Exploring the Thalamus

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Summary: Your organ works thanks to the thalamic organist
Review: The human brain is dominated by the wrinkled sheet of gray matter called the neocortex. Almost all the information reaching this sheet arrives via an obscure but vital lump of 100 million nerve cells called the thalamus, the subject of Sherman and Guillery's exciting though forbidding book. The book is exciting because it breaks away from the sterile, narrow and hyperfactual approaches that have hitherto dominated this field. Even more exciting are the glimpsed possibilities it provides that if we could only understand the thalamus, we could perhaps also understand the neocortex, and hence, the human mind. The book is forbidding because the thalamus is complex, mysterious and seemingly useless - like the hieroglyphics carved on an old pointed rock sold in a bazaar as a hatrack. Other far more expensive tomes on the thalamus insist that it is merely a hatrack, but Sherman and Guillery rightly concentrate on the hieroglyphics, though they ultimately admit themselves stumped. We still do not know what the thalamus does, but the authors bring a number of new issues to center stage that will surely be part of the solution. First, the main cells of the thalamus can send two quite different sorts of electrical message to the cortex. Second, the message selection hinges on "modulatory" influences arriving from the cortex itself as well as deep brain regions that control sleep, dreams and attention. Third, when one part of the neocortex communicates with another, it often does so via the thalamus, as though it cannot understand messages unless they are thalamically interpreted. If you want to reach the basecamp that leads to the unconquered Everest of science, the human brain, struggle through this book.