Split brain syndrome: One brain but two conscious minds?

• Published in: Journal of health research and reviews in developing countries Vol. 1; no. 2
• Main Authors: Agrawal, Divya, Mohanty, Biswa, Kumar, Sanjay, Chinara, Prafulla
• Format: Journal Article
• Language: English
• Published: Mumbai Medknow Publications & Media Pvt. Ltd 01.05.2014
• ISSN: 2394-2010; 2394-2029
• DOI: 10.4103/2394-2010.150793

The corpus callosum is the largest bundle of commissural fibers connecting the two cerebral hemispheres. The human brain actually functions as two individual brains capable of highly organized mental functions. The dominant hemisphere deals with speech, written language, mathematics, and grammar, whereas the non-dominant hemisphere deals with music, pictorial representation, spatial and temporal synthesis. When this connection is divided surgically, the patient shows what are known as disconnection syndromes which can be classified as acute and chronic. Based on the review of literature, we have tried to deal with the symptom complex of patients who have undergone commissurotomy as treatment for multifocal epilepsy. A selective literature search using the internet and e-library facilities was performed on the topic. The work of great neuropsychologists like Roger Sperry and M. S. Gazzaniga was studied and the differences in functions of the dominant and non-dominant hemispheres were compared. Based on this literature search, it was found that the corpus callosum helps in interhemispheric transfer of information and it is the co-ordination between the two hemispheres which allows us to perform activities smoothly and perfectly. If this connection is severed, actions performed by one hand cannot be understood by another. It was seen that speech, calculation, reasoning, personality, and intelligence are almost completely preserved after commissurotomy. However, cognitive impairment, abstract reasoning, short-term memory, and attention deficits have been reported. All the studies carried out in this field have suggested that the separation of the hemispheres creates two different spheres of consciousness within a single cranium. By using the split brain model, it can be concluded that a normal person's mind is the result of interaction between two separate states of consciousness.