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Biomedical subjects

J E Bogen

Publications and source records attributed to J E Bogen.

At least 19 recordsLinked to original sources
PubMed1997

Does cognition in the disconnected right hemisphere require right hemisphere possession of language?

It has been asserted at times that the human right hemisphere is cognitively inferior to that of a chimpanzee or even a monkey. Related is the even stronger claim that human consciousness, as well as cognition, requires language. These claims are discussed, and counterexamples are presented from both split-brain subjects and patients hemispherectomized in adulthood after customary development as righthanders.

Brain↗
PubMed1995

On the neurophysiology of consciousness: I. An overview.

How certain neural mechanisms (Mc) momentarily endow with subjective awareness (C) percepts and affects represented elsewhere is more likely to be clarified when structures essential to Mc are identified. The loss of C with bilateral thalamic lesions involving the intralaminar nuclei (ILN) contrasts with retention of C after large cortical ablations depriving C of specific contents. A role of ILN in the perception of primitive (i.e., not cortically computed) sensations is suggested by their afference of directly ascending pathways. A role for ILN in awareness of cortical activity is suggested by their widespread afference from cortex, a property shared with striatum. A role for ILN in volition is suggested by their heavy projection to striatum. Unlike striatum, ILN also project widely to almost all neocortex, enabling an effect on ideation; this last property is in common with other structures (e.g., locus coeruleus) but none of them has the same direct cortical afference. And passage through the reticular nucleus (nRt) of ILN efferents to cortex could impact the attention-selective action of nRt. It is suggested that the quickest route to a better understanding of C involves more intensive study of ILN. No other structure seems, in the light of our current knowledge, a more likely site for Mc.

Awareness↗
PubMed1995

On the neurophysiology of consciousness: Part II. Constraining the semantic problem.

The main idea in this series of essays is that subjective awareness (more precisely, what I call C) depends upon the intralaminar nuclei of each thalamus (hereafter, ILN). This implies that the internal structure and external relations of ILN make subjective awareness possible. An array of material relevant to this proposal was briefly reviewed in Part I (Bogen, 1995). This Part II considers in more detail some semantic aspects and a bit of philosophic background as these pertain to propositions 0, 1, and 2 of Part I. Part II should be read in conjunction with Part I.

Animals↗
PubMed1988

Completeness of callosotomy shown by magnetic resonance imaging in the long term.

Six individuals who had complete cerebral commissurotomy for medically intractable epilepsy participated in a magnetic resonance imaging study 20 or more years postoperatively. In all cases the completeness of callosotomy was clearly demonstrable. The status of the anterior commissure, cut in all six, could not be confirmed with the same confidence.

Corpus Callosum↗
PubMed1988

Creativity and the corpus callosum.

A duality of mind is readily demonstrable in split-brain humans, and evidence is steadily accumulating that ongoing interhemispheric communication is incomplete in the intact brain. It is now certain that the corpus callosum can transfer high-level information from one hemisphere to another. When we take into account the well-established principle of hemispheric specialization, added to the impressive normality of split-brain humans in ordinary social situations, a physiologic explanation for at least some forms of creativity seems close at hand. What is required is a partial (and transiently reversible) hemispheric independence during which lateralized cognition can occur and is responsible for the dissociation of preparation from incubation. A momentary suspension of this partial independence could account for the illumination that precedes subsequent deliberate verification. From this point of view, we can understand better the opinion of Frederic Bremer, who wrote years ago that the corpus callosum subserves "the highest and most elaborate activities of the brain"--in a word, creativity.

Animals↗
PubMed1988

Alexithymia and the split brain: VI. Electroencephalographic correlates of alexithymia.

Electroencephalographic recordings of eight corpus callosotomy patients and eight precision-matched control subjects were obtained as subjects watched a film symbolically depicting death. A content-analytic measure of alexithymia was regressed on eight auto-spectral alpha-band intensity averages and on subsets of alpha-band coherence averages. Results were interpreted on the basis of three possible mechanisms of alexithymia: (1) Alexithymic subjects had more right-temporal alpha-band intensity, suggesting inadequate understanding of the film. (2) A possible lack of inner speech in alexithymics was suggested by their relative alpha abundance of the left frontal and left temporal channels but left parietal alpha desynchronization, and by their lower left frontotemporal but higher left parietofrontal and left parietotemporal coherences. (3) Alexithymic subjects had higher right frontal-left parietal and left frontal-left parietal coherences, suggesting possible interhemispheric inhibition of expression. Expressive subjects had higher right frontal-left temporal (and homologous interhemispheric frontal, parietal, and frontal) coherences, suggesting interhemispheric facilitation of verbal expression.

Adult↗
PubMed1987

Alexithymia and the split brain. V. EEG alpha-band interhemispheric coherence analysis.

Electroencephalographic (EEG) recordings were obtained while 6 completely commissurotomized patients, 2 partially commissurotomized patients, and 8 precision-matched normal control subjects watched 4 times a film symbolically depicting death. Our hypothesis was that alexithymia--a diminished capability to verbally express moods, symbols, and feelings--would be greater for patients because loss of cerebral commissures reduces interhemispheric communication, separating right-hemisphere-dependent affective understanding and left-hemisphere-dependent verbalization. Path and covariance structure analyses confirmed that callosotomy decreased alpha-band EEG coherences (after adjustment for mean intrahemispheric coherence) between pairs of scalp electrode channels placed homologously over frontal, parietal, and temporal lobes of the brain. This result occurred both for an index of interhemispheric coherence and for a latent variable indicated by the 3 adjusted coherences. Reduced levels of interhemispheric coherence in turn increased alexithymia, for an overall index and for a latent variable indicated by lexical-level content-analytic measures of verbal responses to the filmic stimulus.

Adult↗
PubMed1986

Are unilateral right posterior cerebral lesions sufficient to cause prosopagnosia? Clinical and radiological findings in six additional patients.

Controversy has arisen regarding the neuropathological basis of prosopagnosia. Some investigators suggest that bilateral lesions are needed to cause the deficit, whereas others felt that a unilateral right posterior lesion is sufficient. Six patients with prosopagnosia with clinical and radiological evidence of unilateral right posterior lesions are presented. Our observations together with evidence from similar cases described in the literature suggest that an appropriately placed right hemispheric lesion may be sufficient to produce prosopagnosia.

Agnosia↗
PubMed1986

Alexithymia: an experimental study of cerebral commissurotomy patients and normal control subjects.

This study assessed alexithymia in six patients with complete cerebral commissurotomy, two patients with partial commissurotomy, and eight matched control subjects. Comparisons were based on content-analytic measures of the subjects' spoken and written responses to a film that symbolically represented death and loss. The commissurotomized patients were more alexithymic on all four lexical-level variables, all six sentential-level variables, and all six global-level variables. Discriminant function analysis found a linear combination of four variables that effectively discriminated groups of fully commissurotomized, partially commissurotomized, and normal control subjects and correctly classified 15 of the 16 subjects.

Adult↗
PubMed1986

Mental duality in the intact brain.

It has been a signal honor to be president of the Los Angeles Society of Neurology and Psychiatry, which supported for 50 years a forum (the Bulletin of the Los Angeles Neurological Societies) for other than routine views, including those of its famous founders. One of these was Dr. J. M. Nielsen. I remember one of his brain cuttings relevant to this paper: After someone had read the history, he said, "Let's look at the anterior commissure." He held the brain with one hand and that big knife in the other (as you know, the anterior commissure is shaped like a handlebar mustache) and he made one curving sweep through the brain; then he lifted off the top half, and there was the full extent of the commissure. Another Founder, Dr. Cyril Courville taught me as a neurology resident for a year, followed by my time with Dr. Philip Vogel, whose skill and intestinal fortitude resurrected cerebral commissurotomy (1). Dr. Courville, as Editor of the Bulletin, was succeeded by Dr. Clarence Olsen who was succeeded in the Bulletin's 30th year by Dr. Richard Walter. This paper is an extension, to some extent, of my articles called The Other Side of the Brain which were published in the Bulletin in 1969 (2-4). Those articles presented ideas some of which may now seem fairly orthodox. But in those days they were not, and I think that Dr. Walter's publishing them was a tribute to his wry sense of humor, as well as his historical perspective.

Brain↗
PubMed1985

Alexithymia and the split brain. I. Lexical-level content analysis.

8 cerebral commissurotomy patients and 8 precision-matched normal control subjects were shown a 3-minute videotaped film symbolically depicting the deaths of a baby and of a boy. After each of 4 showings, all subjects were questioned about the symbolic and emotional contents of the film. Content analyses of the subjects' spoken and written responses were carried out on the lexical level. The commissurotomized patients, in comparison to their normal controls, used a lower percentage of affect-laden words, had a higher percentage of incomplete sentences, used a higher percentage of auxiliary verbs, and used a lower percentage of adjectives. Commissurotomy patients were significantly closer to the alexithymic pole of a factor derived from these 4 variables.

Adult↗
PubMed1985

Alexithymia and the split brain. II. Sentential-level content analysis.

The Hoppe-Bogen finding of alexithymia in 12 commissurotomy patients is examined, using 6 sentential-level items corresponding to 6 of the 8 key alexithymia items in the Beth Israel 'Psychosomatic Questionnaire'. 8 of the same commissurotomy patients and 8 precision-matched normal control subjects were shown a 3-min videotaped film about death. Content analyses of the subjects' spoken and written responses to this film were carried out, with directional support found for all items; however, only 2 of these differences in group means were statistically significant. The items were factor analyzed, and a 1-factor solution obtained. Factor score comparisons replicated the earlier study, as commissurotomy patients were found to be more alexithymic than normal controls.

Affective Symptoms↗
PubMed1985

Alexithymia and the split brain. III. Global-level content analysis of fantasy and symbolization.

8 commissurotomy patients and 8 precision-matched normal control subjects were shown a 3-min videotaped film about death. Content analysis of the subjects' spoken and written responses to this film was carried out on the global, interpretive level, for 2 fantasy and 4 symbolization variables. Commissurotomy patients were found to be significantly more alexithymic than normal controls for 3 of the symbolization variables, for factor-analytic measures of fantasy and symbolization, and for an over-all measure of alexithymia derived from these 2 factors and lexical-level and sentential-level measures of alexithymia.

Affective Symptoms↗
PubMed1985

Alexithymia and the split brain. IV. Gottschalk-Gleser content analysis, an overview.

A structural explanation of psychosomatic personality structure is proposed, that of a functional or physical deconnection of the two cerebral hemispheres. If the affective and symbolic energies of the right hemisphere cannot be externalized through verbal expressions of the left hemisphere (alexithymia), then they are apt to be directed inward, thereby contributing to psychosomatic personality structure. In an experiment, 8 cerebral commissurotomy patients and 8 precision-matched normal control subjects were shown a 3-minute videotaped film symbolically depicting the deaths of a baby and a boy. Gottschalk-Gleser content analysis of the subjects' verbal responses to the film was carried out for anxiety and hostility scales. A complex of shame and total anxiety in combination with hostility directed both inward and outward, was interpreted as an indicator of 'psychosomatic personality structure'. Cerebral commissurotomy patients showed a significantly higher level of psychosomatic personality structure than did normal controls.

Affective Symptoms↗
PubMed1983

A case report of pathological rule-governed syllable intrusion.

A detailed analysis of a unique speech disturbance, marked by the frequent appearance in the speech stream of a meaningless intrusive syllable, is presented. Following a lengthy thoracic surgery, an American English speaking patient began to speak with non-English prosodic patterns, which evolved to a conspicuous intrusion in his speech of the syllable /sis/. This syllable and its variants were attached to words in a manner which conformed to the regular phonological rules in English (for formation of plural, possessive, and third person singular morphemes). The distribution and frequency of the intrusive syllable are described, and possible explanations for the abnormal occurrence of this particular syllable are discussed.

Chondrosarcoma↗
PubMed1981

Disorganization and reorganization of cognitive and sensorimotor functions in cerebral commissurotomy. Compensatory roles of the forebrain commissures and cerebral hemispheres in man.

Neuropsychological studies of 10 patients with complete cerebral commissurotomy and 2 with frontal commissurotomy showed differences in the nature and severity of pre-operative, initial and long-term post-operative deficits in verbal and nonverbal cognitive, memory, and sensorimotor functions. Neurosurgical findings before and after operation recorded various types of extra-callosal brain damage in all 12 patients, including 4 with gross structural lesions in the right hemisphere before surgery. Our findings revealed that differences in the nature and severity of pre-operative and post-operative deficits varied according to the nature and laterality of associated extra-callosal damage before as well as after operation. Following complete commissurotomy, all 4 patients with pre-operative structural lesions of the right hemisphere revealed a unique pattern of marked, selective impairment of nonverbal cognitive functions strikingly similar to the effects of right hemispherectomy for tumour in adults. The remaining 8 patients showed systematic patterns of greater impairment in verbal and nonverbal cognitive and contralateral sensorimotor functions, depending on the laterality of extra-callosal damage. The significantly higher pre-operative Wechsler Performance IQs of the 4 patients with structural lesions of the right hemisphere suggest that following earlier damage to the right hemisphere, the forebrain commissures contribute to a reorganization of interhemispheric relations to permit restitution of the diminished nonverbal cognitive functions resulting from damage to the right hemisphere. Thus, in addition to other possible roles in integrating the functions of the two hemispheres in the normal brain, the forebrain commissures can also serve as 'standby' or 'reserve' structures for reorganization of compensatory interhemispheric mechanisms following lateralized brain insults. Since some patients showed later postoperative improvement, the extent of ultimate competence and the 'cognitive costs' of commissurotomy can only be defined by continuing follow-up studies. Apart from their practical clinical implications, such studies may also contribute to elucidation of the principles underlying the organization, disorganization and reorganization of human brain functions.

Adolescent↗