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194 Cards in this Set
- Front
- Back
- 3rd side (hint)
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What is lateral inhibition? |
The reduction of activity in one neuron by activity in neighboring neurons. Essentially, it is the retina's way of sharpening constrast to emphasize the borders of objects |
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How does lateral inhibition work? |
- Light comes in and stimulates one receptor which activate other cells - These receptors activate other cells (bipolar and horizontal) - The horizontal cell inhibits the bipolar cell causing graded potentials - Strong inhibition in the area and less in neighboring cells (certain degree of inhibition because you are activating horizontal cells |
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Give an example of how lateral inhibition works |
Light hits the retina and activates cells 6-10. these cells get less inhibition and therefore are more highly active. Cells 5 and 11 get the least activation; they get no light AND spill over inhibition |
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What is happening on the Hermann Grid? |
- Grey dots occur in the middle of the plus sign - This happens because lateral inhibition makes the center seem darker - At the center points, you are getting cell stimulation from all four sides of the square - Less inhibition in the lines because you only get inhibition from the top and bottom of the black lines |
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What is the Receptive field? |
The part of the visual field that either excites or inhibits a cell |
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Discuss what happens in the fovea pertaining to photoreceptors |
They connect to a bipolar cell; several of the bipolar cells then connect to a ganglion cell. This ganglion is responsible for all of the photoreceptors which makes a combines receptive field |
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What happens in an on-center/off-surround receptive field of a bipolar cell? |
When light shines on the center, it activates the bipolar cell. when light shines on the surrounds, it deactivates the bipolar cell |
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What happens in on-surround/off-center receptive fields of a bipolar cell? |
When light shines on the surround, it activates the bipolar cell. When light shines on the center, it deactivates |
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What is the most prevalent cell in the retina? |
P cells (90%) - they are heavily located in the retina |
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Discuss some important facts about M cells |
- 5% - They detect large, low-contrast objects and movement - No response to color - Located mostly in periphery - Respond quickly due to the fact that they pick up movement - Large size and receptive field |
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Discuss some important facts about P cells |
- Provide detailed info about motionless objects, including color - Red-green response - Small size and receptive field size - Does not respond to movement well |
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Discuss some important facts about K cells |
- 5% - Provide information about color - Blue-yellow - Small size and receptive field size - Poor response to movement |
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What percentage of the axons from ganglion cells go to the superior colliculus to control eye and head movements? |
10% |
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What is the Primary Geniculastriate Pathway? |
- Where most of axons from the ganglion cells go - Connects in LGN of thalamus through the optic radiations to striate cortex |
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What layers connect to M, K and P cells in the LGN? |
M - Magnocellular layers K - Koniocellular P - Parvocellular |
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What is also known as area V1? |
Primary visual cortex |
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Discuss the pathway from LGN to V1 to V2 |
- V1 receives info from LGN and is responsible for first stage of visual processing - V2 receives info from V1, processes info further and sends it to other areas |
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What is blindsight? |
Damage in V1 that can lead to an ability to respond to visual stimuli that people do not report seeing. There are two possible reasons for this: 1) small islands of healthy tissue remain within otherwise damaged cortex and not large enough to provide conscious perception or 2) thalamus sneds visual input to several other brain areas outside V1 and other areas strengthen enough to produce certain kinds of experience despite lack of conscious visual perception |
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Can you still process vision even with damage to v1? |
YES due to connections with LGN |
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What can happen BESIDES blindsight if you damage area V1? |
You lose conscious perception and your ability to experience visual imagery. Conscious space then becomes verbal-conceptual |
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What is area v2 also known as? |
Secondary visual cortex. It responds to lines and edges but some respond selectively to circles, right angle lines or complex patterns as well as textures |
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Which parts of the striate cortex are relevant? |
4 forms the eniculate nucleus 3, 5 and 6 output to different parts of the brain |
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What are cortical modules? |
They detect features of different orientation in the visual field. Some columns are responsible for individual eyes and some for both |
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What are the 3 types of cells in the visual cortex? |
Simple cells (on/off cells- vertical lines - responds to stimulus in one location) Complex cells (large receptive field - vertical lines - responds equally throughout large area) End-stopped/hypercomplex cells (detect edges) - these respond to a bar of light with a specific orientation |
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What are feature detectors? |
Neurons whose response indicate the presence of a particular feature or stimuli |
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What are the 3 visual pathways in the cerebral cortex (cortical pathway)? |
- Mostly parvocellular neuron pathway sensitive to details of shape - Mostly magnocellular neuron pathway responds to movement - Mixed pathway sensitive to brightness and color |
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Describe the where pathway |
- spreads from dorsal V1 to parietal lobe - process spatial layout of outside world such as location, distance, relative position, position in egocentric space and motion - also can be thought of as the how pathway because of importance in visually guided movements |
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Describe the what pathway |
- perceive and recognize shape orientation, size, objects, faces and text - also relates to the ventral system - visual info in ventral stream terminates in medial temporal lobe, hippocampus and amygdala and is used for visual recognition and memory and emotional content - can do things like see where objects are - dorsal route processes visual info |
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What area is responsible for color consistency, color perception and visual attention? |
V4. Damage to V4 leads to cortical color blindness and loss of color constancy |
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What is shape consistency? |
the ability to recognize an object's shape despite changes in direction or size |
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What does the inferior temporal neurons do? |
ignore changes in size and direction |
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What is visual agnosia? |
The inability to recognize object by sight despite having intact visual pathways. It is caused by damage to the temporal cortex. Patients can recognize objects by touch and can describe thei functions |
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What is prosopagnosia? |
The inability to recognize faces. It occurs after damage to the fusiform gyrus of the inferior temporal cortex |
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What is apperceptive agnosia? |
Cannot copy drawings of objects |
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What is associative agnosia? |
Copying and matching remains intact, however people have trouble drawing objects from memory |
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What is optic ataxia? |
Not agnosic, but they have difficulty locating objects in space and reaching appropriately |
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How many lobes are included in motion? |
All four lobes of the cortex |
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What is the middle-temporal cortex? (V5/MT) |
- activates by a stimulus moving in a particular direction - acceleration, deceleration and specific speed (experience of seeing motion) - images that imply movement - receive info from magnocellular path - enable you to distinguish between the results of eye movements and the result of object movement |
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What does the Dorsal part of the medial superior temporal cortex respond to? (MST) |
when visual stimuli expand or contract |
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What does the ventral part of MST respond to? |
- represents object movement relative to background - both when objects moves or background moves |
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What is motion blindness? |
the inability to determine the direction, speed and whether objects are moving. It is likely caused by damage in the MT. Some people are blind except for the ability to detect which direction something is moving; usually area MT gets some visual input despite significant damage to area V1 |
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How long does it take for a newborn to gain face recognition? What is their facial preference? |
2 days; preference for a right-side-up face |
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What is the habituation paradigm? |
Showing something to a baby and the longer they look at it, the more meaningful they find the stimulus. They tend to look more at faces than objects |
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Why are critical periods important to vision? |
- early lack of simulation of one eye leads to synapses in the visual cortex becoming gradually unresponsive to input from that eye (due to synaptic pruning) - However, if you have a lack of stimulation to both eyes, cortical responses become sluggish but do not cause blindness - early exposure to limited array of pattern leads to nearly all of visual cortex cells become responsive to only that pattern |
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What is stereoscopic depth perception? |
Brain compares slightly different inputs from the two eyes. This allows judgment of depth. It relies on retinal disparity or the discrepancy between what the left and right eye sees |
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What shape is your eye if you are nearsighted? |
Myopia |
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What shape is your eye if you are nearsighted? |
Hyperopia |
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What are the 3 types of colorblindness? How is it transferred? |
- Transferred on the X chromosome so there is more of a chance it will occur in males 1) Protanopia: Confuse red and green; red cones contain green opsin 2) Deuteranopia: Also confuse red and green; green cones contain red opsin 3) Tritanopia: Extremely rare type not on X chromosome that occurs in males and females; see the world in green and red as you lack blue cones in the retina |
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What is amplitude? What is frequency? What is timbre? |
A: Intensity, perceived as loudness F: Pitch T: quality or uniqueness (you can tell different sounds apart) |
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What is linked to action potentials? |
Movement of hair cells |
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What regulates neurotransmitters released by the hair cells? |
The movement of the cilia |
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How is sound transferred to the Basilar Membrane? |
1) Ossicles transfer vibrations from the tympanic membrane to the oval window 2) Movement of oval window creates waves in the perilymph within the vestibular canal 3) The waves push the basilar membrane up and down 4) Waves travel back along the lympanic canal from the apex to the round window 5) The waves push the round window in and out |
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What is Place Theory? |
Each area along the basilar membrane has hair cells sensitive to only one specific frequency of sound wave. Each frequency activates the hair cells at one place along basilar membrane and nervous system distinguishes among frequencies based on which neurons respond |
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What is frequency theory? |
The basilar membrane vibrates in synchrony with the sound and causes auditory nerve axons to produce action potentials at the same frequency (ex - a sound at 50 Hz would prouce 50 actions per second in the auditory nerve) |
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What is the inferior temporal cortex? |
Portion of the cortex where neurons are highly sensitive to complex aspects of the shape of visual stimuli within very large receptive fields. It responds to meaningful objects and responds to what the viewer perceives |
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What does the parahippocampal cortex respond to? |
Pictures of places and not strongly to anything else |
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What does the Fusiform gyrus (inferior temporal cortex) respond strongly to? |
Faces over anything else, especially in the right hemisphere |
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What are parts of the brain involved in face recognition? |
Parts of inferior occipital cortex amygdala, parts of temporal cortex (fusiform gyrus, rigth hemisphere) |
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What does the ability to recognize faces correlate with? |
The strength of the connections between the occipital face area and fusiform gyrus |
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What are saccades? |
voluntary eye movements |
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How long does it take for neural activity and blood flow in MT and part of parietal cortex to decrease before the eye movement and remain suppressed during the movement? |
75 milliseconds |
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What is the volley principle? |
auditory nerve as a whole produces volleys of impulses (for sounds up to 4000 Hz) |
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How are low and high frequency sounds best explaied? |
Low: Frequency theory - basilar membrane vibrates in synchrony with wave (and each generates one action potential) thus frequency is coded by firing rate and loudness by number of neurons High: Place theory - neurons can't fire as fast as the waves come; neurons might fire every other or third wave |
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What is the route of the auditory impulses from the receptors in the ear to the auditory cortex? |
- cochlear nucleus receives input from ipsilateral ear only - all lateral stages have input originating from both ears - auditory nerve connects up to cochlea - cochlear nucleus to inferior colliculus to auditory cortex |
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What is area A1 also known as? |
Primary auditory cortex |
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What is the function of the primary auditory cortex? |
destination for most information from the auditory system, located in the superior temporal cortex. It is important for auditory imagery |
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Each hemisphere receives most of its information from the _____ ear |
opposite |
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Where are the "what" and "where" pathways located for the auditory system? |
What - anterior temporal cortex Where - posterior temporal cortex and parietal cortex |
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What happens if you damage area A1? |
- can lead to motion deafness: can't detect source of moving sound - does not necessarily cause deafness unless damage extends to subcortical areas |
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What kind of map does the auditory cortex provide? What is it? |
Tonotopic - organized so that cells in each area respond mainly to tones of a particular frequency. Neurons are arranged in a gradient with low-frequency times at one end and cells responding to high-frequency tines at the other end |
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What is a benefit of sound localization? |
Sound reaches the ears at different times, so you can tell where a sound is coming from with a sudden onset |
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What is the benefit of a sound shadow? |
Sound reaching the closer ear arrive sooner as well as louder because the head produces a sound shadow. When sound hits your head, it absorbs some of the sound and can figure out where it comes from and how loud it is |
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What does phase difference do? |
Provides cues to sound location for localizing sounds with low frequencies. Every sound can be represented by a wave. The more out of phase the waves, the farther the sound source is from the body's midline |
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What are some benefits of echolocation? |
- used to locate objects when vision isn't good - animals use it to look for food - find out what is in front or behind you |
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Discuss echolocation in blind people |
- some can use it to pin point objects locations with precision - learn to send clicks from their mouth - Click send sound waves which bounces off objects and figure out where objects are as some of the sound waves come back |
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Discuss Mel Goodale's echolocator research |
- Participants were either good at echolocation or control participants - put in fMRI scanner - if you could use echolocation, you use primary visual cortex to do an analysis of sound that gives them properties similar to vision (object location) |
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What causes conductive/middle ear deafness? How can this be corrected? |
Occurs if bones of middle ear fail to transmit sound wave properly to the cochlea. It is caused by disease, tumors or infection. It can be corrected by surgery or hearing aids that amplify the stimulus |
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What do hearing aids do? |
Amplify the sound. They will create more vibrations |
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What is nerve or inner-ear deafness? |
Results from damage to the cochlea, the hair cells or the auditory nerve. Can vary in degree and be confined to one part of the cochlea. Can be inherited or caused by prenatal problems |
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What is Tinnitus? |
A frequent or constant ringing in the ears. It is experienced by many people with nerve deafness and sometimes occurs after damage to the cochlea; axons representing other part of the body innervate parts of the brain previously responsive to sound |
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What is the vestibular sense? |
Detects the position and the movement of the head. It directs compensatory movements of the eye and helps to maintain balance. As you move, the system senses head movements and sends messages to eyes to remain fixed to compensate for head movement |
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What is the saccule and utricle? |
Register angle of head and linear acceleration. Apart of the vestibular sense. Contain otoliths that move, causing hair cells to bend. It contains a jelly substance that moves back and forth which activates hair cells. When head tilts in different directions, they push against different sets of hair cells and excite them |
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What cranial nerve has action potentials as a result of movement of hair cells? |
8th |
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What are semicircular canals? |
Control rotational movements of the head |
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What is the somatosensory system? What are some parts? |
refers to system responsible for the sensation of the body and its movements. It includes discriminative touch, deep pressure, temperature, pain and itch |
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What are the 3 forms of touch receptors? |
1) Simple bare neuron ending 2) elaborated neuron ending 3) bare ending surrounded by non-neural cells that modify its function |
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what is a pacinian corpsule? |
Onion-like outer structure resists gradual or constant pressure but responds to sudden or vibrating stimuli. Apart of the touch system |
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What are the 7 types of touch receptors? |
1) Free nerve ending (myelinated or thinly myelinated) - near base of hairs and elsewhere in skin. responds to pain, warmth and cold 2) Hair-follicle - hair-covered skin. Responds to movement of hairs 3) Meissner's corpuscules - hairless areas. Responds to sudden displacement of skin; low-frequency vibration 4) Pacinian corpuscules - Both hairy and hairless skin. Responds to sudden displacement of skin, high-frequency vibration 5) Merkel's disks - Hairy/hairless skin. Responds to tangential forces across skin 6) Ruffini endings - both hairy and hairless skin. Responds to stretch of skin 7) Krause end bulbs - mostly or entirely hairless areas, perhaps including genitals. Unsure what they respond to |
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Which part of the body has the largest two point discrimination threshold? |
Calf |
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Information from touch receptors in the head enters the ______ through the ________ |
CNS; Cranial Nerves |
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Information from receptors below the head enter the _____ and travel through ______ to the brain |
spinal cord; 31 spinal nerves (each connects to dermatome) |
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What is a dermatome? |
Refers to the skin area connected to or innervated by a single sensory spinal nerve. Sensory information entering the spinal cord travel in well-defined and distinct pathways (touch pathway is distinct from pain path) |
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From the medulla to cerebral cortex, both touch and pain are represented on the ____ side of the brain |
contralateral |
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In the spinal cord, info from one side of the body travels on _____ side for touch and _____ side for pain |
Ipsilateral; contralateral |
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Where is sonmatosensory information sent in the thalamus? |
Ventral posterior and intralaminar nuclei |
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What are some important thalamus parts and what are their functions? |
LGN - vision Medial geniculate nucleus - auditory info Intralaminar nuclei - process touch and pain Medial Dorsal Nucleus - has to do with emotion |
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What are the areas of the somatosensory cortex? What do they respond to? |
1: texture 2: shape and size 3a: responds to movement of joints, tendons and muscles 3b: size, shape and texture of objects |
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What is pain? Why do we have pain receptors? |
The experience evoked by a harmful stimulus, directs our attention and holds it. If we did not have pain receptors, we would not be aware we were hurting ourselves |
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What are alpha-delta fibers? What are C fibers? |
AD: pain and temperature receptors of the skin; free nerve endings C: pain, temperature and itch receptors of the skin; free nerve endings and not myelinated |
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What does mild pain trigger the release of? what does stronger pain trigger the release of? |
Glutimate; glutimate and substance P |
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What does the somatosensory cortex respond to? |
Painful stimuli, memories of pain, cues associated with pain |
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What parts of the brain are involved with emotional evaluation? |
central nuclei, amygdala, hippocampus, prefrontal cortex, cingulate cortex |
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You don't have to experience the _____ aspects of pain when you are having stimulation of pain receptors. |
emotional |
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What are opioid mechanisms? |
Systems that are sensitive to opiate drugs and similar chemicals. Activating these blocks release of substance P in spinal cord and in the periaqueductal grey of the midbrain |
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What are endorphins? |
Group of chemicals that attach to the same brain receptors as morphine. Cells that release these attach to opiate receptors. They are also released in long-lasting pain |
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What is a placebo? |
A drug or other procedure with no pharmacological effect, although it has a psychological effect |
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What is a cannabinoid? |
Block pain in the periphery of body (Not in CNS) |
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Why might you increase your sensitivity to pain? |
- Damage or inflamed tissue releases chemicals that increase the number of sodium gates (histamine, nerve growth factor) - certain receptors become potentiated after painful stimuli (become better at sending pain) - more likely to experience sensitivity or chronic pain |
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What are endogenous circannual rhythms? |
Internal mechanisms that operate on an annual or yearly cycle (such as birds - migratory patterns) |
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What are endogenous circadian rhythms? |
Internal mechanisms that operate on an ~24 hour cycle. This includes waking and sleeping, eating and drinking, body temperature, urination and secretion of hormones |
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Who is more likely to be a night owl? who is more likely to be a lark? |
NO: Young people L: older people |
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Your body wants to be _____ at night |
cool |
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When does cortisol peak in the ay? |
Highest in the morning; leads to wakefulness |
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What part of the brain can be damaged due to stress? |
hippocampus |
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What is a free-running rhythm? |
Rhythm that occurs when no stimuli resets it. When there is no external cue, human circadian rhythms can run slightly longer than 24 hours. |
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What is a zeitgeber? |
any stimulus or external cue that resets the circadian rhythms. One of the most important ones is light, but also exercise, noise, meals, etc. Social stimuli are not good zeitgebers, unless they induce exercise |
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What is jet lag? what are the two phases of jet lag |
Disruption of the circadian rhythms due to crossing time zones. Phase advance happens when you travel east and is harder to adjust to. Phase delay happens when you are travelling east to west and is easier to adjust to |
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What is the Suprachiasmatic nucleus (SCN)? |
- part of hypothalamus - located above ooptic chaism - main control center of circadian rhythms - damage can lead to less consistent body rhythms |
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How does light reset the SCN? |
through a small branch of the optic nerve called the retinhypothalamic path. Light travels from retina to SCN where ganglion cells with photopigment melanopsin respond directly to light without input from rods and cones (also called third pathway) |
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What are the 2 types of genes in the SCN? |
Period (PER) and Timeless (TIM) Light affects a chemical that breaks down TIM and mutations in the PER gene can create odd circadian rhythms |
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What do both PER and TIM have a concentration of? |
mRNA (functions like a clock). early in the morning, it starts in a low concentration |
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What is the pineal gland? Why is it important? |
It is an endocrine gland located poterior to the thalamus. It secretes melatonin, a hormone that increases sleepiness usually secreted 2-3 hours before bedtime. It also helps to reset the biological clock through its effects on receptors in the SCN |
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What is sleep? |
A state that the brain actively produces. It is characterize by a moderate decrease in brain activity and decreased response to stimuli |
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What is the function of an EEG? |
Allowed researchers to discover that there are various stages of sleep |
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What is a polysomnograph? |
Combination of EEG and eye-movement records |
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what are alpha waves a sign of? |
relaxation |
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Discuss stage 1 of sleep |
- sleep has just begin - EEG dominated by irregular, jagged, low voltage waves |
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Discuss stage 2 of sleep |
characterized by - sleep spindles: 12 to 14 Hz waves during a burst that lasts at least half a second - K-complex: a sharp high-amplitude negative wave followed by a smaller, slower positive wave - temporary inhibition of neural firing - back and forth activity between thalamus and cortex |
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Discuss stage 3 and 4 |
- Slow wave sleep (SWS) - EEG recording of slow, large amplitude wave - slow heart rate, breathing rate and brain activity - synchrony in brain |
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Discuss REM sleep |
- periods of rapid eye movement - EEG waves are irregular, low-voltage and fast indicating high neuronal activity (light sleep) - postural muscles of the body are more relaxed than other stages (deep sleep) - activity increase in pons and limbic system - decreased activity in most cortex's - increase in neuron activity
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What is the order of sleep cycles? |
1, 2, 3, 4, 3, 2, 1, REM |
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how often does the sleep cycle repeat? |
90 minutes |
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What are animal habits influenced by? |
Amount of time devoted to looking for food, extent to which they are safe from predators while they sleep, energy needs |
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As your age increases, REM sleep ____ and NREM sleep ____ |
decreases, increases |
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What is the range of hearing for most adults? |
15/20 - 20,000 Hz |
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What structures form the outer ear? |
Pinna - flesh attached to head that helps us locate the sound |
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What structures does the middle ear consist of? |
- Tympanic membrane: eardrum; vibrate at same frequency as the sound waves that strike it; connects to 3 tiny bones - Oval window: membrane of the inner ear |
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What structures does the inner ear consist of? |
- cochlea - Hair cells |
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What is the current theory regarding sound (freq/place) |
- modification of both |
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What is amusa? |
Tone deafness (4% of people) |
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Do most cells have a preferred tone? |
YES - gradient of areas responsive to lower tones up to areas responsive to higher and higher tones |
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Why might you have hearing problems despite having hearing aids? |
- brain areas responsible for language comprehension become less active - hard to focus attention when you hear everything loud - delayed responses of auditory cortex |
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Discuss the pain-sensitive path in the brain |
1) ventral posterior nucleus of thalamus then to somatosensory cortex (painful stimuli, memories of pain and signals of impending pain) |
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Why are the opioid mechanisms important? |
Shows that opiates act on the nervous system rather than the injured tissue, as well as implying nervous system has its own type of chemicals |
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What is Gate Theory> |
Spinal cord neurons that receive messages from pain receptors also receive input from touch receptors and from axons descending from the brain. These other inputs can close the "gates" for the pain messages - and they do so partially by releasing endorphins |
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How does Capsaicin work? |
uses a burning sensation which decreases the pain |
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What are the 2 kinds of itch? |
1) Mild tissue damage (skin healing after a cut) 2) contact with certain plants (cowhage) |
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What kind of light helps to reset circadian rhythms best? |
short wavelength (bluish) |
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What is a coma? |
Extended period of unconsciousness caused by head trauma, stroke or disease |
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What is a vegetative state? |
alternate between periods of sleep and moderate arousal, although during more aroused state, person shows no awareness of surroundings and no purposeful behavior |
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What is a minimally conscious state? |
occasional, brief periods of purposeful actions and a limited amount of speech comprehension. Step up from vegetative state |
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What is brain dead? |
Condition with no sign of brain activity and no response to any stimulus |
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What is the recticular formation? |
Structure that extends from the medulla into the forebrain; axons from this go into brain/spinal cord and those in the spinal cord form part of the medial tract of motor control |
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What is the pontomesencephalon? |
In the recticular formation; contributes to cortical arousal. Receives input from many sensory systems and generate spontaneous activity of their own. Releases acetylcholine and glutimate |
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What is the Locus Coeruelus? |
Small structure in the pons usually inactive, especially during sleep but emits bursts of impulses in response to meaningful events, especially those that produce emotional arousal |
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What does histamine enhance? |
arousal and alertness throughout the brain |
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During sleep, neurons in thalamus become _____ |
hyperpolarized |
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What is sleep apnea? |
Impaired ability to breathe while sleeping; awaken and gasp for breath |
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What is narcolepsy? |
Frequent periods of sleepiness through the day. Characterized be sleep attacks, occasional cataplexy, sleep paralysis and hypnagogic hallucinations |
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What is Periodic limb movement disorder? |
Move around vigorously during REM periods, acting out their dreams |
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What are Night Terrors? |
Experience of intense anxiety from which a person awakes screaming in terror |
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What is binocular input? |
Stimulation in both eyes. If one eye is deprived of fine tuning, it results in weakened response, but both eyes will be responsive still although sluggish |
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What is strabismus? |
"Lazy eye"; condition in which he eyes do not point in the same direction. Can be corrected with lazy eye therapy |
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What is astigmatism? |
Blurring of vision for lines in one direction caused by an asymmetric curvature of the eyes |
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When does stage 3/4 vs. REM sleep occur? |
Stage 3/4 tends to occur mostly early at night, whereas later on you spend more time in REM sleep |
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What are animal's sleep habits influenced by? |
- amount of time devoted to looking for food - extent to which they are same from predators while they sleep - energy needs |
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How much of sleep time is spent in REM? |
1/5 |
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What are some functions of REM sleep? |
- brain may eliminate unnecessary connections in areas - Learned motor skills may be consolidated - Shake eyeballs to provide oxygen to corneas |
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What are Pons-geniculate-occipital waves? (PGO) |
- Neural wave of activity that starts in the Pons, then in LGN, thin in occipital cortex - Occurs mostly during REM - each PGO is coupled with an eye movement - Constant amount of PGO waves every day |
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Discuss the importance of sleep: Conservation of energy |
- Decrease in body temperature of about 1-2 degrees in mammals - decrease in muscle activity - increase during food shortages |
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Discuss the importance of sleep: Restoration |
- Proteins rebuild in the brain - energy replenished - can lead to impaired concentration, irritability, hallucinations |
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What does caffeine do? |
Blocks adenozyme building so you experience wakefulness |
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Discuss the importance of sleep: Memory and learning enhancement |
- You get learning and memory enhancements when you sleep - Sleep deprivation hurts memory - The more stage 2 sleep you get, the more you improve in sequence scores - increases creativity - involves activity of hippocampus during sleep |
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What is the activation-synthesis hypothesis? |
Dreams are brain's attempt to make sense of info reaching it. It begins with spontaneous activity in the pons which activates many parts of the cortex. The cortex synthesizes a story from the pattern of activation. Pons input usually activates amygdala |
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What is the clinico-anatomical hypothesis? |
Dreams are similar to thinking, just under unusual circumstances. Dreams begin with arousing stimuli that are generated within the brain. This stimulation is combined with recent memories. We use the frontal cortex to monitor our thoughts and make unified conscious experience rational. During sleep, these 2 areas are low in activation so therefore the brain is not censored and there is no info from the outside world, and therefore you can have odd dreams |
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What is Lucid Dreaming? |
Become aware of dreaming while dreaming. It occurs primarily in REM sleep and occurs with an activation of the frontal lobe. Hallucinations occur because there is no input from primary visual cortex and no censorship from prefrontal cortex |
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What is insomnia? |
Inability to sleep. Caused by noise, stress, pain or diseases such as epilepsy or parkinson's. Dependence on sleeping pills and shifts in the circadian rhythms can also result in insomnia |
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What is narcolepsy? |
Frequent periods of sleepiness |
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What is sleep apnea? |
Inability to breathe while sleeping for a prolonged period of time. Consequences include sleepiness during the day, impaired attention. Causes can include genetics, hormones, old age, obesity |
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What is periodic limb movement disorder? |
Involuntary arm and/or leg movements occuring primarily during NREM sleep |
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What is REM behavior disorder? |
Movement during REM sleep; acting out dreams. can lead to injury |
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absolute/perfect pitch
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immediately know frequency.no mid ground.kids music class&genetic.seen in tonal language(asian)
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sound wave |
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two types of tone
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pure:1 frequency. complex:many frequencies
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localized sound:Time Arrival
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Difference in arrival time at 2 ears indicate where obj is to localize sound wave onset if frequency/noise is sudden.
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sound localized:Sound Shadow
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:sound closer to ears louder if 2000-3000hz/high frequency.cause:wavelength shorter than head
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sound localized:Phase Difference
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where ears are in sound wave peak/trough difference.~1500Hz in human.wave reach 2 ears in phase are localized as from directly in front/behind hearer.more out of phase waves are,farther sound source is from body’s midline. Phase difference b/w ears give cues to sound location for localizing sounds w low frequencies
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cochlea
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snail shape.has vestibular system,oval window,basilar membrane& tympanic canal
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3 fluid fill tunnels
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in cross section:scala vestibule,media&tympani
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how many types of pinnae
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5
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role of ossicles:3 bones
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ossicles:3 tiny bones:hammer:malleus,anvil:incus,stirrup:stapes(20x bigger after:make oval window vibrate scala vistibule)hydraulic pump:wave form forceful vibration to go to/pressure oval window
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oval/round window
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:inner ear membrane move pure cochlear fluid(detect movement:10-10m:atom width).
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basilar membrane:shape&function
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hair cell w different properties(by position)resonate to different sound.base/stiff: by oval window.cochlea meet stirrup.if high frequency sound(~20,000hz).apex/floppy:if low sound(~600hz)
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3 semicircular canal:function/what only
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jelly substance(endolymph)line w&bend/trigger hair cell if head move:detect rotate/angle. |
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saccule&utricle
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otoliths(Ca carbonate particle)move w hair cell.detect liner acceleration,head position relative to ground.direct compensate eye movement for balance |
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