Question

The ventral root ganglion of the spinal cord contains cells bodies of the
A. Motor neuron
B. Sensory neuron
C. Both A and B
D. Association neuron

Answer 1

Hint: Neurons are typically classified into three types based on their function. Sensory neurons respond to stimuli such as touch, sound, or light that affect the cells of the sensory organs, and they send signals to the spinal cord or brain. Motor neurons receive signals from the brain and spinal cord to control everything from muscle contractions to glandular output. Interneurons connect neurons to other neurons within the same region of the brain or spinal cord. A group of connected neurons is called a neural circuit. A typical neuron consists of a cell body (soma), dendrites, and a single axon.

Complete answer: Interneurons (also called association neurons) are neurons that connect two brain regions. Interneurons are the central nodes of neural circuits, enabling communication between sensory or motor neurons and the central nervous system (CNS). They play vital roles in reflexes, neuronal oscillations, and neurogenesis in the adult mammalian brain.
-Interneurons can be further broken down into two groups: local interneurons and relay interneurons. Local interneurons have short axons and form circuits with nearby neurons to analyze small pieces of information. Relay interneurons have long axons and connect circuits of neurons in one region of the brain with those in other regions.
The association neurons comprise the central nervous system (brain and spinal cord). Hence, the cell bodies of the association neurons are present in the ventral root or the anterior root of the spinal cord.
Hence, the correct option is (D), i.e., Association neurons.

Note: Interneurons in the CNS are primarily inhibitory, and use the neurotransmitter GABA or glycine. However, excitatory interneurons using glutamate in the CNS also exist, as do interneurons releasing neuromodulators like acetylcholine. Interneuron’s main function is to provide a neural circuit, conducting the flow of signals or information between a sensory neuron and or motor neuron.