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Forty-five years of split-brain research and still going strong


Forty-five years ago, Roger Sperry, Joseph Bogen and I embarked on what are now known as the modern split-brain studies. These experiments opened up new frontiers in brain research and gave rise to much of what we know about hemispheric specialization and integration. The latest developments in split-brain research build on the groundwork laid by those early studies. Split-brain methodology, on its own and in conjunction with neuroimaging, has yielded insights into the remarkable regional specificity of the corpus callosum as well as into the integrative role of the callosum in the perception of causality and in our perception of an integrated sense of self.

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Figure 1: Causal perception and causal inference in two split-brain patients.
Figure 2: Face recognition of self versus a familiar other in a split-brain patient.


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This research was supported by National Institutes of Health grants to the author. It was also supported by a graduate reseach fellowship from the National Science Foundation to M. Colvin. I would like to thank my collaborators, M. Colvin, M. Funnell, M. Roser and D. Turk, for their scientific input as well as their assistance in reviewing this paper. I would also like to thank R. Townsend for her editorial assistance.

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Gazzaniga, M. Forty-five years of split-brain research and still going strong. Nat Rev Neurosci 6, 653–659 (2005).

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