Test 2 - Lecture 3 (Transmission of Sensory Information) Flashcards Preview

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Flashcards in Test 2 - Lecture 3 (Transmission of Sensory Information) Deck (33)
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1

nerve endings contain stimulus-gated ion channels -> generator potentials

receptive field

2

high density of voltage gated Na+ channels -> threshold to trigger action potentials

trigger zone

3

action potentials propagate along -> transmission to first synapse in the dorsal horn

primary afferent fibers

4

neurotransmission of nervous information occurs via

synaptic relays

5

somatosensory information is transmitted from the periphery to the primary sensory cortices via

multi-synaptic relay

6

presynaptic release of neurotransmitter in response to inputs

decoding

7

postsynaptic response to the released neurotransmitter

recoding

8

the response of each relay neuron is determined from the summation of multiple inputs

integration

9

strengthening or lessening the response of each relay neuron to its inputs via other signals that MODULATE the presynaptic release of neurotransmitter, and the post synaptic response to the neurotransmitter

processing

10

excitatory interneuron __________ synaptic transmission

amplifies

11

inhibitory interneuron _________ synaptic transmission

diminishes

12

________ interneurons provide a structure to "focus attention" upon the central point at which the stimulus intensity is greatest

inhibitory

13

feedforward inhibition and feedback inhibition function to...

allow the brain to more accurately focus attention upon the location and nature of the stronger stimulus

14

hierarchical processing of ascending information through synaptic relays... the peripheral receptors are NOT affected

modulation of non-nociceptive somatosensory information

15

allow specific regions of the cortex to "selectively focus attention" upon one particular source of ascending sensory input, suppressing other "background signals" that would be interpreted as "interfering noise"

descending inhibition

16

ascending signals

dampen out inputs arising from receptive fields that are only weakly stimulated

17

descending signals

allow higher centers within the brainstem and brain to modulate the incoming flow of peripheral somatosensory information

18

hyperalgesia

increased sensitivity to the stimulus

19

analgesia

reduced sensitivity to the stimulus

20

nociceptive A(gamma) and C fibers project to second order neurons located within

lamina I and lamina V of the dorsal horn

21

lamina ____ neurons will receive input from visceral nociceptors in addition to receiving both noxious and non-noxious mechanoreceptors

V

22

C fiber activity determines the activity of the inhibitory interneuron by

uninhibited transmission of the nociceptive input

23

A(beta) fibers determines the activity of the inhibitory interneuron by

inhibiting transmission of the nociceptive input through the relay neuron

24

nociceptive input _____ the gate-control inhibitory interneuron

restrains

25

non-nociceptive mechanoreceptor input _______ the activity of the gate-control inhibitory interneuron

strengthens

26

the extent of interneuronal gating is dependent upon the balance between

nociceptive and non-nociceptive inputs

27

afferent sensory fibers may branch extensively once they enter the spinal cord, to synapse upon numerous interneurons located within the gray matter, to modulate the activity of neurons they synapse upon

theory of analgesia

28

two primary descending pathways originate from

periaqueductal gray matter (serotonergic: serotonin)and locus ceruleus (noradrenergic: norepinephrine)

29

analgesia produced by stimulation of the periaqueductal grey matter of

the midbrain

30

_____ opiods enkephalins, endorphins, and dynorphins activate to produce analgesia

endogenous