ASYMMETRY OF CHIMPANZEE PLANUM TEMPORALE - HUMAN-LIKE PATTERN OF WERNICKES BRAIN LANGUAGE AREA HOMOLOG

The anatomic pattern and left hemisphere size predominance of the plan um temporale, a language area of the human brain, are also present in chimpanzees (Pan troglodytes). The left planum temperate was significa ntly larger in 94 percent (17 of 18) of chimpanzee brains examined. It is widely accepted that the planum temporale is a key component of We rnicke's receptive language area, which is also implicated in human co mmunication-related disorders such as schizophrenia and in normal vari ations such as musical talent. However, anatomic hemispheric asymmetry of this cerebrocortical site is clearly not unique to humans, as is c urrently thought. The evolutionary origin of human language may have b een founded on this basal anatomic substrate, which was already latera lized to the left hemisphere in the common ancestor of chimpanzees and humans 8 million years ago.