| Summary: | "When one attempts to formulate generalizations concerning neurophysiological discoveries, and to characterize their additions to the rich contributions of the Edwardian period, the introduction of a more operational point of view in both neuronal and brain functions seems to form a most obtrusive feature. Within the individual neuron, graded response mechanisms have been identified at either end of the classically conducting nerve fiber. These have greatly increased the scope of comprehension of neuronal function over that provided by the concept of all-or-none activity, now confined to the conducting portion of the axon. Within the brain, a central transactional core has been identified between the strictly sensory or motor systems of classical neurology. This central reticular mechanism has been found capable of grading the activity of most other parts of the brain. It does this as a reflexion of its own internal excitability, in turn a consequence of both afferent and corticifugal neural influences, as well as of the titer of circulating humors and hormones which affect and modify reticular activity. While the activities of this reticular system tend generally to be more widespread than those of the specific systems of the brain, it is proposed to be subdivided into a grosser and more tonically operating component in the lower brain stem, subserving global alterations in excitability, as distinguished from a more cephalic, thalamic component with greater capacities for fractionated, shifting influence upon focal regions of the brain. Influences of this reticular system which are directed spinalward modify central afferent transmission, as well as the activities of motor outflows from the cord, in particular those subserving posture. Reticular influences which are directed forward to the cephalic brain stem and rhinencephalon affect visceral and endocrine regulating systems and basal forebrain mechanisms for reward, punishment and emotion. Ascending reticular influences which are exerted upward upon the cerebral neocortex contribute to the initiation and maintenance of wakefulness and to the focus of attention. These manifold and varied capacities of the reticular system suggest that it serves importantly, and in the closest conjunction with the cortex, in the central integrative processes of the brain. In no area do the findings seem more intriguing than in the new developments exploring its involvement in conditioned learning."
"Individual chapters cover the following areas: Reticulospinal influences and postural regulation; Reticular influences upon central afferent transmission; Reticulo-hypothalamic influences and neuroendocrine regulation; Reticulo-diencephalic and rhinencephalic systems and emotion; Reticulo-cortical influences for wakefulness and attention; Non-specific brain mechanisms and neuropharmacology; and Reticular influences and cortical activity." (PsycINFO Database Record (c) 2006 APA, all rights reserved)
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