Commentary on the right hemisphere and a brain dichotomy

Abstract

More than a century ago, Paul Broca presented the case of a patient who had lost expressive language as a result of a left frontal lesion, thereby emphasizing the importance of the left hemisphere (LH) in verbal communication. This presentation began the period of localizationism in the history of neuropsychology, which reached its peak between 1920 and 1930, with the accumulation of anatomo-clinical observations and progress in the knowledge of the structure of the cerebral cortex. He also initiated the study of hemispheric dominance or specialization, which led to talk of a major or dominant hemisphere, the LH, and a minor, subordinate, minor hemisphere, the right hemisphere (RH). However, already at that time, a contemporary of Broca's, the English neurologist Hughlings Jackson, was able to suggest, based on his clinical experience, that RH also intervened in language, in its emotional or automatic aspects. In recent decades, extreme localizationism has been in retreat for two main reasons: first, it has been shown that in most higher brain functions (HBF), such as language, memory, attention, visual perception, etc., multiple areas of both hemispheres and also subcortical structures participate, forming a functional system.