Question

State the location of the first order neurons in the posterior column-medial lemniscus pathway and name the fiber tracts through which first order neurons project through the spinal cord. State which tract carries information from the legs and lower trunk and which tract carries information from the upper trunk, arms, and neck. Identify each of these tracts in a schematic or cross-sectional image of the spinal cord.

a) First order neurons are located in the dorsal root ganglia. The fibers project through the dorsal and lateral columns. The dorsal column carries information from the legs and lower trunk, and the lateral column carries information from the upper trunk, arms, and neck. [Image description not provided.]
b) First order neurons are located in the ventral horn. The fibers project through the anterior and posterior columns. The anterior column carries information from the legs and lower trunk, and the posterior column carries information from the upper trunk, arms, and neck. [Image description not provided.]
c) First order neurons are located in the spinal cord gray matter. The fibers project through the lateral and ventral columns. The lateral column carries information from the legs and lower trunk, and the ventral column carries information from the upper trunk, arms, and neck. [Image description not provided.]
d) First order neurons are located in the thalamus. The fibers project through the brainstem. There is no specific division of information between legs, lower trunk, arms, or neck. [Image description not provided.]

Answer 1

The first order neurons in the posterior column-medial lemniscus pathway are located in the dorsal root ganglia. The fibers project through the dorsal and lateral columns in the spinal cord. The dorsal column carries information from the legs and lower trunk, while the lateral column carries information from the upper trunk, arms, and neck.

Step-by-step explanation:

The first order neurons in the posterior column-medial lemniscus pathway are located in the dorsal root ganglia.

The fibers project through the dorsal and lateral columns in the spinal cord. The dorsal column carries information from the legs and lower trunk, while the lateral column carries information from the upper trunk, arms, and neck.

The fiber tracts associated with the first order neurons are the fasciculus gracilis, which carries information from the legs and lower body, and the fasciculus cuneatus, which carries information from the upper body and arms.