Discriminative Touch

Question 1

What carries the mechanoreceptor information from the body?

Answer 1

Dorsal column-medial lemniscal (DC-ML) system

Question 2

Central processes of ____ enter the spinal cord.

Answer 2

1 degree afferents

Question 3

The dorsal columns consists of the ____ and _____, which are composed of axons of mechanoreceptor afferents. They are positioned in the dorsal columns in a ______ order.

Answer 3

cuneate and gracile fasciles; somatotopic

Question 4

The ______ is analogous to the dorsal root (spinal) ganglion in that it contains the cell bodies of sensory neurons

Answer 4

trigeminal ganglion

Question 5

Mechanoreceptive afferent fibers largely synapse in the _____, often referred to as the ______ of the trigeminal nucleus

Answer 5

pontine region; main sensory subnucleus

Question 6

Exceptions are ______, for which the cell bodies are within the mesencephalic trigeminal nucleus, and not the trigeminal ganglion

Answer 6

proprioceptive signals from muscle afferents and PDL afferents

Question 7

The ______ is bringing in afferent signals originating from the body while the _______ is bringing in afferent signals originating from the head.

Answer 7

medial lemniscus; trigeminal lemniscus

Question 8

_____ is the organized map of the body as represented in a particular brain region

Answer 8

somatotopy

Question 9

Neurons in the ___ and ___ project to the primary somatosensory cortex, which lies along the post-central gyrus of the cerebral cortex

Answer 9

VPL and VPM thalamus

Question 10

Body regions are represented along different regions of the post-central gyrus, with the trigeminal signals located most _____, the lower body (sacral dermatomes) represented most ______

Answer 10

laterally; medially

Question 11

____ RFs and _____ mechanoreceptor density allow for greater tactile acuity discrimination

Answer 11

Smaller; higher

Question 12

Injury to peripheral nerves cause changes in the body representation in the cerebral cortex, which change over time; just what changes occur depends upon the ______

Answer 12

degree of nerve regeneration

Question 13

body representation increases as a result of _______

Answer 13

repetitive and prolonged input

Question 14

MECHANORECEPTORS INFORMATION FROM BODY: Central process of primary afferent enter the spinal cord and project to the cerebral cortex via:

Answer 14

dorsal column

Question 15

MECHANORECEPTORS INFORMATION FROM BODY: Secondary neurons projections:

Answer 15

internal arcuate fibers (crossing the midline!), then contralateral medial lemniscus

Question 16

MECHANORECEPTORS INFORMATION FROM BODY: Synapse with tertiary neurons:

Answer 16

ventral posterior lateral (VPL) of the thalamus

Question 17

MECHANORECEPTORS INFORMATION FROM BODY: Tertiary neuron projections:

Answer 17

posterior limb of internal capsule, then post central gyrus (S1 cortex)

Question 18

DISCRIMINATIVE TOUCH: Central processes of primary afferents form root of CN V make connections for: Projections to cerebral cortex:

Answer 18

chief sensory nucleus of V - primary afferents synapse with 2o neurons
contralateral trigeminal lemniscus
ventral posterior medial (VPM) nucleus of thalamus, synapse with 3o neurons
posterior limb of internal capsule
postcentral gyrus (S1 cortex)

Question 19

PROPRIOCEPTION: Central processes of the these CN V cells enter pontine region of the brain stem:

Answer 19

chief sensory nucleus of V - primary afferent synapse with 2o neurons
trigeminothalamic tract
ventral posterior medial (VPM) nucleus of thalamus - synapse with 3o neurons
posterior limb of internal capsule
postcentral gyrus