Which syndrome results in loss of motor function on the same side as the lesion and sensory loss on the opposite side of the lesion?

Brown-Séquard syndrome is characterized by a hemisection of the spinal cord, leading to distinct neurological deficits. When a lesion occurs on one side of the spinal cord, the motor pathways that descend from the brain to control voluntary muscle movement are affected, resulting in loss of motor function on the same side as the lesion. Meanwhile, the sensory pathways that transmit pain and temperature sensations cross over to the opposite side of the spinal cord before reaching the brain. Consequently, this syndrome typically presents with loss of sensory perception, particularly pain and temperature, on the opposite side of the lesion.

This clinical presentation is critical in diagnosing Brown-Séquard syndrome as it helps distinguish it from other neurological conditions. For instance, Wallenberg syndrome primarily affects cranial nerves and results in different symptoms such as vertigo and balance issues. Guillain-Barré syndrome involves a more generalized peripheral neuropathy and does not conform to the specific hemisection symptoms described. Locked-in syndrome is characterized by preserved consciousness but loss of voluntary muscle control, and does not typically present with the specific sensory and motor dissociation found in Brown-Séquard syndrome.