorsal surface of the temporal lobe.
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What are the two streams of the visual association cortex and which are respectively involved in the perception of form and location? |
1. Dorsal Stream
- Form 2. Ventral Stream - Location |
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What are the two streams of the auditory association cortex and which ones are respectively involved in the analysis of complex sounds, and sound localization? |
1. Anterior stream
- Analysis of complex sounds 2. Posterior stream - Sound localization |
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Explain how "place coding" occurs within the cochlea. |
A place code is the system by which information about different frequencies is coded by different locations. In this case, increased distension along the basilar membrane, caused by differing frequencies, causes a place code whereby the brain can then perceive the frequency of sound. |
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At what end of the cochlea do higher frequencies cause more displacement? |
Higher frequencies cause more displacement at the basal end (closer to stapes) of the cochlea. |
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How does the cochlea perceive high frequencies vs. lower frequencies? |
Higher frequencies are registered through place coding whereas lower frequencies are perceived through rate coding (rate of neuron firing). |
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What are overtones? |
The frequency of complex tones that occurs at multiples of the fundamental frequency. |
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What is the fundamental frequency of a sound? |
The lowest, and usually most intense, frequency of a complex sound; most often perceived as the sound's basic pitch. |
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What are the 3 physiological mechanisms by which we can determine the location of a sound source? |
1. Phase differences
- Low frequencies 2. Intensity differences - High frequencies 3. Timbre analysis - Determines height of sound source and whether it is front or back (pinna) |
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What part of the auditory cortex is responsible for distinguishing different identities of sound (what) at once? |
The ventral stream.
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What do the vestibular sacs and semicircular canals of the ear, respectively respond to? |
The vestibular sacs respond to the force of gravity -> inform the brain about the head's orientation The semicircular canals respond to angular acceleration. |
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What is the main purpose of the vestibular system? |
To maintain balance and the head in an upright position. |
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What is amusia? |
The inability to perceive or produce melodic music. |
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What are the 3 anatomical structures of the vestibular system? |
1. Vestibular sacs 2. Semicircular canals 3. Cupula |
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What are the utricle and saccule? |
Vestibular sacs which contain hair cells that experience a shearing force when the otoconia (small crystal of calcium carbonate) move in response to a shift in position of the head. |
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What is the function of the cupula? |
It is a gelatinous mass which is pushed against by the fluid in the semicircular canals when the head is rotated. This causes triggering of receptor potentials in the hair cells located there. |
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What does the somatosensory system provide information on? |
It informs about touch and pressure, both on the surface of the skin and within the body.
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What are the 3 interacting somatosensory systems? |
1. Exteroceptive system -> Cutaneous senses 2. Proprioceptive system -> Location of body 3. Interoceptive system -> Internal conditions |
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What are the 2 types of thermal receptors in the skin? |
1. Cold sensors 2. Warm sensors |
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Where are cold sensors and warmth sensors respectively located? |
Cold Sensors -> just beneath the epidermis Warmth Sensors -> deep in the skin |
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What type of fibres respectively relay the information of cold sensors and warmth sensors? |
Cold Sensors -> Thinly myelinated A-Delta fibers Warmth Sensors -> Unmyelinated C fibers |
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Does localised somatosensory information (e.g. fine touch) ascend the dorsal column ipsilaterally or contralaterally? |
Ipsilaterally. It first synapses at the medulla where the information then crosses to the contralateral side. |
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Does non-localised somatosensory information (e.g. pain or temperature) ascend the dorsal column ipsilaterally or contralaterally? |
It immediately crosses the spinal cord where it has its first synapse and then ascends through the spinothalamic tract. |
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Where does somatosensory information first arrive in the brain, and where does it go from there? |
Medial lemniscus -> Ventral posterior nucleus of the thalamus -> Primary somatosensory cortex |
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What is somatosensory agnosia? |
When you cannot identify objects by touch, but can often draw the object. |
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What is the leading theory behind the cause of phantom limb? |
Confusion in the somatosensory cortices (primary + association) -> brain can't interpret nonsense signals received |
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How do we perceive gustatory information? |
1. Taste molecule binds with receptor 2. Changes membrane permeability causing receptor potentials 3. Different substances bind different receptors to give different tastes |
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Are taste receptors replaced often or very rarely? |
They are replaced often (~10 days) -> constantly exposed to hostile environment |
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What are the 6 different types of taste receptors? |
1. Sourness 2. Sweetness 3. Saltiness 4. Umami (glutamate) 5. Fat 6. Bitterness |
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What feature do almost all odorous compounds have? |
Pretty much all lipid soluble (and often organic in origin) |
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What is the olfactory epithelium? |
The tissue of the nasal sinus that sits on top of the cribiform plate, and contains olfactory receptor cells. |
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How many different types of receptors can a single olfactory cell produce? |
1 |
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What are mitral cells? |
Neurons that receive information from olfactory receptor cells and bring that information to the rest of the brain |
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Where does olfactory information go from the mitral cells? |
Mitral cells -> Glomeruli -> Amygdala -> Limbic Cortex (piriform + entorhinal cortex) |
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Humans have 339 different olfactory receptors but we can recognize up to ten thousand different odorants, why is this? |
Combinatorial processing |
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What is an electromyogram (EMG)? |
A tool used to measure muscle activity |
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What is an electro-oculogram (EOG)? |
A tool used to monitor eye movements |
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What are the 6 main types of EEG signals recorded during sleep? What states of sleep do they correspond to? |
1. Alpha activity -> relaxation 2. Beta activity -> arousal 3. Theta activity -> intermittent drowsiness 4. Delta activity -> deep state 5. Slow-wave activity -> synchronized deep state 6. Rapid eye movement (REM) activity -> desynchronised, no muscle tone |
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What are sleep spindles and K complexes? |
Sleep spindles = short bursts of sleep waves -> 2-5 times/minute K complexes = sudden sharp waveforms (more common in older people) -> 1 time/minutes |
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At what point in sleep is there no longer any skeletal muscle tone? |
During REM sleep.
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How can animals like dolphins appear to never sleep? |
They actually do sleep, but their version of sleep alternates between the two cerebral hemispheres. |
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What is the largest developmental difference in sleeping patterns for humans? |
Infants = ~50% REM sleep Adults = ~25% REM sleep |
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As a general rule, what is the difference between sleeping patterns of large predatory animals in comparison to prey? |
Predator = long, uninterrupted Prey = short, sporadic |
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What is the correlation between sleep and body weight? Why is this? |
There is an inversely proportional relation between weight and hours of sleep per day. This is due to economy of scale -> larger = more efficient |
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What are the 3 main theories explaining why animals sleep? Give a brief description of each. |
1. Energy conservation -> stops unnecessary energy consumption during the night 2. Brian processing -> allows brain to update synaptic connections 3. Restoration -> diffusion of waste products out of the brain (glymphatic system) |
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What is the glymphatic system? |
The waste clearance pathway of the brain. It removes excess proteins and other metabolic waste from the interstitial space in the brain. |
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When does the removal of waste products from the brain occur? |
During sleep only. |
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What is a circadian rhythm? |
The daily change in behaviour and physiological processes that follows a cycle of approximately 24 hours. |
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What happens to the behaviour and physiological processes of animals that are kept in constant darkness or constant dim light? |
They will maintain their circadian rhythms to a large extent but may experience some drifting (23 - 25 hours cycles). |
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Why is light considered a Zeitgeber? |
Regular daily variation in the level of illumination keeps the internal clock adjusted to 24 hours. |
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Where is the internal biological clock located in mice? |
The suprachiastmatic nucleus (SCN) in the hypothalamus |
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What does a lesion of the suprachiastmatic nucleus (SCN) of the hypothalamus cause? |
Disruption of the normal circadian rhythm -> total amount of sleep still the same |
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How do SCN neurons maintain circadian rhythm? |
Two genes create two interlocking feedback loops. Expression of one protein reaching a certain level causes its own inhibition and promotes expression of the other protein. |
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What are advanced and delayed sleep phase syndrome? |
Advanced = mutation of per2 gene causing 4-hour advance in biological clock (sleep at 7pm, wake at 4 am) Delayed = mutation of per3 gene causing opposite delay. |
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Which 5 neurotransmitters in the brain are associated with arousal? |
ACh (dorsal pons, basal forebrain, medial septum) NE (locus coeruleus) Serotonin (raphe nuclei) Histamine (tuberomammillary nucleus) Orexin (lateral hypothalamus) |
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What do the group of neurons in the ventral lateral preoptic area (vlPOA) of the brain control? |
The preoptic area neuron can cause drowsiness and sleep. Lesion of the area causes sleep suppression and insomnia. It inhibits wake-promoting neurons (histamine, serotonin and NE) |
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What kind of system is used to allow the 2 separate states of waking and sleeping? |
A flip-flop system. The sleep promoting region in the vlPOA and the arousal systems mutually inhibit each other. In the ON state, the arousal system is on and the vlPOA is inhibited. In the OFF state, the opposite occurs. Both can't be activated at the same time. |
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What occurs to people with a lack of orexinergic neurons? |
They fall asleep during waking hours (narcolepsy) |
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What is the sleep molecule hypothesis? |
That build up of adenosine during waking hours promotes tiredness and sleep. Adenosine receptors can tonically inhibit specific groups of cholinergic neurons in the brain responsible for arousal. |
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How does coffee promote arousal? |
Caffeine is a powerful blocker of certain adenosine receptors that inhibit cholinergic neurons responsible for arousal. |
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When is acetycholine neuron firing particularly low? |
High during waking and REM sleep Low during slow-wave (deep) sleep |
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What type of sleep patterns do ACh agonists faciliate? |
They facilitate REM sleep
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What do the SLD and vlPAG regions of the brain contain, relevant to sleep? |
SLD = REM-ON neurons
vlPAG = REM-OFF neurons |
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What is narcolepsy? |
A sleep disorder (hereditary autoimmune) characterized by periods of irresistible sleep. Due to orexin neuron death. |
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Where are the cell bodies of orexin neurons found? |
In the lateral hypothalamus. |
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What is REM sleep behaviour disorder? |
A neurological disorder in which a person does not become paralyzed during REM sleep and can thus act out dreams. |
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During which month of gestation does the precursor for one of either male or female sex organs wither away? |
During the 3rd month |
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How do internal and external female sex organs develop? |
Internal = absence of anti-mullerian hormone
External = absence of androgen hormones |
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How do the testes on males develop? |
Y chromosome has Sry gene
-> instructs undifferentiated fetal gonads to form testes |
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What 2 things happen as a result of testes development? |
1. Anti-mullerian hormone release -> stops development of internal female sex organs (mullerian system) 2. Testosterone release -> starts development of internal (wolffian system) and external male sex organs |
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How do the ovaries develop? |
The primordial gonads automatically develop in to ovaries with a lack of Sry gene (Y chromosome). |
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What happens when you don't have 2 X chromosomes and have a bad or non-existent Sry gene? |
X0 = Turner Syndrome XY (defective Sry) = Swyer Syndrome Both result in no gonad development -> no testes = internal & external female sex organs but no puberty |
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What happens when you are an XX individual with an Sry gene translocated on? |
Sry gene overpowers XX -> testes development
Develop in to heterosexual male -> lacking other Y genes so small sterile testes |
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What happens if you are a normal XY individual with non-functional androgen receptors? |
You will develop testes as normal, and anti-mullerian hormones will prevent internal female sex organs from developing. However, you will develop external female genitalia. |
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Is the human brain sexually dimorphic? |
Yes -> The sizes and interconnectivity of specific brain regions vary according to sexual identity |
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What is thought to be a possible biological cause of homosexuality? |
A lack of exposure to androgens during a critical period of development
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What causes dimorphism in sexual behaviour? |
Androgen signalling during development typically dictates their sexual behaviour and preference in later life (i.e. no testosterone or insensitive receptors = female behaviour). |
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What happens when there is prenatal androgenization of genetic females? |
With disorders known as congenital adrenal hyperplasias, adrenal glands secrete an abnormally large amount of androgens -> females have external genitalia masculinization and can be attracted to women |
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Do the following female rats have male or female sexual behavior when grown, if given the following: 1. E + P (fully grown) 2. Testosterone (fully grown) 3. Testosterone (imm. after birth) & E + P (fully grown) 4. Testosterone (imm. after birth) & Testosterone (fully grown) |
1. Female behavior 2. Neither male or female behavior 3. Neither male or female behavior 4. Male behavior |
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What is the difference between the menstrual and estrous cycles? |
The menstrual cycle is what most primates have. -> characterized by mesntruation The estrous cycle is what mammals other than primates have. -> characterized by monthly behavior change (heat) which alters behavior of nearby males |
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Is the ability to mate in higher primates determined by ovarian hormones? |
No, only in estrous females (non-primate mammals)
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What are the 3 effects the release of estradiol, followed by progesterone, have on females? |
1. Increased proceptivity
2. Increased attractiveness 3. Increased receptivity |
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What is the role of kisspeptin in sexual maturation? |
It is a neuropeptide produced by neurons in the arcuate nucleus of the hypothalamus which initiates puberty and maintains reproductive ability by triggering release of GnRH.
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What are the 2 gonadotropic hormones released due to GnRH? |
Follicle stimulating hormone (FSH) and Luteinizing hormone (LH)
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What are estrogens? What is the principal estrogen of humans? |
A class of sex hormones that cause female genitalia maturation, growth of breast tissue, and female physical feature development.
-> Estradiol = principal estrogen |
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What is the Coolidge effect? |
The restorative effect of introducing a new female sex partner to a male that has apparently become "exhausted" by sexual activity. |
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What is the medial preoptic area (MPA) of the brain involved in? |
There is an area within the MPA called the sexually dimorphic nucleus (SDN) that is much larger in males than females and causes male copulatory behavior (erection and ejaculation) |
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How is the MPA area of the brain connected with the motor neurons of the spinal cord involved in copulation? |
They both synapse with the periaqueductal gray matter (PAG) of the midbrain and the nucleus paragigantocellularis (nPGI) of the medulla. |
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What neurotransmitter is involved in the inhibitory connections between neurons of the nPGI and the ejaculatory generator? |
Serotonin -> application of serotonin suppresses ejaculation |
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What is the role of the ventromedial nucleus of hypothalamus (VMH)? |
It plays an essential role in female sexual behavior (lesion = no lordosis, stimulation = sexual behavior) |
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What are the 4 steps of the neural pathway for female sexual behavior? |
1. VMH 2. PAG 3. nPGI 4. Motor neurons |
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What is the role of vasopressin and oxytocin in determining sexual behavior? |
Vasopressin -> higher levels in ventral forebrain = monogamous relationships Oxytocin -> higher levels in cerebral ventricles = pair bonding |
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What is a pheromone? |
A chemical released by one animal that affects behavior or physiology of another animal; usually smelled or tastes |
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What are the 4 potential effects of pheromones? |
1. Lee-Boot Effect - females housed together (no male urine) -> estrous cycles slow and eventually stop 2. Whitten Effect - Synchronization of menstrual/estrous cycles in presence of male urine 3. Vadenbergh Effect - Earlier onset of female puberty in presence of male urine 4. Bruce Effect - Pregnancy termination due to presence of unfamiliar male urine |
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What sensory organ detects pheromones? |
The Vomeronasal Organ (VNO)
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Do women who regularly spend time in presence of males have longer or shorter cycles? |
They tend to have shorter cycles the longer they spend with men. |
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Which region of the forebrain, that is responsible for male sexual behavior, has a large role in the maternal behavior of females? |
The medial preoptic area of the forebrain. |
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How do higher levels of prolactin and oxytocin influence human fathers? |
They are associated with higher levels of paternal instinct.
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Where are the abstract and feeling aspects of emotion respectively processed in the brain? |
Abstract = neocortex Feeling = limbic system (amygdala) |
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What are the 3 response patterns associated with a raw feeling of emotion? |
1. Behavioral component -> muscular movement 2. Autonomic response -> Symp/Para 3. Hormonal response -> Reinforce autonomic |
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What area of the amygdala sends information to the various brain structure which control emotional response? |
The central nucleus |
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What type of emotion is mainly activated in the central nucleus of the amygdala? |
Aversive emotions like fear and anxiety. |
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What type of emotion is mainly activated in the medial nucleus of the amygdala? |
Sexual and aggressive emotions. |
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What is a conditioned emotional response? |
A classically conditioned response that occurs when a neutral stimulus is followed by an aversive stimulus. |
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What part of the brain is responsible for the extinction of a conditioned emotional response (e.g. freezing)? |
The medial prefrontal cortex is related to the extinction of a conditioned emotional response. |
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What is the purpose of the lateral nucleus of the amygdala in emotional response patterns? |
It is where conditioned emotional responses are learned -> sends projections to the basal and central nuclei |
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What is James-Lange's Theory of emotion? |
1. We perceive an emotion-eliciting stimulus 2. We undergo an appropriate set of behavioral and physiological responses (e.g. sweating) 3. Brain receives feedback from changes in the PNS which in turn causes feelings of emotion |
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Are human emotional expressions innate or learned responses? |
They are innate responses -> Blind athletes same -> Different cultures same -> Babies can imitate |
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What happens to people with volitional facial paresis? What is the opposite of volitional facial paresis called? |
They are unable to volutarily control their facial muscles but can change their facial expression when expressing genuine emotion. The opposite of this emotional facial paresis. |
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Is the amygdala involved in the recognition or the volitional expression of emotion? |
It is involved in the recognition of emotion. Patients who undergo a bilateral amygdalectomy can express artificial emotions but cannot recognise the emotions on the face of others. |
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Which hemisphere of the brain plays a more significant role in the recognition of voice and facial expressions of emotion? |
The right hemisphere
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What is the role of the somatosensory cortex in the perception of emotion?
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When we see a facial expression we unconsciously imagine ourselves making that expression
-we try to provide a representation of what an emotion feels like |
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What is a mirror neuron? |
A neuron that fires both when an animal acts and when the animal observes a similar action done by something else. |
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What is the role of the Ventral Prefrontal Cortex in humans? |
The vPFD has inhibitory connections with the amygdala, therefore it can suppress emotional responses in social situations. |
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Do serotonergic neurons play an inhibitory or stimulative role in human aggression? |
They play an inhibitory role |
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What is a satiety mechanism? |
Brain mechanism that causes cessation of hunger or thirst, produced by adequate and available supplies of nutrients or water |
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What is the difference between volumetric and osmometric thirst? |
Volumetric is caused by a low blood volume level whereas osmometric is caused by osmoreceptor detection of hypertonic saline water (osmotic pressure against cell). |
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Describe the steps of the renin angiotensin pathway briefly. |
1. Reduced blood flow to kidneys 2. Kidney production of renin 3. Renin converts angiotensinogen to angiotensin 1 4. 1 is converted to 2 5. 2 causes retention of sodium and water, causes thirst |
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How does angiotensin 2 cause thirst? |
Neurons in the subfornical organ detect presence of angiotensin 2 - excites neural circuits that stimulate thirst |
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What region of the brain contains osmoreceptors that can stimulate osmometric thirst? |
The ateroventral tip of the 3rd ventricle (AV3V) |
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Why does ingestion of water not cause immediate satiation if you have hypertonic interstitial fluid? |
Activity in the AV3V continues as the water takes about 20 minutes to reach the 3rd ventricle. |
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What is the effect of insulin on blood glucose levels? |
It decreases glucose levels by making it into glycogen and it also allows glucose transporters in the body to internalize glucose within cells. |
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What organ of the body detects blood glucose levels? |
The pancreas |
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What peptide hormone is released in response to low blood glucose levels? |
Glucagon -> causes glycogen to glucose conversion |
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What is the role of the peptide hormone ghrelin? What regulates it release? |
It is released by an empty stomach and promotes hunger. Absence of food in duodenum regulates its release from the stomach. |
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Explain the process of a Roux-en-Y Gastric Bypass (RYGB) surgery and what it achieves. |
The size of the stomach is greatly reduced and then connected directly to the jejunum. This bypasses the majority of the stomach and the duodenum. It serves to reduce fat absorption and reduces hunger. |
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What stops people from consuming further food after a meal (short-term satiety)? |
Although stretch receptors in the stomach play a role, it is small. Satiety is mainly given when stomach receptors detect presence of nutrients (glucose, amino acids and fatty acids). CCK is released in to the bloodstream which transmits a satiety signal via the vagus nerve. |
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What is cholecystokinin (CCK)? |
A hormone secreted by the duodenum that provides a satiety signal. It is also involved in gastric motility and can cause the gallbladder to release bile. |
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What is peptide YY3-36 (PYY)? |
A short-term satiety signal that is released by the small intestine in amounts proportional to the calories ingested. |
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If an animal is force-fed so that it become fatter than normal, what happens to its food intake when permitted to regulate it's own food intake? |
It will reduce its food intake |
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How is hunger reduced in the long term? |
Leptin produced proportionately by fat cells causes a negative feedback mechanism which decreases hunger. |
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What are Ob mice? |
Obese + low metabolic rate mice -> due to mutation preventing leptin production |
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In regards to food consumption, what are emergency circuits? |
Neural pathways which are activated when a specific critical need to eat or not eat overrides the energy homeostasis circuitry.
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What are the 2 emergency food circuits?
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1. Glucoprivation 2. Lipoprivation |
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What are the 2 groups of neurons contained within the arcuate nucleus (ARC) of the hypothalamus that are involved in hunger? What activity do each promote/inhibit? |
1. AGRP -> promotes hunger (orexigenic) 2. POMC -> inhibits hunger (anorexigenic) |
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In regards to hunger, what purpose does the paraventricular nucleus (PVN) of the hypothalamus serve? |
The PVN contains oxytocin neurons which can inhibit hunger -> low firing = intense hunger -> excessive firing = normal feeding (can't override other signals) -> therefore involved in emergency feeding |
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In regards to hunger, what happens to patients with Prader-Willi Syndrome? |
They lose the PVN Oxytocin neurons which are involved in the suppression of hunger
-> hungry all the time |
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What are anorexia nervosa and bulimia nervosa? |
Eating disorders
Anorexia = exaggerated concern over weight => compulsive dieting and exercising Bulimia = bouts of excessive hunger and eating followed by forced vomiting |
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What is non-associative learning? |
The phenomena of habituation and sensitization
-> responding differently to a stimulus because you have previously perceived it |
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What is the difference between habituation and sensitization? |
They are both forms of non-associative learning. Habituation = waning of sensitivity due to repeated stimulation Sensitization = increased sensitivity due to repeated stimulation |
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What part of the brain has a particularly high synaptic plasticity? |
The hippocampus |
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What is long-term potentiation (LTP)? |
The long-term and stable increase in strength of the connection between 2 neurons due to high intensity and high frequency repeated stimulation. |
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High frequency potential pulses often produce long-term potentiation whereas the same number of pulses fired at a slower rate can produce long-term depression. Why is this? |
LTP is caused when the postsynaptic neuron is firing at the same time as the synapse is active -> high frequency stimulation means the postsynaptic cell will often be activated |
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Why does firing of a postsynaptic neuron at the same time as synapse activation cause strengthening of the synapse? |
1. Mg2+ ions block NMDA receptors below threshold potential 2. When depolarized and forming an action potential, Mg2+ ions leave the NMDA receptor 3. Allows the pore to open in response to glutamate binding 4. Allows Ca2+ influx 5. CaMKII activated by Ca2+ resulting in intracellular signalling 6. Increase in AMPA receptors which cause EPSPs when glutamate binds |
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What are AMPA receptors? |
Ionotropic glutamate receptors that cause EPSPs when open. They are upregulated in response to CaMKII signalling, thereby strengthening synapses -> memory. |
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What is the role of Nitric Oxide in memory formation? |
NO may be a retrograde messenger which contributes to LTP formation |
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What is associative learning? |
Stimulus-stimulus and stimulus-response learning -> when perceiving a stimulus it either makes you more likely to think of something else or respond in the same way |
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What is Hebb's Rule of Long-Term Potentiation? |
A hypothesis that proposes the cellular basis of learning involves the strengthening of synaptic connections that active when the postsynaptic neuron fires an AP. |
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What are the 4 basic forms of learning? |
1. Relational learning -> declarative memory 2. Perceptual learning -> recognition and categorization 3. Motor learning -> learned motor skills 4. Stimulus-response learning -> classical and instrumental conditioning |
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What part of the brain is involved in classical conditioning? |
The amygdala |
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What is a classically conditioned emotional response? |
One established by pairing a neutral stimulus (e.g. tone) with an aversive stimulus such that whenever the neutral stimulus is applied, it brings up memories of the aversive stimulus. -> Due to hard-wiring of stimuli |
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What is instrumental conditioning? |
Learning that occurs due to reinforcement (positive or negative) -> requires the animal to be able to move / make decisions as to promote learned movement and thought processes |
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What is the role of the basal ganglia in learning? |
They reinforce instrumental conditioning
-> contain ventral tegmental area and nucleus accumbens (dopamine signalling) |
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Are areas of the brain involved in the acquisition of behavioral sequences the same as those involved in automated procedures? |
No. As action sequences get repeated, different circuits within the basal ganglia become involved in action selection and action execution. |
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What is the difference between episodic and semantic memories? |
Episodic memory = personal experiences associated with a time and place Semantic memory = memory of facts and general information (doesn't have to be associated with time / place) |
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Brenda Milner first described the effects of a hippocampus bilateral lesion on the patient HM. What were the results of this lesion? |
- Cured epilepsy - Anterograde amnesia - Graded retrograde amnesia - Brief working memory |
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What is Korsakoff's syndrome? |
Permanent anterograde amnesia caused by brain damage.
Sufferers can still remember past memories. They sometime also suffer from confabulation -> reporting of memories of events that did not take place |
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What is the simplest model of the memory formation process? |
1. Sensory information enters short-term memory
2. Rehearsal keeps it there 3. Eventually enters long-term memory 4. Permanently stored |
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Are short-term or long-term memories stored in the hippocampus? |
Neither. However it functions in short-term memory consolidation. |
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What is memory reconsolidation? |
Memories are reactivated -> enter a labile unstable state -> can be modified and reconsolidated -> events interrupting reconsolidation can cause memory to be lost |
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What part of the brain is responsible for keeping track of and remembering spatial locations (relational learning)? |
The hippocampus
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Rats are released in a Morris Water Maze and tested to see how long it takes for them to find a way out. Based on such experiments, does having a hippocampal lesion affect relational memory more or stimulus-response? |
It affects relational memory more although stimulus-response memory is also impaired.
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How does the size of a mouse's caudate nucleus correspond to its performance in a virtual maze? What about the hippocampus? |
Higher gray matter volume of caudate nucleus = better performance Higher gray matter volume of hippocampus = lower performance |
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What do place cells in the hippocampal formation do? |
They fire when an animal passes a specific place within an enclosure (direction specific). |
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Do the grid cells located deeper within the hippocamus have smaller or larger location-based grids? |
They have larger location-based grids |
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How are semantic memories formed? |
First events are recorded as episodic memories (self-referenced). Over time, semantic information is extracted from the episodic memories. |
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How do the processes of memory encoding and retrieval work? |
Cortical sensory systems (encoding) -> Hippocampus -> (retrieval) Cortical sensory systems The hippocampus merely acts as a hub or node that is capable of reactivating the sensory systems originally used to encode the memory -> Over time, reactivation becomes less dependent on the hippocamus (long-term memory) |
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Which area of the brain is capable of neurogenesis? What does this neurogenesis facilitate? What is a possible downside? |
Neurogenesis constantly happens in the hippocampus of the brain -> improves pattern separation abilities -> neurogenesis often accompanied by apoptosis of older neurons (memory loss) |
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Which of the following are responsible for immediate emotional perception of pain and which for long-term?
Anterior cingulate cortex Prefrontal cortex |
Anterior cingulate = immediate Prefrontal = long-term |
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What would a lesion in area postrema / solitary tract (AP/NST) cause? |
It would cause a lack of glucoprivic and lipoprivic feeding. |
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What are the 2 genes related to obesity in humans? |
1. MC4 2. FTO |
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What are uncoupling proteins (UCP) and what are they used for? |
They convert nutrients in to heat -> helps with weight loss |
