ergic, serotonergic, and cholinergic components, with emphasis on the latter two as quantitatively and functionally the major players in control of the EEG and mental processes.
Several complications were alluded to that are not widely appreciated, for example, that the four systems are richly interconnected, that their effects are dependent on a remarkable diversity of postsynaptic receptors, that more than a single transmitter is likely to be released from a single presynaptic terminal in each of these systems, and that the effect achieved may be to switch the postsynaptic element from one functional state to another.
The unique bilaterality of the serotonergic system, its consistently dense innervation throughout the forebrain, and its vulnerability to viral and psychotogenic agents prompt the suggestion that its perturbation underlies the symptomatology of schizophrenia.
Several examples were offered in which activity in the primate visual system is dramatically altered by putative brainstem input. Finally, an experiment on split-brain macaques was summarized in which it can be seen that memories held by one hemisphere influence the accuracy, but not the latency, of responding by the other hemisphere, even though the memories per se of one hemisphere are unavailable to the other; this evidences a shared, and necessarily brainstem, mechanism in this form of mnemonic retention.
I am grateful to my colleagues, Roderick Davis, Barry Lee, Jeffrey Lewine, Jorge Pecci-Saavedra, Hisatoshi Sakakura, Paul Wilson, and the late John Bartlett, for a wealth of ideas and ardent dedication during the experiments briefly abstracted herein. Preparation of this manuscript was supported by a Javits Award, NS20052, from the National Institute of Neurological Disorders and Stroke.
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