- If the spinal cord is transected entirely, all sensations and motor functions distal to the segment of transection are blocked, but if the spinal cord is transected on only one side, the Brown-Sequard Syndrome occurs.  The effects of such transection can be predicted from knowledge of the cord fiber tracts.

-All motor functions are blocked on the side of the transection in all segments below the level of the transection.  Yet only some of the modalities of sensation are lost on the transected side, and others are lost on the opposite side.  The sensations of pain, heat, and cold - sensations served by the spinothalamic pathway

- are lost on the opposite side of the body in all dermatomes two to six segments below the level of the transection.  By contrast, the sensations that are transmitted only in the dorsal and dorsolateral columns - kinesthetic and position sensations, vibration sensation, discrete localization, and two-point discrimination - are lost on the side of the transection in all dermatomes below the level of the transection.  Discrete "light touch" is impaired on the side of the transection because of the principal pathway for the transmission of light touch, the dorsal column, is transected.  That is, the fibers in this column do not cross to the opposite side until they reach the medulla of the brain.  "Crude touch", which is poorly localized, still persists because of the partial transmission in the opposite spinothalamic tract.

- 4 classic findings of Brown-Sequard Syndrome is ipsilateral motor paralysis (spastic), ipsilateral loss of dorsal column, contra loss of spinothalamic, ipsilateral loss of all sensation at the level of the lesion.

- Brown-Sequard Syndrome is a lesion caused  by a hemisection of the spinal cord.

References:
1. Guyton, Arthur C., & Hall, John E. Textbook of Medical Physiology 11th Edition. 2006.