Identify the correct order of steps in the anatomical circui

Identify the correct order of steps in the anatomical circuit for mechanosensory information I - Medullary afferents cross the midline, ascend, and synapse on third-order neurons in the contralateral thalamus. II - First Order Neuron in DRG relays peripheral information into the spinal cord. III - Afferents ascend and synapse on second order-neurons in the ipsilateral medulla. IV - Thalamic afferents synapse on neurons in the primary sensory cortex.

a. I, II, IV, III

b. II, III, I, IV

c. III, II, IV, I

d. I, IV, I, III

Solution

c (III, II,IV,I) is the order of steps.

that is

step1:

Afferents ascend and synapse on second order -neurons in the ipsilateral medulla.

step2:

First order neuron in DRG relays peripheral information into the spinal cord.

step3:

Thalamic afferents ascend synapse on neurons in the primary sensory cortex.

step4:

medillary afferents cross the midline, ascnd, and synapse on third -order neurons in the contralateral thalamus.