Final answer:
The Fasciculus cuneatus is the lateral division of the dorsal column system, carrying fibers from sensory neurons of the upper body. It synapses in the nucleus cuneatus in the medulla, with fibers crossing over and ascending to the thalamus and finally to the cerebral cortex for sensory perception.
Step-by-step explanation:
The ID structure of the Fasciculus cuneatus is part of the dorsal column system of the spinal cord and refers to the lateral division of this system. The fasciculus cuneatus is composed of fibers from sensory neurons in the upper body, including the arms. These axons ascend in the spinal cord and enter the brainstem to terminate in the nucleus cuneatus of the medulla, where they synapse with the second neuron. The second neuron projects and decussates in the medulla, ascending further as the medial lemniscus to reach the thalamus, synapsing there with the third neuron, which projects to the cerebral cortex.
The arrangement of the dorsal column system is such that it segregates signals originating in different parts of the body, with the more laterally positioned fasciculus cuneatus carrying sensations from the upper extremities. This system is crucial for precise touch and proprioceptive information transmission and is indicative of the complex connections within the subcortical structures, including the basal nuclei, as well as the organization of gray and white matter in the spinal cord.