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

2008 ◽  
Vol 19 (4) ◽  
pp. 153-168
Author(s):  
Claude M. J. Braun ◽  
Anik Guimond
Keyword(s):  
Visual Imagery ◽  
Visual Hallucination ◽  
Right Hemisphere ◽  
Hemispheric Specialization ◽  
Unilateral Lesion ◽  
Temporal Lobes ◽  
Parietal Lobes ◽  
Multiple Case ◽  
The Right ◽  
Occipital Lobes

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.

scholarly journals Hypnotic visual hallucination induces greater lateralised brain activity than visual imagery

2021 ◽  
Author(s):  
Renzo C. Lanfranco ◽  
Álvaro Rivera-Rei ◽  
David Huepe ◽  
Agustín Ibáñez ◽  
Andrés Canales-Johnson
Keyword(s):  
Mental Imagery ◽  
Sensory Processing ◽  
Visual Imagery ◽  
Visual Hallucination ◽  
Right Hemisphere ◽  
Brain Activity ◽  
Top Down ◽  
Neural Processes ◽  
Sense Of Reality ◽  
The Right

AbstractHypnotic suggestions can produce a broad range of perceptual experiences, including hallucinations. Visual hypnotic hallucinations differ in many ways from regular mental images. For example, they are usually experienced as automatic, vivid, and real images, typically compromising the sense of reality. While both hypnotic hallucination and mental imagery are believed to mainly rely on the activation of the visual cortex via top-down mechanisms, it is unknown how they differ in the neural processes they engage. Here we used an adaptation paradigm to test and compare top-down processing between hypnotic hallucination, mental imagery, and visual perception in very highly hypnotisable individuals whose ability to hallucinate was assessed. By measuring the N170/VPP event-related complex and using multivariate decoding analysis, we found that hypnotic hallucination of faces involves greater top-down activation of sensory processing through lateralised mechanisms in the right hemisphere compared to mental imagery. Our findings suggest that the neural signatures that distinguish hypnotically hallucinated faces from imagined faces lie in the right brain hemisphere.

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

2007 ◽  
Vol 18 (2) ◽  
pp. 65-80 ◽  
Author(s):  
C. M. J. Braun ◽  
S. Desjardins ◽  
S. Gaudelet ◽  
A. Guimond
Keyword(s):  
Left Hemisphere ◽  
Right Hemisphere ◽  
Hemispheric Specialization ◽  
Body Schema ◽  
The Body ◽  
Parietal Lobes ◽  
Hemisphere Lesion ◽  
The Right ◽  
Internal Experience ◽  
And Behavior

The psychic tonus model (Braun and colleagues, 1999, 2002, 2003, 2006) states that the left hemisphere is a “booster” of internal experience and behavior in general, and that the right hemisphere is a “dampener”. Twenty-five patients with a “positive” extreme disturbance of body schema (somatoparaphrenia) and 37 patients with a “negative” disturbance of body schema (autotopagnosia or Gerstmann’s syndrome), all following a unilateral parietal lesion, were found in the literature and were analyzed to test predictions from Braun’s “psychic tonus” model. As expected, patients with a positive syndrome had a right hemisphere lesion significantly more frequently, and those with a negative syndrome had a left hemisphere lesion significantly more frequently. Thus the psychic tonus model of hemispheric specialization, previously supported with regard to psychomotor baseline, libido, talkativeness, memory, auditory and visual perceptual tonus, now incorporates the tonus of representation of the body (body schema) in the parietal lobes.

Neurospect Findings in Patients Exposed to Neurotoxic Chemicals

1994 ◽  
Vol 10 (4-5) ◽  
pp. 561-571
Author(s):  
Gunnar Heuser ◽  
Ismael Mena ◽  
Francisca Alamos
Keyword(s):  
Elderly Patients ◽  
Qualitative Analysis ◽  
Right Hemisphere ◽  
Young Patients ◽  
Chronic Fatigue ◽  
Psychiatric Symptomatology ◽  
Elderly Individuals ◽  
Parietal Lobes ◽  
The Right ◽  
The Brain

Exposures to neurotoxic chemicals such as pesticides, glues, solvents, etc. are known to induce neurologic and psychiatric symptomatology. We report on 41 patients 16 young patients (6 males, 10 females, age 34 8 yrs.) and 25 elderly patients (9 males, 16 females, age 55 7 yrs). Fifteen of them were exposed to pesticides, and 29 to solvents. They were studied with quantitative and qualitative analysis of regional cerebral bood flow (rCBF), performed with 30 mCi of Xe-133 by inhalation, followed by 30 mCi of Tc-HMPAO given intravenously. Imaging was performed with a brain dedicated system, distribution of rCBF was assessed with automatic ROI definition, and HMPAO was normalized to maximal pixel activity in the brain. Results of Xe rCBF are expressed as mean and S.D. in ml/min/100g, and HMPAO as mean and S.D. uptake per ROI, and compared with age-matched controls 10 young and 20 elderly individuals. Neurotoxics HMPAO Uptake Young Elderly R. Orbital frontal R. Dorsal frontal .70 .66 p < 0.05 R. Temporal .64 p < 0.001 R. Parietal .66 .66 We conclude that patients exposed to chemicals present with diminished CBF, worse in the right hemisphere, with random presentation of areas of hypoperfusion, more prevalent in the dorsal frontal and parietal lobes. These findings are significantly different from observations in patients with chronic fatigue and depression, suggesting primary cortical effect, possibly due to a vasculitis process.

DELUSIONAL MISIDENTIFICATION SYNDROME: DISSOCIATION BETWEEN RECOGNITION AND IDENTIFICATION PROCESSES

2019 ◽  
Vol 17 (4) ◽  
pp. 456-467
Author(s):  
Kamil Leis ◽  
Ewelina Mazur ◽  
Mariusz Racinowski ◽  
Tomasz Jamrożek ◽  
Jakub Gołębiewski ◽  
...  
Keyword(s):  
Right Hemisphere ◽  
Treatment Guidelines ◽  
Diagnostic Methods ◽  
Temporal Lobes ◽  
Neuronal Connections ◽  
Online Management ◽  
The Right ◽  
Misidentification Syndromes ◽  
Patient’S Will ◽  
Identification Processes

Delusional misidentification syndrome (DMS) is an umbrella term for syndromes of intermetamorphosis, Fregoli, and Capgras. DMS) is thought to be related to dissociation between recognition and identification processes. DMS was described for the first time in 1932 as a variant of the Capgras syndrome and is currently on the DSM-V list of diseases as an independent disease entity. Patients affected by DMS believed that people around them, most often family, have changed physically (appearance) and mentally (character). Other symptoms include confabulation, derealization or depersonalization. In patients, aggressive behavior is often observed, aimed at alleged doppelgangers resulting from the sense of being cheated and manipulated. With the intermetamorphosis syndrome, for example, schizophrenia, depression, bipolar disorder or other misidentification syndromes (Fregoli's, Capgras) may coexist. There is also a reverse intermetamorphosis, where the object of the changed appearance or character becomes the patient himself. One of its forms may be lycanthropy. The etiology of the intermetamorphosis has not been fully understood, one of the reasons may be brain damage and changes in the parietal and/or temporal lobes of the right hemisphere. It may then damage long neuronal connections to the frontal areas of the brain, disturbances of working memory (WM) accountable for the keep and online management of data, so that it is available for further processing, and the patient's will be uncritical. The basic method of diagnosis of this delusion is a medical interview with the patient. Other diagnostic methods include computed tomography, magnetic resonance imaging, EEG and ERPs. Experimental methods include searching for the neuromarker of DMS. Currently, there are no treatment guidelines of this delusional disorder, and pharmacotherapy experimental, but the drugs from the group of neuroleptics and lithium seem effective. Some hope for the treatment is created by neurotherapy, but it is also experimental.

Hemispheric Specialization and Cognitive Development: Implications for Mathematics Education

1978 ◽  
Vol 9 (1) ◽  
pp. 20-32
Author(s):  
Grayson H. Wheatley ◽  
Robert Mitchell ◽  
Robert L. Frankland ◽  
Rosemarie Kraft
Keyword(s):  
Left Hemisphere ◽  
Hemispheric Asymmetry ◽  
Right Hemisphere ◽  
Mathematics Curriculum ◽  
Hemispheric Specialization ◽  
Brain Hemispheres ◽  
Spatial Tasks ◽  
Concrete Operational ◽  
The Right ◽  
Hemisphere Specialization

Evidence is presented for hemisphere specialization of the two brain hemispheres: the left hemisphere specialized for logico-analytic tasks and the right hemisphere, visuo-spatial tasks. A hypothesis is put forth for the emergence of the specialization that suggests a shift from predominant right hemisphere processing in infancy to predominant left hemisphere processing in adulthood. Results of the studies reviewed suggest the emergence of concrete-operational thought as the left hemisphere becomes capable of processing logical tasks. Electroencephalography seems particularly useful in determining specialization and mapping changes in hemispheric asymmetry. Implications for school mathematics curriculum are presented.

Tactile Discrimination of Direction of Lines in Relation to Hemispheric Specialization

1982 ◽  
Vol 54 (2) ◽  
pp. 655-660 ◽  
Author(s):  
Daniela Brizzolara ◽  
Gianni L. De Nobili ◽  
Giovanni Ferretti
Keyword(s):  
Right Hemisphere ◽  
Hemispheric Specialization ◽  
Line Orientation ◽  
Contralateral Hemisphere ◽  
Tactile Discrimination ◽  
Experimental Procedure ◽  
Left Hand ◽  
The Right ◽  
Exploratory Movements

The role of the right hemisphere in a task of haptic discrimination of line orientation was studied in 16 children aged 7–6 and 16 adults aged 25 yr. The exploratory movements were limited to hand and wrist, since it has been shown that distal movements are mediated by the contralateral hemisphere. A comparison of the performance of the two hands shows a clear superiority of the left hand and inferred right hemisphere in both children and adults. An especial emphasis in the discussion is given to the role of the experimental procedure in enhancing the effect of the hemispheric functional asymmetries.

scholarly journals Hemispheric specialization for communicative processing: neuroimaging data on the role of the right hemisphere

2009 ◽  
Vol 2 (1) ◽  
Author(s):  
Rochele Paz Fonseca ◽  
Lilian Cristine Scherer ◽  
Camila Rosa de Oliveira ◽  
Maria Alice de Mattos Pimenta Parente
Keyword(s):  
Right Hemisphere ◽  
Hemispheric Specialization ◽  
Neuroimaging Data ◽  
The Right

scholarly journals Handedness Does Not Impact Inhibitory Control, but Movement Execution and Reactive Inhibition Are More under a Left-Hemisphere Control

Symmetry ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1602
Author(s):  
Christian Mancini ◽  
Giovanni Mirabella
Keyword(s):  
Left Hemisphere ◽  
Inhibitory Control ◽  
Right Hemisphere ◽  
Dominant Role ◽  
Hemispheric Specialization ◽  
Arm Movement ◽  
Proactive Inhibition ◽  
Stop Signal Task ◽  
The Right

The relationship between handedness, laterality, and inhibitory control is a valuable benchmark for testing the hypothesis of the right-hemispheric specialization of inhibition. According to this theory, and given that to stop a limb movement, it is sufficient to alter the activity of the contralateral hemisphere, then suppressing a left arm movement should be faster than suppressing a right-arm movement. This is because, in the latter case, inhibitory commands produced in the right hemisphere should be sent to the other hemisphere. Further, as lateralization of cognitive functions in left-handers is less pronounced than in right-handers, in the former, the inhibitory control should rely on both hemispheres. We tested these predictions on a medium-large sample of left- and right-handers (n = 52). Each participant completed two sessions of the reaching versions of the stop-signal task, one using the right arm and one using the left arm. We found that reactive and proactive inhibition do not differ according to handedness. However, we found a significant advantage of the right versus the left arm in canceling movements outright. By contrast, there were no differences in proactive inhibition. As we also found that participants performed movements faster with the right than with the left arm, we interpret our results in light of the dominant role of the left hemisphere in some aspects of motor control.

Lateralization of Language

2019 ◽  
pp. 876-906
Author(s):  
Lise Van der Haegen ◽  
Qing Cai
Keyword(s):  
Human Brain ◽  
Speech Processing ◽  
Right Hemisphere ◽  
Hemispheric Specialization ◽  
Unique Contribution ◽  
Language Impaired ◽  
Language Functions ◽  
Hemisphere Dominance ◽  
The Right

It is intriguing that the two brain halves of the human brain look so similar, but are in fact quite different at the anatomical level, and even more so at the functional level. In particular, the highly frequent co-occurrence of right-handedness and left hemisphere dominance of language has led to an abundance of laterality research. This chapter discusses the most important recent finding on laterality (i.e., left or right hemisphere) and degree of hemispheric specialization for speech production, auditory speech processing, and reading. Following a descriptive overview of these three core sub-processes of language, the chapter summarizes possible influences on the lateralization of each, including anatomical, evolutionary, genetic, developmental, and experiential factors, as well as handedness and impairment. It will become clear that language is a heterogeneous cognitive function driven by a variety of underpinning origins. Next, the often-underestimated role of the right hemisphere for language is discussed with respect to prosody and metaphor comprehension, as well as individual differences in the lateralization of healthy and language-impaired brains. Finally, recent insights into the relationship between lateralized language and non-language functions are discussed, highlighting the unique contribution of lateralization research to the growing knowledge of general human brain mechanisms.

scholarly journals Upright or inverted, entire or exploded: right-hemispheric superiority in face recognition withstands multiple spatial manipulations

PeerJ ◽  
2015 ◽  
Vol 3 ◽  
pp. e1456 ◽  
Author(s):  
Giulia Prete ◽  
Daniele Marzoli ◽  
Luca Tommasi
Keyword(s):  
Face Recognition ◽  
Social Interactions ◽  
Face Processing ◽  
Right Hemisphere ◽  
Hemispheric Specialization ◽  
Spatial Relations ◽  
Hemispheric Lateralization ◽  
Social Stimuli ◽  
Identity Recognition ◽  
The Right

Background.The ability to identify faces has been interpreted as a cerebral specialization based on the evolutionary importance of these social stimuli, and a number of studies have shown that this function is mainly lateralized in the right hemisphere. The aim of this study was to assess the right-hemispheric specialization in face recognition in unfamiliar circumstances.Methods.Using a divided visual field paradigm, we investigated hemispheric asymmetries in the matching of two subsequent faces, using two types of transformation hindering identity recognition, namely upside-down rotation and spatial “explosion” (female and male faces were fractured into parts so that their mutual spatial relations were left intact), as well as their combination.Results.We confirmed the right-hemispheric superiority in face processing. Moreover, we found a decrease of the identity recognition for more extreme “levels of explosion” and for faces presented upside-down (either as sample or target stimuli) than for faces presented upright, as well as an advantage in the matching of female compared to male faces.Discussion.We conclude that the right-hemispheric superiority for face processing is not an epiphenomenon of our expertise, because we are not often exposed to inverted and “exploded” faces, but rather a robust hemispheric lateralization. We speculate that these results could be attributable to the prevalence of right-handedness in humans and/or to early biases in social interactions.

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