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85 Cards in this Set
- Front
- Back
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Brain Hypothesis
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All behavior can be explained through the functioning of the nervous system (of which the brain is the controlling and organizing element)
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Neuron Hypothesis
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The neuron is the fundamental unit of information processing in the nervous system. Neurons receive, process (integrate), and transmit information
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Neural Plasticity
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Neurons and the networks they are part of are capable of experience- dependent change
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Embodiment
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The mind and psychological processes in general are a product of the interaction of the nervous system and the body of which it is a part
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Cartesian Dualism
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The philosophical belief that behavior is generated and controlled by a non-physical mind (intellect, soul) acting through the physical body (brain included). Thus, two separate entities.
-> For Descartes- the point of interaction was the pineal body and ventricular system -Dualism gives rise to the mind-body problem: How does an immaterial substance move a physical body? |
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Darwin and Materialism
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-living organisms evolve through the mechanism of natural selection
-individual variations within a species that are advantageous to survival lead to increased reproduction -all organisms are related through common descent -b/c all animals are related, all brains must be related |
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Localizationism vs. Holism
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Are specific behavioral attributes located in discrete brain regions or in the whole brain?
Localizationism- Phinneas Gage, brain lesions, "Tan"- had stroke- could understand language but could not produce- Paul Broca found damage in the frontal cortex of the left hemisphere Holism- behavior returns to normal after lesion |
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Glial Cell
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Support cells for neural function and repair
Function: -structural support for brain and neural cells -insulate axons: -> oligodendrocytes (CNS), Schwann cells (PNS) -> make a fatty substance called myelin- wraps around axons and insulates them leading to faster neural transmission Astrocytes: -regulation of extracellular environment --> help absorb excess neurotransmitter and replace chemicals that neurotransmitters need- also regulation of neurotransmission -Nutrition of neurons --> high metabolic demands Microglia: immune system function |
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Neuron
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Fundamental units of information processing in the nervous system ~100 billion
-neurons receive, integrate, and transmit information electrochemically (within neuron= electrical, b/w neurons = chemical) -3 categories: sensory neuron, interneuron, and motor neuron -3 types: multipolar neuron, bipolar neuron, and unipolar neuron |
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Peripheral Nervous System
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Somatic= spinal nerves (sensory and motor componetns), cranial nerves
Autonomic= sympathetic and parasympathetic Enteric- located in the gastrointestinal tract, sometimes considered part of autonomic |
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Sensory Neuron
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-receive input via receptors from the external and internal world and transmit to the CNS
i.e.bipolar neuron (retina), somatosensory neuron (skin, muscle) |
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Interneuron
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-receive input from other neurons to send output to other neurons
i.e. association cell (thalamus), pyramidal cell (cortex), purkinje cell (cerebellum) |
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Motor Neurons
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-transmit signals from neurons in the CNS (brain and spinal cord) to muscles to control body movements and organ function
-located in the spinal cord |
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Synapse
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the zone where 2 neurons come in close contact and signals are exchanged
-also where information is stored (memory = a series of synaptic connections) -surrounded by astrocytes -pre-synaptic component (axon terminal), synaptic cleft, post-synaptic component (surface of the dendrite or cell body) |
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Dendritic spine
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an outgrowth along the dendrite of a neuron- effectively increase the surface area of the dendrites- allow for extra synaptic contacts-may be rapidly altered by experience- such as training or exposure to sensory stimuli- form of neural plasticity
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axon hillock
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a cone-shaped area from which the axon originates out of the cell body
= neuron's integration zone -packed with voltage-gated Na+ channels that sense changes in voltage (threshold) |
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Afferent nerve
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-carries info from the sensory receptors in the skin to the brain
-going towards a particular reference structure- i.e. sensory neuron |
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Efferent nerve
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-carries info from the brain to neurons controlling leg muscle, causing a response
-going away from a particular reference structure i.e. motor neurons |
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Bell-Magendie Law
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sensory info from periphery enters the spinal cord through dorsal roots (sensory neuron), synapses, and sends neurons back through the ventral roots (motor neurons)
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Spinal nerves
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8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal
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Autonomic nervous system
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Sympathetic branch: responding to threatening/motivating stimuli
-acetylcholine and norepi -dilates pupils, relaxes airways, accelerates heartbeat, inhibits digestion, relaxes bladder, supresses reproductive function Parasympathetic branch: rest/repose -acetylcholine -constricts pupils, slow heartbeat, constricts airways etc. *Together they contribute to homeostasis* |
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Dura Mater
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The outermost of the 3 meninges that surround the brain and spinal cord
-covers the contours of the skull |
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Arachnoid Layer
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The thin covering (one of the 3 meninges) of the brain that lies between the dura and pia mater
-space within the arachnoid is filled with CSF (subarachnoid space) |
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Pia Mater
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The innermost of the 3 meninges that surround the brain and spinal cord
-covers the contours of the brain |
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Gyrus vs. Sulcus
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G: A ridged or raised portion of a convoluted brain surface
S: A furrow of a convoluted brain surface *Sulci separate Gyri |
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Sylvian (Lateral) Fissure
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deep fissure that demarcates the temporal lobe
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Central sulcus
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a fissure that divides the frontal lobe from the parietal lobw
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Frontal Lobe
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Most anterior portion of the cerebral cortex
= motor function (precentral gyrus), planning, sequencing |
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Parietal Lobe
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Large regions of cortex lying b/w the frontal and occipital lobes of each cerebral hemisphere
= sense of touch (postcentral gyrus), pain, body senses |
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Occipital Lobe
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Large regions of cortex covering much of the posterior part of each cerebral hemisphere
= vision (receive and process info from the eyes) |
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Temporal Lobe
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Large lateral cortical regions of each cerebral hemisphere, continuous with the parietal lobes posteriorly, and separated from the front lobe by the Sylvian fissure
= mainly hearing, but also taste and smell, and non-sensory function = memory and learning |
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Corpus Callosum
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bundle of axons that crosses the midline and allows communication b/w the right and left cerebral hemispheres
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Ventricles
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Series of chambers filled with CSF
-Lateral Ventricle: a complexely shaped lateral portion of the ventricular system within each hemisphere of the brain- extends into all 4 lobes- CSF produced here Third Ventricle: The midline ventricle that conducts CSF from the lateral to 4th vent (lies anterior to the cerebellum) |
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Cerebral Spinal Fluid
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-shock absorber for the brain
-provides a medium for exchange of materials, including nutrients, b/w blood vessels and brain tissue -Flows from lateral vent-> 3rd vent-> 4th vent-> 3 small openings below cerebellum to circulate over the outer surface of brain and spinal cord-> absorbed back into the circ. system through large veins beneath the top of the skull |
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Basal Ganglia
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A group of forebrain nuclei (caudate nucleus, globus pallidus, putamen) found deep within the cerebral hemispheres
-receive input from the substantia nigra (in the midbrain) -very important in motor control (habit and skill learning- motor memory) |
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Limbic System
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Amgydala- group of nuceli in the medial anterior part of temporal lobe- emotional regulation
Hippocampus (and fornix)- a medial temporal lobe structure, important in learning and memory Cingulate gyrus: a cortical portion of the limbic system found in the frontal and parietal midline- implicated in the direction of attention Olfactory bulb- anterior basal structure that receives smell inputs from nasal cavity Mammillary bodies- pair of nuclei found at the base of the brain- involved w/ processing recognition memory and olfactory sensations |
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Forebrain
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contains the cerebral hemispheres, the thalamus, and hypothalamus
Divided into the Telencephalon (Isocortex, Basal Ganglia, and Limbic System) and Diencephalon (Thalamus, Hypothalamus, and Epithalamus (pituitary, pineal body, and habenula)) |
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Midbrain (Mesencephalon)
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Superior colliculi- process visual information
Inferior colliculi- process auditory info (together, known as the tectum) Substantia nigra- part of the basal ganglia, contains neurons that release dopamine into the caudate -also contains cell bodies that send axons out to form cranial nerves |
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Hindbrain
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Metencephalon (Cerebellum and Pons)
Myelencephalon (Medulla) |
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Diencephalon
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Thalamus: complex cluster of nuclei that act as way stations to the cerebral cortex. Almost all sensory info enters the thal.- where cortical cells process the info and neurons send it to the cortex
Hypothalamus: hunger, thirst, temperature regulation, reproductive behaviors (survival oriented behaviors)- controls the pituitary gland |
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Metencephalon
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Cerebellum: packed w/ neurons, fine motor control, balance
Pons: lump of fibers on ventral surface of the brain stem, connects spinal cord and forebrain- intimately connected w/ the cerebellum, arousal and respiration |
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Myelencephalon
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Medulla: cluster of neurons- send signals to the heart
-respiratory, cardiac, autonomic function (vital, involuntary function) -tissue damage here is often fatal |
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Pathways of Neural Transmission
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-groups of nerve fibers may be called "bundles" or "fasiculae"
-> named according to the regions through which they pass or by their points of origin/ termination (i.e. medial forebrain bundle) |
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Brain-Blood Supply
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-fed by internal carotid artery -enters the skull and branches into anterior (forebrain) and middle cerebral (limbic system, brain stem) arteries- which supply blood to the large regions of the cerebral hemispheres
-posterior cerebral artery- occipital lobe Circle of Willis: a structure at the base of the brain that is formed by the joining of the carotid and basilar arteries- allows blood to flow in both directions -most likely to have stroke in middle cerebral artery b/c most direct from internal carotid artery-> leads to visual impairment, lose ability to produce speech (Broca's aphasia), memory deficits |
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Gradient
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A term describing the relative densities of a particular substance between spacial locations
Conc: high-> low conc Charge: ions will tend to diffuse towards areas of opposite charge and away from areas of like charge = "electrostatic pressure" |
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Diffusion
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Spontaneous spread of molecules of a particular substance from areas of high concentration to areas of low concentration until conc. is uniform
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Polarization
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separation of charge and solute concentration across the membrane
Potential = magnitude of the difference in distribution of charge Voltage = measure of electrical potential |
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Electrical Current
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flow of charged particles from a region of high conc -> low conc
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Plasma Membrane
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Acts as an insulator- separates charged particles
-Semi-permeable: lipid bilayer and ion channels |
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Ion Channels
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A protein or complex of protein that can form a pore or hole in the cell membrane and allow charged particles to pass
-Voltage-Gated: opened by changes in the membrane potential Ligand-gated: opened by the binding or effect of a chemical-usually a neurotransmitter |
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Resting Membrane Potential
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-The difference in the electrical potential across the plasma membrane of an unstimulated neuron
-Inside of a cell is ~60-70 mV more negative than the outside Why? -membrane = very permeable to K+, much less permeable to other ions and virtually impermeable to proteins, which tend to have a negative charge -K+ will flow into the cell due to neg. charged proteins, however will stop due to conc. gradient- usually around -60mV = Equilibrium Potential -Na+/K+ pump: 3 Na+ out/ 2 K+ in -50% glucose metab. powers this pump -driven by ATP -needed to maintain resting membrane potential More K+/ Protein in the cell, More Na+/ Ca2+/Cl- outside the cell |
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Graded Potential
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Change in membrane potential that spreads passively across the cell membrane and is initiated at a particular site
-due to ion influx and decreases in strength w/ time and distance -can be a passive hyperpol or depol- but always comes back to resting potential -Most likely to find at the input zone (cell body and dendrites)- causes by ligand-gated channels opening- neurotransmitter binds, confor. change- and then it opens |
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Action Potential
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A large, very rapid reversal in the polarity of the cell membrane. Occurs when voltage-gated Na+ channels open
-Threshold = -40 mV -AP propagates down the axon to the synaptic terminal and does not lose strength = nerve impulse -reverses polarity of the membrane -Most likely to find at the integration zone/ output zone -at the axon hillock- lots of voltage-gated Na+ channels open at -40mV |
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Receptor
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A protein or protein complex that selectively binds and is regulated by a specific molecule or class or molecules
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Ionotropic
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A receptor that includes an integral ion channel that is gated by the binding of its ligand -> very specific and acts very rapidly (open and closes quickly)
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Metabotropic
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A receptor that does not contain an integral ion channel. It acts via intracellular biochemical processes to regulate other receptors or intracellular elements -> activated more slowly, longer lasting, and more widespread action
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Ligand
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A chemical that binds selectively to a particular receptor
-Endogenous- naturally occurring in the body -i.e. ACh, glutamate -Exogenous- Not made in the body- i.e. nicotine binds to ACh receptor |
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Agonist
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A chemical (exogenous) that binds to a neurotransmitter receptor and produces the same effect as the endogenous ligand (i.e. nicotine)
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Antagonist
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A chemical that binds to a neurotransmitter and prevents and agonist from having an effect
i.e. mecamylamine binds to ACh receptor and prevents ACh from having an effect -can be competitive or noncompetitive- transmitter can still bind but does not activate Pufferfish gland- contains tetrodotoxin (TTX)- binds to Na+ channels and prevents APs from occuring, black widow toxin does the same |
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Post-Synaptic Potential (PSP)
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Change in the membrane potential of the post-synaptic cell, caused by the actions of the pre synaptic cell
-cause by the activation of ligand-gated ion channels -produce graded potentials -> Excitatory (EPSP)- increases likelihood that AP will occur due to NA+ influx-> depolarization -excitatory synapse= round pre-synaptic vesicles and thick post-synaptic vesicles -> Inhibitory (IPSP): decreases likelihood that AP will occur due to Cl- influx -> hyperpol. Inhibitory synapse = flattened vesicles and no post-synaptic density |
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Temporal Summation
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Summation of IPSPs and EPSPs arriving at different points in time
-closer together in time = more of an effect |
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Spatial Summation
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Summation of IPSPs and EPSPs arriving at different locations on the post-synaptic neuron
-inputs closer to axon hillock have more of an effect on cell excitability and AP generation -in our body- inputs closest to cell body/axon hillock tend to be inhibitory |
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Myleinated vs. Unmyelinated axons
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Unmyelinated: regularly spaced and more continuously distributed
-slow conduction of AP (1-10m/s), channels can move in membrane -less energy and saves space (tend to be thin and slow- some Na+ leakage) -does not go backward Myelinated Axon: rapid, saltatory conduction, clustered, faster- 100 m/s -broken by unmyelinated areas: Nodes of Ranvier -> densely clustered v-gated Na+ and K+ channels -this is where you see the AP- as if it jumps from one to the other = salutary or "jumping" conduction -faster b/c myelin keeps Na+ from leaking out, increase diffusive pressure-> wider diameter- conducts more quickly -M.S.-effects myelin-slower transmission and sensory motor difficulties |
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At the Synapse...
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1. Invasion of pre-synaptic terminal by the AP
2. Activation of V-gated Ca2+ channels- neuromodulation properties-> bind to proteins on NT vesicles 3. Neurotransmitter vesicles dock with the membrane and release contents into the synaptic cleft (after being activated by the Ca2+ influx)- only need 3-4 molecules 4. Neurotransmitter diffusion across the synapse and binding to post-synaptic receptors 5. EPSP or IPSP across cell membrane (post-synaptic effect)- depends on the type of NT released and type of receptor protein Termination of Signal: 6. Enzymeatic Degradion of NT -i.e. acetylcholinesterase breaks down ACh- if this is blocked- paralyzed respiratory system and suffocates due to muscular paralysis 7. Reuptake -taking neurotransmitter back up by transport protein -also reuptake on glial cells (astrocytes) which is then transported back to the presynaptic cell 8. Inhibition of Release (feedback inhibition) -autoreceptors -> make it less likely to release NT if excess NT in synapse NEED TERMINATION -excitotoxicity = synapse being excited to death due to too many EPSPs |
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Neural integration and circuits
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Also- neural chain- like knee-jerk reflex- neurons attached linearly
Convergence: Sensory info from retinal receptors cells-> bipolar neuron-> retinal ganglion Divergence: Retinal Ganglion-> Thalamic Cell-> multiple cortical cells in the brain |
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The Patellar Reflex
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-Excitation and Inhibition in simple circuit
- Stimulus of muscle stretch receptor sends signal to spinal cord causing excitation of extensor motor neuron but inhibition of flexor motor neuron causing lower leg kick |
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Classification of Neurotransmitters: Action/Function
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Excitation: EPSP
- Glutamate, aspartate Inhibition: IPSP - GABA, glycine Modulation -acetylcholine, dopamine, serotonin, opioids -can have effects on their own, but also act to heighten or reduce the effects excitatory or inhibitory NTs -> effect depends on receptor type |
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Classification of Neurotransmitters: Chemical Structure
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Small Molecules
-Ester: Acteylcholine -Amine: Dopamine, norepi, serotinon Amino Acid: Glutamate, aspartate, glycine, GABA Steroid Hormones: -Estrogen, DHEA Peptides: -Opioids, Neurohypopyseals- ADH and oxytocin Gasses -Nitric Oxide, Carbon monoxide |
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NMDA receptor
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-ionotropic glutamate receptor
-lets Ca2+ and Na+ in -gated only when lots of glu is released- needs a lot of stimulation! (AMPA and Kainate open first) -blocked by Mg2+ -Depolarization (due to Na+ influx from AMPA and Kainate) -lifts Mg2+ blockade and Ca2+ enters -Ca2+ influx causes addition of more AMPA receptors -> becomes easier to excite -mechanism for synapses to store more info (memory) -Doubley-gated!- both voltage and ligand gated |
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Acetylcholine (ACh)
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Cell bodies: Midbrain-> cerebellum, pons, medulla
Basal Forebrain-> cortex and hippocampus -associated with arousal, sleep cycles, attention, and memory |
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Dopamine (DA)
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Cell bodies: Midbrain-> Cortex (forebrain) and hippocampus (limbic system)
Substantia nigra-> basal ganglia -associated with movement, motivation, memory, reward? |
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Norepinephrine (noradrenaline)
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cell bodies: locus coeruleus-> hippocampus, basal ganglia, cortex
scatting in pons-> cerebellum and spinal cord -associated with attention, cortical arousal, and memory |
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Serotonin (5-HT)
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Cell bodies: Mid-brain-> thalamus, hypothalamus, basal ganglia
Raphe nuclei (in pons)-> cerebellum, spinal cord -associated with sleep cycles, arousal, and mood |
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Forms of Chemical Communication
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Neurocrine communication- local, brief release of neurotransmitter (pre-post-synaptic)
= classic neurotransmission Endocrine- effect on distant tissues (through bloodstream) -also autocrine and paracrine |
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Principles of Hormone Action
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1. Hormone action is gradual
2. Hormones modulate the intensity or probability of evoked behaviors 3. Hormone release is regulated by environmental factors 4. A given hormone can multiple effects on diverse tissues. Specific behaviors may be regulated by more than one hormone. 5. Hormones are produced in small amounts and secreted in bursts. 6. Hormone levels often vary rhythmically over the course of the day.- circadian/ biological rhythms- diff. from neurotransmission! 7. Hormones interact in their effects 8. Hormones affect only cells that have receptors for the particular hormone- similar to neurotransmission *not under voluntary control- more autonomic* |
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Classes of Hormones
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Peptides
-ACTH, insulin, oxytocin, vasopressin, GnRH Amines: -Epinephrine, thyroid hormones, melatonin Steroids: Estrogens, Androgens, glucocorticoids, minealcorticoids |
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Hormone Receptors
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Protein hormone action: 2nd messenger, faster
Steroid hormone action: receptors in the nucleus b/c lipid soluble- leads to new protein production, slower |
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Pineal Gland
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Reproductive maturation and bodily rhythms
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Hormone Regulation
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-negative feed back w/ hypothalamus and pituitary
-also autocrine feedback, target cell feedback (on specific endocrine cell), and brain regulation |
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Anterior Pituitary
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Adenohypophysis
-releasing hormones from the hypothalamus travels to the anterior pituitary through capillaries to cause release of hormones |
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Posterior Pituitary
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Cluster of axons in hypothalamus that extend into posterior pituitary and cause release of hormones
-oxytocin- uterine contractions, nursing, pair bonding -vasopressin |
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commisure
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group of fibers that cross from one cerebral hemisphere to another
-corpus collosum= largest of the commisures |
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Scientific Materialism
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-Science is materialistic: It does not believe in a disembodied spirit world. Science is a-religious, but not anti-religious.
-Scientists believe that the universe is orderly, and that phenomena are governed and controlled by a set of natural laws that are the same everywhere in the universe. -Behavioral neuroscience treats behavior as a topic that is a product of, and subject to, natural laws. -Science is empirical: We can discover these laws, or relationships, through careful observation and experimentation. -Empiricism: The acquisition of knowledge through experience, observation and experimentation. |
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How scientific materialism is different from earlier philosophical approaches
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Hippocrates- no empiricism/experimentation/ experimental laws
Da Vinic- did dissections- so experimentation Dualism- no natural laws Darwin- a-religious, and deductive, no experimentation |
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Brain Organization and Hierarchy
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Modular: there are discrete brain areas that appear to be where certain specific forms of cognition occur
-> synesthetic individuals integrate various modules (i.e. visual and olfactory areas) Interconnected: like synthesthetic individuals- integrate various modules Distributed: modules are distributed throughout the brain |
