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

This is Michael S. Gazzaniga writing again from the Center for Cognitive Neuroscience at Dartmouth, in the first person and in retrospect — the essay opens by recalling that "forty-five years ago, Roger Sperry, Joseph Bogen and I embarked" on the work. It is a stock-taking of the field he helped found, written for a broad neuroscience readership.

The piece ran in 2005 in Nature Reviews Neuroscience, a peer-reviewed review journal, as an Essay. Its purpose is to argue that the split-brain paradigm, far from being exhausted, still produces results — on the regional specificity of the callosum, on hemispheric specialisation, and on the integrative basis of the self — and to restate the interpreter as the mechanism that builds a unified narrative from a modular brain.

This sits as a secondary, retrospective review, lighter than the 2000 Brain synthesis and frankly partisan: it is a celebration of a paradigm by one of the three people who started it. As a survey it is reliable on what the field has established and openly invested in the interpreter framework it helped make canonical.

Gazzaniga's stake is reputational and proprietary. The essay is a victory lap for a research programme that is also his career, and it reaffirms the constructs — lateralisation, the interpreter — that he is identified with.