Lesion in Wernicke's encephalopathy occurs in -
Mamillary body
Cerebellum
Motor cortex
Substantia nigra
In thiamine deficiency, hemorrhages into the mamillary bodies cause Wernicke-korsakof syndrome.
Other regions of CNS involved in thiamine deficiency are periventricular regions of the thalamus, the floor of the fourth ventricle and the anterior region of the cerebellum.