Cognition

Abstract

An intelligent organism must recognize what and where the objects in its environment are; it should plan and execute action appropriate to the situation. A constantly updated record of experience must be kept, a record that, in humans, can be described with language. The first steps toward a neurobiology of cognition were taken in the late 19th century when it was discovered that many such higher mental functions could be selectively impaired by relatively focal brain lesions. Subsequent work has been devoted to obtaining a more detailed picture of possible behavioral fractionations and more precise anatomical clinical correlations as assessed either by histology at autopsy or by computerized axial tomography (CT) scans. Current studies have also emphasized the desirability of interpreting pathology within the framework of computationally explicit models of normal performance. The virtues of data that converge from different sources are obvious, although the possibility both of brain reorganization after pathology and of strategic adaptation to deficit cannot be discounted when drawing inferences about theories of normal cognition from lesion studies. Nonetheless, case studies of selective deficit following brain lesion have provided insight into the biological fractionation of mind.