The patient in the video had his corpus callosum removed in order to stop his seizures due to epilepsy. The procedure prevented the hemispheres from communicating with one another in any way and caused a sort of 'split consciousness'.
To reduce the severity of his seizures, Joe had the bridge between his left and right cerebral hemisphers (the corpus callosum) severed. As a result, his left and right brains no longer communicate through that pathway. Here's what happens as a result:
