Implications of Centrencephalic Theory
Traditionally, cognitive functions have been viewed as being processed almost exclusively by the cerebral cortex. In Pen-field’s view of brain function, however, the activities of certain brainstem formations (which we have termed the “centrencephalic core,” or CC) play a dominant role in the awareness of sensory experience, in the activation of stored information, in the orchestration of the various operations of the cerebral hemispheres, in the performance of problem-solving and other intellectual skills, and in the production of the stream of efferent impulses responsible for planned action. In earlier writings, Penfield (1952, 1954a,b, 1958) conjectured that the CC comprised certain nuclei within the diencephalon, midbrain, and pons. It was later intimated that the basal ganglia may also be included within the CC (Penfield, 1975a). (Although Penfield, 1975b, subsequently divided the CC into three functional parts—the “highest brain-mechanism,” the “automatic sensorimotor mechanism,” and the “record of experience,” we will only deal with the CC as a whole.) In order to add some degree of precision to this otherwise unstructured, but potentially testable theory, we have proposed that our lesion-identified nonspecific mechanism underlying problem-solving in the rat defines the composition of Penfield’s CC. In other words, the brainstem integrating area to which Penfield referred is estimated to consist of the dorsal caudatoputamen, globus pallidus, ventrolateral thalamus, substantia nigra, ventral tegmental area, superior colliculus, median raphe, and pontine reticular formation. It should be apparent, however, that the overall composition of this integrating ensemble (now termed the CCr) within the human (or infrahuman primate) brain may not be exactly the same as that within the rat brain. (As indicated later in this chapter, the prefrontal regions of the human brain may constitute a cortical extension of the CCr.)
KeywordsCerebral Cortex Basal Ganglion Mental Retardation Ventral Tegmental Area Memory Trace
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