Psychic tonus, body schema and the parietal lobes: a multiple lesion case analysis.

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.

Ventral frontal deficits in psychopathy: neuropsychological test findings.

The hypothesis of prefrontal dysfunction in psychopathy has been pursued for many years, without convincing results. It is proposed here that this approach in previous studies was far too global. The present investigation was carried out in order to test a more specific hypothesis of orbitofrontal and/or frontal ventromedial deficits in psychopathy. Psychopathic criminals were compared to non-psychopathic criminals with measures related to orbitofrontal or frontal ventromedial functioning, as well as with control measures more associated with frontodorsolateral and posterorolandic functions. All subjects provided urine samples for drug assay. It was found that, while the two groups performed similarly on all the control measures, including the drug tests, the psychopaths were significantly impaired on all the orbitofrontal-ventromedial tasks. The psychopaths were significantly impulsive on several tests as well as significantly dysosmic [corrected]. The latter finding is particularly important in the sense that it cannot readily be explained socioculturally, thus presenting a new and convincing argument for brain-based etiology of this disorder. The results are discussed in relation to other psychiatric disorders characterized by impulse dyscontrol as well as in relation to other putative neurobiological etiological factors in psychopathy.

Intermanual transfer of somaesthetic information: a two-point discrimination experiment.

Twenty-four men and 24 women, all university students, judged whether two-point aesthesiometric applications, either both to the same palm (intramanual condition) or one to each palm (intermanual condition) were of the "same" or "different" spans. The main question was to determine the extent to which there is a loss of accuracy during intermanual comparisons, and by inference, interhemispheric relay. A second question, the extent to which this loss is a function of the difficulty of the task, was to be answered by the inclusion of span-differences above, at, and below threshold. Difficult trials were associated with a highly significant intramanual advantage of 4.74%, and easy trials with a non-significant intramanual advantage of 1.16%. For both intra- and intermanual conditions, subjects made more errors as a function of decreasing "span-difference". The two hands performed equally well, and the order of stimulation between the two hands made no difference in the results. The intramanual advantage could not be construed as an effect of response set (i.e., an artefact of subject's inherent bias for "same" or "different" judgements), nor as a scaling effect (e.g., of span scales relating to receptive field properties, relating in turn to interhemispheric relay). There was no evidence of a sex difference in basic ability, nor in the cost of hemispheric relay. It was concluded that there is a loss of precision in interhemispheric relay of somaesthetic discrimination, but this can only be detected close to threshold.

Co-regulation of antigen-specific T lymphocyte responses by type I and type II cyclic AMP-dependent protein kinases (cAK).

While a differential sensitivity to cyclic AMP (cAMP)-mediated signaling between Th1 and Th2 cells has been hypothesized, differential activity of downstream signaling through cAMP-dependent protein kinase (cAK) isoforms remains unexplored. We herein report the effects of type 1- and type 2-specific cAK agonists and antagonists on proliferative responses and cytokine generation from ragweed-driven peripheral blood mononuclear cells (PBMCs) and Amb a 1-specific Th1 and Th2 clones. Rp-8-Cl- and Rp-8-CPT-cAMP were utilized as single agent antagonists of cAKI and cAKII, respectively; 8-AHA-cAMP, with and without 8-PIP-cAMP, and 8-CPT-cAMP, with and without 6-Bnz-cAMP, were used as synergistic agonist pairs specific for the cAKI and cAKII, respectively. Activation of either cAKI or cAKII individually was ineffective in down-regulating proliferative responses of PBMCs or T cell clones; concentration-response curves for the Th1 and Th2 clones were identical. Moreover, inhibition of either cAKI or cAKII individually was ineffective in overcoming the down-regulatory effects of phosphodiesterase inhibition. Activation of either cAKI or cAKII individually was ineffective in down-regulating proinflammatory cytokine generation from T cell clones (interleukin-4 from Th2; interferon-gamma from Th1). However, concurrent activation of both cAKI and cAKII produced down-regulatory effects equivalent to those of the phosphodiesterase inhibitor on both proliferation and cytokine generation. These data suggest a critical role for concurrent activation of cAKI and cAKII in the functional efficacy of antigen-driven downstream signaling due to elevations of intracellular cAMP and argue against differential regulation of Th1 and Th2 responses by cAK subtypes.

Effects of locus coeruleus lesions upon sleeping and waking in the rabbit.

The effects of radiofrequency lesions in the region of the locus coeruleus (LC) upon sleep--waking states and behaviors were investigated in chronically implanted New Zealand White rabbits. Polygraphic recordings were taken prior to and at 5- and 14-day intervals following lesioning. In animals exhibiting absence of paradoxical sleep and the presence of bizarre motor behavior, additional recordings were taken 30 days postlesion. Prelesion sleep-wakefulness pattern data were comparable to those previously observed in intact rabbits, including the recently reported absence of sustained PS-related nuchal muscle atonia. Lesions histologically localized to the area of the locus coeruleus were of two types, i.e., those effecting bilateral destruction of greater than or equal to 80% (n = 11) or 30-50% (n = 11) of the LC. A transient period of inactivity was present immediately following lesioning, but by two weeks postlesion animals had generally regained normal waking behavioral and physiological functioning, e.g., eating, drinking and grooming behaviors had returned and respiration, micturition and general urological functioning were normal. The more extensive LC lesions were followed by increases in the proportion of total recording time spent in wakefulness, but primarily in quiet rather than active wakefulness. Sleep was fragmented by phasic muscular activation in proportion to the amount of LC destroyed. In animals with the most extensive lesions, slow wave sleep was interrupted by brief, abrupt episodes of twitching, and episodes of marked phasic muscular activation, often violent in nature, occurred following periods of slow wave sleep. The postlesion occurrence of PS was inversely related to the degree of LC destruction and, accordingly, to the presence of episodes of phasic motor activation. These results did not confirm earlier reports in other species implicating the LC in urogenital functioning and respiration, but do corroborate previous findings indicating that neural elements in the LC regions are essential to the integrity of sleep and are especially important to the control of motor mechanisms during sleep.

Neuropsychological correlates of violence in schizophrenia.

Thirty-one outpatient men with schizophrenia were assessed with various measures of lifelong history of physical violence as well as psychopathology, neuropsychological performance, and neurological intactness. Most of the results consisted of nonsignificant positive relationships between physical aggression and neuropsychological performance in these schizophrenia subjects. Some neuropsychological test performances did show significant positive correlations with levels of aggressivity. In contrast with previous studies that have established a relation between neuropsychological impairment (as opposed to performance) and violence in schizophrenia, subjects of the present study were high-functioning outpatients who may not have attained a level of neurological impairment inducing constant uncontrollable outbursts of irritative aggression in their daily living. The importance of defining in detail the clinical characteristics of the subjects studied and the type of violence assessed is discussed, and an ecological interpretation of these counterintuitive results is provided.

Effects of brainstem lesions on tonic immobility in the rabbit (Oryctolagus cuniculus).

Lesions were placed in discrete brainstem areas implicated in the generation of both tonic immobility (T1) and paradoxical sleep (PS) to examine postulated state and event correspondences between these states in the rabbit. Lesions were concentrated in the region of the nucleus locus coeruleus (LC)-an area implicated in the mediation of muscular atonia during PS-but also included other reticular (pontine gigantocellular tegmental field: FTG), and nonreticular (vestibular, cerebellar, central grey, collicular) areas. Polygraphic recordings of EEG, EMG and EOG activities were taken during sleep-waking states and measures of the TI response were obtained before (1 day prior) and after (5 and 14 days) lesions were made. None of the lesions was followed by a sustained, significant variation in either frequency of induction or duration of TI. Following LC lesions, and to a lesser extent after FTG lesions, sleep patterns were fragmented, with a reduction or absence of PS and the occurrence of phasic motor activation at times when PS periods might be expected to occur. The absence of PS and persistence of TI following specific brainstem lesions indicate a fundamental difference in mechanisms underlying these states. It is suggested that a major determinant of these results is the activation of phasic activity during PS but not TI, and that the possibility remains that both states may share a common mechanism of tonic motor control.

Emotional facial expressive and discriminative performance and lateralization in normal young adults.

Studies of cerebral dominance for posed emotional facial expression using free-viewing of hemicomposites have produced inconclusive findings, and the concordance of facial emotion identification (discrimination) and the expression of the same facial emotion remains unknown. Expressive and discriminative (14 men, 14 women) facial emotion performances of undergraduates and the lateralization of full-face and lower-face hemicomposite photographic montages of the expressions of six transcultural emotions (joy, sadness, fear, surprise, disgust, anger) as ascertained by 15 male and 15 female undergraduate judges were analyzed. All groups were matched for age and education. The lower face was non-significantly left-face dominant, sadness was strongly significantly right-face dominant and fear was non-significantly left face dominant. Both sexes were equally lateralized overall and demonstrated the same pattern as described above, though slight (apparently trivial) differences appeared in multivariate analysis, and in univariate interactions. Results were interpreted as non-supportive of a simple right hemisphere dominance model of facial affect, nor of a left-hemisphere-negative/right-hemisphere-positive model. It was concluded that facial affect dominance results are coherent only within, and not between, methods such as free viewing hemicomposite and tachistoscopic methods, and tasks, such as expressive and discriminative tasks.

Topography of averaged electrical brain activity relating to interhemispheric dynamics in normal humans: where does the critical relay take place?

Interhemispheric relay time (IHRT) was investigated using a 16-electrode montage in 10 normal subjects during a simple visual reaction time task (Poffenberger paradigm). The P1 latency was the dependent measure. Response-locked components were separated from the stimulus-locked components based on the reaction times using a Woldorff-like filter. The issues of theoretical interest were the following: (1) does the responding hand modulate IHRT estimates as a function of electrode site, or stimulated field?; (2) what are the respective advantages of various pairs of symmetrical across-midline electrode sites for tracking IHRT?; and (3) what are the respective advantages of symmetrical vs. asymmetrical across-midline electrode site-pair configurations for tracking IHRT? There were significant lags attributable to IHRT in both evoked potential P1 latencies and in reaction times--but these were uncorrelated. The responding hand was not found to significantly modulate IHRT estimates derived from the P1 peak latency of response-corrected ERPs. Anterior sites yielded more precocious components and briefer estimates of IHRT which were closer to those observed in reaction time estimates. However, posterior leads yielded more reliable estimates. Various analyses suggested that IHRT can be tracked, very vaguely, with asymmetric configurations as well as symmetric ones, each for different reasons.

Color discrimination testing reveals early printshop solvent neurotoxicity better than a neuropsychological test battery.

Twenty standardized neuropsychological tests were compared to the Lanthony D-15 desaturated panel test of chromotopsia to determine which measures would most effectively discriminate solvent-exposed print workers from controls. All the workers of the printing services of Université du Québec a Montréal (N = 29) were assessed excepted one who refused to participate. Twenty-nine workers (employed on a full time basis) matched for occupation, age, sex, education, vocabulary, and written arithmetic (p >.13) with the print workers served as controls. Air samples revealed exposure to ethanol, perchloroethylene, methyl chloride, xylene, toluene, and stoddard solvent in the print shop. None of the 20 neuropsychological measures yielded a statistically significant decrement in the print workers. On the other hand, the Lanthony D-15 test revealed a significant group difference (p <.01) and a highly significant interaction between job category within the print shop and dyschromatopsia (p <.001) - the graphists, photocopiers, and printers/binders manifesting increasing severity of impairment as a function of increasing magnitude, and/or type, of dose. The results were interpreted to mean that in a cohort of printers with low seniority (10.42 years) such as this one, neuro-opthalmotoxic effects can be observed earlier than putative neuropsychotoxic effects with the tools at hand.

Neurological soft signs in schizophrenia: are they related to negative or positive symptoms, neuropsychological performance, and violence?

This investigation was carried out on 31 unemployed schizophrenic outpatient men. The general purpose was to explore new aspects of neurological soft signs in schizophrenia. A 108-item version of the Nathan Kline Institute scale of soft signs, the Schedule for Affective Disorders and Schizophrenia psychiatric interview, the negative and positive symptom scale (PANSS), a comprehensive scale of life-time history of violence, and a large set of neuropsychological tests were administered. It was found that "motor" soft signs were significantly more prevalent than "sensory-perceptual" signs, but that each body side manifested equal numbers of neurological signs. Before and after statistical correction for age, education, alcoholism, drug abuse disorder, and daily and cumulative neuroleptic dosage, orbitofrontal-type neuropsychological tasks measuring "impulsivity" related very robustly to the soft signs. Furthermore, before and after the same statistical corrections, right body-side signs correlated significantly with the same neuropsychological tests, whereas left body-side signs did not. The PANSS scores and levels of lifetime violence generally did not correlate significantly with neurological soft signs. The latter negative findings, we think relate to the fact that these were relatively high-functioning (i.e., outpatient) schizophrenics. Overall, the results support notions of frontal lobe and left hemisphere involvement in schizophrenia, these two dysfunctional systems being apparently linked at the level of the orbitofrontal area of the brain.

Effects of right and left hemisphere cerebrovascular lesions on discrimination of prosodic and semantic aspects of affect in sentences.

Ten nonaphasic left cerebrovascular accident (CVA) patients, 12 right CVA patients, and 16 normals were matched for age, education, lesion sizes, and postonset intervals; all were right handed. One task consisted of 36 sentences connoting one of six primary emotions (joy, sadness, fear, surprise, disgust, anger) presented binaurally with a neutral emotional tone. Subjects were required to point to the appropriate emotion name on a vertically arranged list. A second task consisted of the same 36 sentences voiced emotionally by humming with a closed mouth, presented binaurally, and requiring the same response as for the preceding task. A third task consisted of 18 of the sentences spoken with concordant emotional tone and the remaining 18 sentences spoken with discordant emotional tone, presented binaurally and requiring pointing to the word "SAME" or "DIFFERENT" arrayed vertically. The right hemisphere (RH) patients were significantly impaired, relative to the left hemisphere (LH) patients and normals, on the pure prosody task (2) and on the emotional concordance task (3), the latter effect being significant only for mismatch categorization. The LH patients performed (nonsignificantly) less well than the RH patients and normals on the verbal contextual task (1). Performances on the three tasks were not significantly correlated in the patient groups. It was concluded that the RH probably dominates for phonetic discrimination of vowel trains (fundamental frequency and/or single vowel or multivowel contour) and that the RH probably dominates for certain forms of selective attention in the verbal domain perhaps involving simultaneous mismatch treatment of ongoing sentence-level, distracting, complementary, verbal processes. Comparison of similar right and left, cortical (frontoparietal), and subcortical (capsule and basal ganglia) lesions suggested, but did not prove, that the RH pure prosody impairment is cortical whereas the RH tonal-semantic mismatch categorization impairment involves subcortical as well as cortical contributions.

A comparison of functional indexes, derived from screening tests, of chronic alcoholic neurotoxicity in the cerebral cortex, retina and peripheral nervous system.

Thirty abstinent alcoholics and 30 age-, education- and occupation-matched normal control subjects were tested with the Category test, the Lanthony-15 test of color discrimination and the Biothesiometer test of vibration detection threshold. Multivariate analysis of covariance revealed significant impairment of the alcoholics on these tasks (p < .007), but univariate analysis revealed that only the Category test yielded a significant difference (p < .001). Canonical correlation analysis, with age and education partialed out, was calculated on the alcoholics' data to determine whether duration, mean and maximum alcohol consumption, age of onset of alcoholism and duration of abstinence predicted performance on the tasks. The prediction was significant (p < .001). Multiple regression analysis revealed that vibration threshold, color preception and Category test performance were decreasingly predicted by the alcohol-related variables (p < .001, .006, .051, respectively). There was no higher incidence of hereditary dyschromatopsia in the alcoholic group than the control group. It was therefore concluded that all three functions (Category test performance, color discrimination, vibrotactile sensitivity) were impaired as a result of alcohol consumption.

The Geschwind-Behan-Galaburda model (GBGM) of cerebral lateralization: a critique and prospective.

In the wake of, and as a complement to, a recently published major meta-analytic review of empirical support of the Geschwind-Behan-Galaburda model (GBGM) of cerebral lateralization (CL) the present brief essay attempts to present a critical assessment of the theoretical approach underlying the GBGM. The GBGM is criticized for having been misguided in its representation of the cerebral basis of handedness, and of the links between testosterone and immune function. Some guidelines are presented for the development of a general theory of CL, emphasizing animal research, greater interdisciplinary communication, a hierarchical model-building approach, and the relevance of neuropharmacology and psychiatry.

Interhemispheric transfer in Down's syndrome.

Callosal agenesics and callosotomized epileptics manifest markedly increasing simple visual reaction time (SVRT) from conditions of ipsilateral to contralateral stimulus-response relation (SRR). In the contralateral SRR, a response is presumed possible because of presence of other commissures (anterior, intercollicular). The SRR effect is prolonged presumably because the remaining commissures are less efficient than the corpus callosum in relaying necessary visual or motor information. Consequently, the SRR effect is believed to correspond to callosal relay time (CRT) in the normal subject. However, both callosal agenesics and callosotomy patients manifest general slowing of SVRT in addition to a prolonged SRR effect. These patients have massive extra-callosal damage which could plausibly cause both the SVRT and the CUD prolongation. If such were the case, the CRT inference would be in jeopardy. A test of the CRT inference is therefore required where patients with massive diffuse extra-callosal brain damage and normal callosi would show marked general SVRT prolongation and a normal SRR effect. Four trisomy-21 (T21) males were compared to age and sex-matched normal controls. General SVRT was highly significantly prolonged in T21, but the CUD was nearly identical in both groups.

A 54-point verbal-performance IQ discrepancy on the WISC-R: cognitive functioning of a child from an alternative school.

Marked WISC-R verbal-performance discrepancy commonly leads to the assumption that such children have brain pathology or cognitive disorders. Children without brain dysfunction may also exhibit wide discrepancy, but a discrepancy score of 30 is assumed to occur in only 2% of the population. The actual investigation presents an 11-year-old child showing a 54-point discrepancy between the two scales of the WISC-R. Results of wide ranging testing and other considerations strongly suggested that this child didn't manifest any kind of brain dysfunction. It was concluded that the particular academic environment of the child, an alternative school, exerted a very strong influence on her results on the WISC-R. This conclusion is furthermore supported by the results of a follow-up evaluation, done 1 year after the child has been transferred to a traditional school, which revealed a WISC-R verbal-performance discrepancy of only 12 points.

Prevalence, and intellectual outcome of unilateral focal cortical brain damage as a function of age, sex and aetiology.

Neurologists and neuropsychologists are aware that aging men are more at risk than women for brain damage, principally because of the well known male-predominant risk for cardiovascular disease and related cerebrovascular accidents. However, a disproportion in prevalence of brain damage between the sexes in childhood may be less suspected. Furthermore, sex-specific risk for other aetiologies of brain damage may be little known, whether in the pediatric or adult populations. Proposals of a sex difference in cognitive recovery from brain damage have also been controversial. Six hundred and thirty five "consecutive" cases with cortical focal lesions including cases of all ages and both sexes were reviewed. Aetiology of the lesion was determined for each case as was postlesion IQ. Risk was highly male prevalent in all age groups, with a predominance of cardiovascular aetiology explaining much of the adult male prevalence. However, several other aetiological categories were significantly male prevalent in juveniles (mitotic, traumatic, dysplasic) and adults (mitotic, traumatic). There was no sex difference in outcome (i.e., postlesion IQ) of these cortical brain lesions for the cohort as a whole, after statistical removal of the influence of lesion extent, aetiology and presence of epilepsy. Mechanisms potentially responsible for sex differences in prevalence, aetiology of brain damage, and recovery, are reviewed and discussed.

Cancer care in Nepal: variables that affect diagnosis, treatment, and prognosis: a case study.

This manuscript presents a case study of a Nepalese woman experiencing breast cancer. Six themes were identified to have an impact on the diagnosis, treatment, and prognosis. They include: cultural impact on women's roles, socioeconomic status and education, surgical oncologist-patient relationship, surgical oncologist-nurse relationship, nurses' lack of oncology knowledge, and lack of a cancer screening and prevention program in Nepal. Cancer care is on the rise in Nepal. However, many of the variables identified above are not considered in the cancer care provided. Nepal has just opened its first national cancer center with the intent to improve cancer care throughout the country.

Effects of memory load on interhemispheric relay.

Experimentation with unilateral and bilateral tachistoscopic stimulation (the Dimond paradigm) increasingly suggests that interhemispheric cooperation (bilateral advantage) occurs or increases as a function of task complexity in general and memory load in particular. However, tachistoscopic experimentation with ipsilateral and contralateral field/hand relation conditions (the Poffenberger paradigm) has failed to provide any conclusive supporting evidence. The present investigation comprised a Sternberg "high speed memory scanning" task, modified as a go/no-go task, and formatted into the Poffenberger paradigm. Sets of items to be scanned (memory load) varied in size from one to four. A highly significant effect of load and a significant field/hand interaction were found, but the field/hand/load interaction did not reach significance. We concluded that the interhemispheric transfer time (ITT) metric drawn from this paradigm is not reliably sensitive to increasing memory load. However, our finding of significantly longer ITT in women than in men suggests that commissural anatomy and physiology may be sexually dimorphic.

Dissociation of hemispheric exploitation of rods and cones for simple detection.

Sergent (1982a, 1982b, 1982c) proposed that stimuli carrying high luminous energy will be better detected in the right field (left hemisphere) and stimuli carrying low energy in the left visual field (right hemisphere). A photoreceptor-based model could explain the same effects as well as several others (eccentricity effects, retinal adaptation effects). Braun, Mailloux, and Dufresne (1995) suggested that cones might favor right field stimuli and rods might favor left field stimuli. We implemented a series of near-threshold simple detection experiments comprising stimuli varying along four dimensions (color, eccentricity, duration, and size) in dark-adapted subjects. Consistent and significant right field advantages accrued for near-meridianal foveal red stimuli, but there were no field effects for eccentric blue stimuli. An alternative to Sergent's stimulus energy model and the photoreceptor-based model, namely a parvocellular-magnocellular model, is proposed.