Final answer:
The spinothalamic tract is responsible for relaying pain and temperature sensations to the brain. The pathway starts with neurons in the dorsal root ganglion and includes synapses in the spinal cord and thalamus before reaching the cerebral cortex.
Step-by-step explanation:
The spinothalamic tract is responsible for relaying pain and temperature sensations to the brain. This pathway begins with neurons in the dorsal root ganglion, which extend their axons to the dorsal horn of the spinal cord. The second order neurons in the spinothalamic tract pathway have their cell bodies in the spinal cord gray matter and connect to the thalamus.
These neurons then decussate within the spinal cord and ascend to the brain, where they synapse with the third neuron in their respective pathway. The neurons in the thalamus then project their axons to the spinothalamic tract, which synapses in the postcentral gyrus of the cerebral cortex.