Visual Hypo and Hypergnosia as Exemplars of Poles of Psychic Tonus in the Occipital Lobes: Multiple Case Analyses

Abstract

The “psychic tonus” model or PTM [1] of hemispheric specialization states that the left hemisphere is a psychic and behavioral activator and that the right hemisphere is an inhibitor. The PTM predicts that the tonus of visual representation ought to manifest hemispheric specialization in the occipital lobes. Specifically PTM predicts that pathological positive visual tonus (visual hallucination) ought to be associated more frequently with right occipital lesions. PTM also predicts that pathological negative visual tonus (loss of visual imagery) ought to result more often from left occipital lesions. We reviewed 78 cases of post lesion hallucination and 12 cases of post lesion loss of evocation of images, all following a unilateral lesion. Analyses of these relevant previously published cases support the predictions. In accordance with previously published demonstrations of hemispheric specialization for auditory tonus in the temporal lobes and for somesthetic tonus in the parietal lobes, the present findings extend the psychic tonus model of hemispheric specialization to vision in the occipital lobes.

Evolution of hemispheric specialisation of antagonistic systems of management of the body's energy resources

“…Using the same selection criteria, Braun and Guimond (2007) reviewed published cases of visual hallucination due to a unilateral occipital lesion. They also reviewed previously published cases of loss visual imagination (without sensory loss, without loss of the capacity to copy a figure) due to a unilateral occipital lesion.…”

Psychic Tonus, Body Schema and the Parietal Lobes: A Multiple Lesion Case Analysis

“…It seems to be a fact that when parietal neocortex is damaged unilaterally, control circuits of psychic tonus can become skewed, and a corresponding disorder of body schema can ensue, positive or negative, as a function of which hemisphere is damaged. Similar phenomena are observed for the other lobes and their respective functions: visual for the occipital lobes [8], auditory, sexual and paralinguistic for the temporal lobes [4,5,7,9], psychomotor for the frontal lobes [3]. These phenomena form an ensemble, a behavioral, motivational and attitudinal system which boils down to a certain type of energy expenditure/economy or approach/avoidance dynamic.…”

“…Thus after a right hemisphere lesion, if a patient becomes manic, he/she (like any congenital manic) is also likely to be (but not necessarily) agitated, talkative, hypersexual, immunofacilitated, delusional and/or hallucinated. After a left hemisphere lesion, if a patient becomes depressed, he/she (like any congenital depressive) is likely to be (but not necessarily) lethargic, hypolalic, hyposexual, immunosuppressed and/or agnosic (see [1,[3][4][5][7][8][9][10] for reviews of the evidence).…”

“…The model draws equally from psychiatry as it does from neurology, as well as the biopsychology of normal and abnormal function in humans and animals. The model is based on demonstrations to the effect that mood [3], psychomotor baseline [3], libido [4], talkativeness [5], immune func-tion [6], memory [7], visual symptoms [8] and auditory symptoms [9] are all modulated in similar opposed ways by the two hemispheres, in right handers. The normal left hemisphere increases psychic tonus (infered from right hemisphere lesions), while the right decreases it (infered from left hemisphere lesions).…”