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Flashcards in Test 2 terms Deck (55)
1

plasticity

ability of synaptic function to change depending upon antecedent activity

2

facilitation

rapid increase in amplitude of post-synaptic potentials following a train of stimuli. 2nd EPSP is bigger than the first, etc.

3

depression

causes neurotransmitter release to decline during sustained synaptic activity. This depletes the pool of releasable vesicles.

4

augmentation

increase in the amount of transmitter released from the presynaptic terminal lasting a few seconds.

5

potentiation

increase in the amount of transmitter released from the presynaptic terminal lasting minutes (post tetanic potentiation).

6

associative learning

formation of associations among stimuli and/or repsonses

7

classical conditioning

a neutral stimulus (CS - bell) is paired with a stimulus that elicits a response (US - meat powder)

8

Instrumental (operant) conditioning

an organism learns to associate consequences with its own behavior. delivery of a reinforcing stimulus is contingent upon expression of a designated behavior.

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habituation

reduction in a response to a stimulus that is delivered repeatedly

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dishabituation

recovery of a habituated response due to presentation of another strong stimulus

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sensitization

enhancement of a response produced by presentation of a strong stimulus

12

L7

motor neuron that synapses with the gill muscle, the site of which habituation appears to occur

13

L29

interneuron that releases serotonin in response to the head shock. this activates GPCRs that are linked to CAMP production, which activates PKA which phosphorylates and CLOSES K channels. closing K channels decreases K conductance and prolongs the AP and allows more Ca inside.

14

Long-term potentiation

long lasting enhancement of the strength of stimulated synapses. LTP is input specific, the input only affects the pathway it is associated with. membrane potential of postsynaptic cell determines if LTP will occur. AMPA and NMDA receptors.

15

long-term depression

persistent weakening of synapses based upon recent patterns of activity

16

myosin

long coiled tail and globular head which has ATPase activity. Think filament of muscle.

17

actin

globular, thin filaments of muscle

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tropomyosin

rod shaped, interacts with troponin to hide actin

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troponin

protein complex that associates with tropomyosin to form a barrier to formation of cross-bridges between actin and myosin. when Ca binds the tropomyosin-troponin complex exposes myosin

20

t tubules

invagination of membrane into the sarcoplasmic reticulum that conducts the depolarization (EPP) which triggers the release of Ca

21

tetanus

contraction is sustained without any relaxations

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asynchronous recruitment

to maintain tetanic contractions in a muscle, some motor units are contracting while others relax in order to prevent muscle fatigue and failure

23

gamma motor neurons

neurons that innervate muscle spindles - specialized muscle fibers that sense stretch and help set muscle fiber length

24

alpha motor neurons

neurons that innervate the striated muscle fibers that generate the force of contraction

25

size principle

small units are activated by weak synaptic stimulation, large units require greater synaptic stimulation

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motor unit

each motor neuron innervates multiple muscle fibers in a single muscle

27

motor neuron pool

multiple motor neurons innervate a single muscle

28

gamma bias

basal level of gamma motor neuron activity required to enable muscle spindles to operate at all muscle lengths

29

golgi tendon organ

these are in series with extrafusal muscle fibers, are innervated by group 1b sensory afferents, relatively insensitive to passive stretch but are very sensitive to muscle contraction. this regulates muscle tension with negative feedback pathway.

30

nociceptor

pain receptor, initiates the flexion reflex

31

flexion reflex

withdrawl from a painful stimulus, yet activates the contralateral limb to maintain balance

32

central pattern generators

local spinal cord circuits that control and coordinate complex motor behaviors, such as locomotion and swimming. involves stance and swing phases.

33

vestibular complex

receives information from the vestibular system (balance, equilibrium). rapidly adjusts to stabilize posture.

34

reticular formation

cardiovascular & respiratory control, sensory motor reflexes, eye movements, sleep, arousal, coordination of limb and trunk movements. initiates adjustments to stabilize posture during movement. is modulatory and premotor

35

homunculus model

shows what a man's body would look like if each part grew in proportion to the area of the cortex of the brain concerned with its movement.

36

mirror motor neurons

distinctive class of neurons that discharge both when a monkey executes a motor act and when it observes another individual performing the same or similar motor act.

37

spinal shock

initial period of hypotonia when spinal interneurons are devoid of descending input (after a few days spinal circuits regain significant function)

38

Babinski sign

when dragging a pointy object along the bottom of the foot the toes extend and fan out. indicates damage to corticospinal pathway, and is a potential sign of MS

39

spasticity

increased muscle tone; hyperactive stretch reflexes and clonus (alternating contractions/relaxations in response to muscle stretch)

40

medium spiny neurons

contained within the corpus striatum (caudate and putamen), receives input from cortex, and outputs to neurons in globus pallidus and substantia nigra (pallidum)

41

Parkinson's disease

disease caused by loss of dopaminergic neurons in the substantia nigra. characterized by tremor, slowed motion, rigid muscles, impaired posture and balance, dementia, etc. treated with L-dopa and possibly stem cell therapy

42

Huntington's disease

hereditary, progressive disease that is always fatal. appearance characterized by hyperkinesia and chorea, abnormal movements, dementia, personality disorder. caused by genetic mutation int he gene that produces huntingtin which leads to neuronal cell death. can only treat the symptoms.

43

motor error

the difference between intended and actual movement

44

Purkinje cells

the only output cells of the cerebellar cortex, all of which are inhibitory. receives input from parallel (from as many as 200,000 granule cells) and climbing fibers

45

granule cell

most abundant neuron in the brain, about 200,000 are in contact with 1 purkinje cell via parallel fibers

46

basket cell

has inhibitory input synapse with purkinje cell

47

golgi cell

receive input from mossy fibers and has inhibitory output on granule cells

48

stellate cell

modifies purkinje cell dendritic output via an inhibitory synaps

49

excitatory loop

made up of mossy and climbing fibers that drive activation of neurons in the deep cerebellar nuclei (DCN)

50

inhibitory loop

purkinje cells respond to excitatory input from the climbing fibers and granule cells and invert this signal onto the deep cerebellar nuclei

51

climbing fiber

provides input to the purkinje cell, 1:1 ration, may have 1000 synapses with each cell. AP in climbing fiber gives strong EPSP in purkinje cell

52

mossy fiber

synapses onto granule cells, axons form parallel fibers which contact many purkinje cells

53

parallel fiber

synapses with purkinje cells, is made up of granule cell fibers

54

saccades

conjugate eye movements that change the point of foveal fixation

55

GABAergic

inhibitory synapses that open Cl channels, how outputs from basal ganglia performs inhibition