Test 2 - Lecture 3 (Transmission of Sensory Information)

Question 1

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

Answer 1

receptive field

Question 2

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

Answer 2

trigger zone

Question 3

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

Answer 3

primary afferent fibers

Question 4

neurotransmission of nervous information occurs via

Answer 4

synaptic relays

Question 5

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

Answer 5

multi-synaptic relay

Question 6

presynaptic release of neurotransmitter in response to inputs

Answer 6

decoding

Question 7

postsynaptic response to the released neurotransmitter

Answer 7

recoding

Question 8

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

Answer 8

integration

Question 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

Answer 9

processing

Question 10

excitatory interneuron __________ synaptic transmission

Answer 10

amplifies

Question 11

inhibitory interneuron _________ synaptic transmission

Answer 11

diminishes

Question 12

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

Answer 12

inhibitory

Question 13

feedforward inhibition and feedback inhibition function to…

Answer 13

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

Question 14

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

Answer 14

modulation of non-nociceptive somatosensory information

Question 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”

Answer 15

descending inhibition

Question 16

ascending signals

Answer 16

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

Question 17

descending signals

Answer 17

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

Question 18

hyperalgesia

Answer 18

increased sensitivity to the stimulus

Question 19

analgesia

Answer 19

reduced sensitivity to the stimulus

Question 20

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

Answer 20

lamina I and lamina V of the dorsal horn

Question 21

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

Answer 21

V

Question 22

C fiber activity determines the activity of the inhibitory interneuron by

Answer 22

uninhibited transmission of the nociceptive input

Question 23

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

Answer 23

inhibiting transmission of the nociceptive input through the relay neuron

Question 24

nociceptive input _____ the gate-control inhibitory interneuron

Answer 24

restrains

Question 25

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

Answer 25

strengthens

Question 26

the extent of interneuronal gating is dependent upon the balance between

Answer 26

nociceptive and non-nociceptive inputs

Question 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

Answer 27

theory of analgesia

Question 28

two primary descending pathways originate from

Answer 28

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

Question 29

analgesia produced by stimulation of the periaqueductal grey matter of

Answer 29

the midbrain

Question 30

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

Answer 30

endogenous

Question 31

_______ opiod morphine activates to produce analgesia

Answer 31

exogenous

Question 32

receptors on the presynaptic terminal of the primary afferent nociceptive fiber (stimulating the enkephalin receptor will hyperpolarize the membrane)

Answer 32

presynaptic inhibition (fewer Ca channels will open, these will remain open for shorter time = reduced or blocked NT release

Question 33

receptors on the postsynaptic membrane (stimulating these opiod receptors will hyperpolarize the resting potential of the postsynaptic membrane)

Answer 33

postsynaptic inhibition (EPSP will be less likely to reach a threshold for stimulating an action potential from the postsynaptic neuron)