Final answer:
The dorsal column system is the spinal tract responsible for light touch and proprioception, which crosses the midline in the medulla after ascending ipsilaterally in the spinal cord. The spinothalamic tract, in contrast, deals with pain and temperature sensations and crosses the midline at the level of entry in the spinal cord.
Step-by-step explanation:
The spinal tract that deals with light touch and proprioception is the dorsal column system. This tract originates from sensory neurons in the dorsal root ganglia. It carries information about touch and proprioception, and this information crosses the midline in the medulla. The dorsal columns ascend ipsilateral to the source of the stimulus and decussate in the brain stem. This system is critical for fine discrimination of touch and spatial orientation of body parts. In contrast, the spinothalamic tract is primarily responsible for pain and temperature sensations, and it decussates at the spinal level where it enters, ascending contralaterally.
To assess the function of these major ascending tracts, subtests are done using various sensory stimuli. Testing light touch helps to evaluate the dorsal column pathway, whereas testing for pain and temperature checks the integrity of the spinothalamic pathway. This segregation in sensory stimuli and their corresponding pathways allows clinicians to determine potential damages or disorders affecting these specific spinal tracts.