Final answer:
The gracile and cuneate fasciculi are somatosensory pathways that transmit sensory information from the lower and upper limbs respectively. They terminate in specific nuclei in the medulla, and their axons continue to ascend the brain stem and terminate in the thalamus. From there, they synapse with the third neuron and project to the postcentral gyrus of the cerebral cortex for processing.
Step-by-step explanation:
The gracile and cuneate fasciculi are anatomical terms related to somatosensory pathways. The fasciculus gracilis carries sensory information from the lower limbs, while the fasciculus cuneatus carries sensory information from the upper limbs. These fasciculi terminate in specific nuclei in the medulla, where they synapse with the second neuron in their respective pathway. The axons then continue to ascend the brain stem as the medial lemniscus, terminating in the thalamus, where they synapse with the third neuron. The third neuron projects its axons to the postcentral gyrus of the cerebral cortex, where somatosensory stimuli are processed.