In a Brown-Sequard lesion, what type of sensory loss occurs on the same side as the injury?

In a Brown-Sequard lesion, which results from hemisection of the spinal cord, the type of sensory loss that occurs on the same side as the injury primarily involves touch and proprioception. This is due to the interruption of the dorsal columns, which carry these sensory modalities.

The dorsal columns ascend ipsilaterally (the same side as the injury) to the brain, so if there is damage to the spinal cord on one side, the ability to perceive fine touch, vibration, and proprioception on that same side is compromised.

In contrast, pain and temperature sensations are carried by the spinothalamic tract, which crosses over to the opposite side of the spinal cord shortly after entering. Therefore, in a Brown-Sequard lesion, these sensations are lost on the opposite side of the body from the injury.

Thus, the correct choice reflects the specific pathways affected by the lesion, focusing on the intact pathways for touch and proprioception on the same side as the injury.