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Biomedical subjects

M S Buchsbaum

Publications and source records attributed to M S Buchsbaum.

At least 217 records · Page 12Linked to original sources
PubMed1976

Evoked response and kinesthetic measures of augmenting/reducing in schizophrenics: replications and extensions.

This study represents an attempt to replicate the central results of earlier work on stimulus intensity control. It uses a diverse sample of 40 hospitalized schizophrenic subjects, both chronic and acute. Two measures of stimulus intensity control were used: the Petrie kinesthetic figural aftereffects procedure (KFA), and the EEG method of average evoked response (AER). Finding the earlier results generally applicable, it presents a model of the function of stimulus intensity control in schizophrenia, which suggests that acute schizophrenics are particularly vulnerable to being inundated by stimuli, and therefore, that in order to protect themselves, they tend to reduce the perceived intensity of stimuli. Chronic schizophreniics have higher AER amplitudes and reduce less than acutes, suggesting that among chronics, the reducing mechanism either never was present or failed, whereas paranoid schizophrenics tend to be augmenters--a response style consistent with vigilant scanning.

Acute Disease↗
PubMed1975

Schizophrenia and stimulus intensity control.

A group pf 19 acute, medication-free schizophrenic patients was studied, using average-evoked responses (AERs) to four intensities of light. Comparison with age- and sex-matched normal controls and patients with bipolar affective disorders showed that schizophrenics had smaller AER amplitudes and either no increase or an actual decrease in amplitude with increasing stimulus intensity. Normal subjects and schizophrenic patients were discriminated with 71% accuracy using AER variables; normals, patients with bipolar disorders, and schizophrenic patients with 64% accuracy. Patients who evidenced this AER "reducing" pattern to a noticeable extent early in hospitalization showed greater improvement and tended to have relatively good premorbid histories.

Acute Disease↗
PubMed1975

Effects of carbohydrate-active steroids and ACTH on visually-evoked responses in patients with adrenal cortical insufficiency.

Visual average evoked responses (AERs) to 4 intensities of light were studied in 5 patients with adrenal cortical insufficiency. Patients were tested off all medications, on ACTH while off all medications, and during replacement with carbohydrate-active steroids. Off treatment, when steroid levels were low, AERs were of small amplitude and short latency. Treatment with ACTH alone decreased the amplitude-intensity response, suggesting extra-adrenal effects. Both with amplitude and latency effects, stimulus intensity was an important parameter in determining steroid and ACTH effects.

Adolescent↗
PubMedDate not supplied

Abnormalities in hair trace elements as indicators of aberrant behavior.

There are long-standing viewpoints that impulsive and violent behavior may stem from brain dysfunction or damage secondary to head injury, disease, or toxic chemical substances. This research has aimed to examine the relationship between potentially toxic metals and aberrant behavior, especially violent activity, through the nonintrusive technique of hair analysis for trace elements. In an initial study, phase I, it was not possible to replicate findings of others who reported high levels of lead, cadmium, and copper in violent offenders. However, high levels of manganese were found in prison versus control groups. In phase II, the possibility of artifactual results arising from prison cooking utensils was controlled for by sampling early after incarceration. Phase III was included to substantiate the initial post hoc findings in an additional jail population. In both latter phases, significantly elevated manganese levels were found in the hair of violent versus nonviolent subjects (P less than .0001). A review of the effects of manganese at deficient and toxic levels does not provide a simple answer as to why manganese levels are elevated in the hair of individuals who have been incarcerated for violent behavior. Our study does not implicate the prison environment or soaps and shampoos used in California prisons. Other factors, such as alcohol, dietary, or psychosocial factors, might influence manganese levels in hair, or any of these factors might function in combination with mild manganese toxicity to contribute to aberrant behavior.

Adult↗
PubMedDate not supplied

The relationship between social alienation and disorganized thinking in normal subjects and localized cerebral glucose metabolic rates assessed by positron emission tomography.

This study investigated the relationships between the relatively mild manifestations in verbal behavior of social alienation and disorganized thinking in normal subjects and cerebral glucose metabolic rates measured by positron emission tomography (PET). Three groups of 10 young normal male subjects were injected with D-[18F]deoxyglucose (FDG) during either wakefulness, rapid eye movement (REM), or non-REM (NONREM) sleep, and 32 to 45 minutes later they were asked to report their thoughts, emotions, or dreams and free-associations to these mental events. Nonparametric correlations were obtained between measures of interpersonal social alienation, intrapsychic conflicts, and thought disorder derived from the typescripts of these reports by content analysis--using the Gottschalk-Gleser Social Alienation-Personal Disorganization Scale--and regional cerebral glucose metabolic rates obtained from PET scans. Total social alienation-personal disorganization scores obtained from the reports of wakeful, silent mentations showed significant positive correlations with glucose metabolic rates in the left temporal lobe. The patterns of significant correlations involving these verbal behavior measures derived from the content analysis of verbal reports of dreams or other mental events occurring during REM and non-REM sleep were in different cerebral locations from those found with these variables during silent, waking mentation. Previous observations suggesting that increased left temporal lobe glucose may typify chronic schizophrenia may instead be indicative of a wide range of thought disorder and/or social alienation manifestations occurring, at times transiently and minimally, in normal people.

Adult↗
PubMedDate not supplied

The effect of anxiety and hostility in silent mentation on localized cerebral glucose metabolism.

Ten normal, wakeful, young (average age, 25.3 +/- 6.6 years) male subjects received positron emission tomographic (PET) scans 45 to 120 minutes after an infusion of D-[18 F]deoxyglucose in order to assess localized cerebral glucose metabolic rates during silent visual and other sensory imagery and cognitive mentation. The typescripts of the verbal reports, limited to 5 minutes, of this type of mentation (including free-associations to all the silent mental events), were blindly content-analyzed to provide objective measures of various kinds of anxiety and hostility. Many significant positive and negative correlations were found in medial cortical, lateral cortical, and subcortical gray matter, and white matter areas between the magnitude of the anxiety and hostility aroused in the silent mental processes and localized cerebral glucose metabolic rates. Clearly, energy consumption in the brain, as judged from localized glucose metabolic rates, is highly influenced by the quality and quantity of emotionally tinged private reveries and mental events occurring spontaneously within human subjects. Brain areas involved with the processing of language, sensation, cognition, memory, and emotional reactions appear to be involved especially in these significant correlations. The implications of such findings in the neurosciences and behavioral sciences are discussed.

Adult↗
PubMedDate not supplied

Frontal cortex and basal ganglia metabolic rates assessed by positron emission tomography with [18F]2-deoxyglucose in affective illness.

Twenty affective disorder patients (16 bipolar and 4 unipolar) and 24 normal controls received scans with positron emission tomography (PET) using [18F]2-deoxyglucose (FDG) as a tracer. Subjects received a series of brief electrical stimuli to their right arms during FDG uptake. Patients with bipolar affective illness had significantly lower frontal to occipital glucose metabolic rate ratios (relative hypofrontality) and significantly lower metabolic rates in their basal ganglia in comparison to whole slice metabolism than normal controls. Patients with unipolar illness showed significantly higher frontal to occipital ratios, and also showed relatively decreased metabolism in the basal ganglia. All results in unipolar patients should be considered exploratory due to the small number of patients. Clinical depression ratings correlated negatively with whole slice metabolic rate.

Adult↗
PubMedDate not supplied

Effect of attention on frontal distribution of delta activity and cerebral metabolic rate in schizophrenia.

15 patients with schizophrenia and nine normal volunteers had 32 channel topographic EEG recorded for spectral analysis during the uptake of 18-F-deoxyglucose (FDG) for positron emission tomography (PET). Both patients and controls performed the Continuous Performance Test, a visual vigilance task, during FDG uptake. EEG was also obtained during an initial pre-FDG resting period. Each EEG epoch was individually inspected for eye movement artifacts. Analysis confirmed increased delta activity in the frontal region of patients with schizophrenia in comparison to normal controls, and a significant correlation between increased frontal delta and relative reduction in frontal lobe metabolism among patients with schizophrenia. This finding of increased delta is consistent with PET, blood flow and topographic EEG studies of schizophrenia, suggesting reduced frontal activity.

Adult↗
PubMedDate not supplied

Age-related shift in brain region activity during successful memory performance.

Coregistered positron emission tomography (PET)/magnetic resonance imaging (MRI) was used to characterize brain function in 70 volunteers, aged 20-87 years, during a verbal memory task. Frontal activity showed an age-related decline that remained significant after statistical control for sulcal atrophy. Analyses of young and old subgroups matched for memory scores revealed that young good performers activated frontal regions, whereas old good performers relied on occipital regions. Although activating different cortical regions, good performers of all ages used the same cognitive strategy semantic clustering. Age-related functional change may reflect dynamic re-allocation in a network of brain areas, not merely anatomically fixed neuronal loss or diminished capacity to perform.

Adult↗
PubMedDate not supplied

The cerebral neurobiology of anxiety, anxiety displacement, and anxiety denial.

BACKGROUND: Previous studies examining the relationship of anxiety scores, derived from the content analysis of speech of normal individuals, have revealed that the anxiety scores occurring in the dreams associated with rapid eye movement (REM) sleep are significantly correlated with localized cerebral glucose metabolic rates assessed by positron emission tomography (PET) scanning. These significant intercorrelations occur in different cerebral areas when the anxiety scores are obtained from mental experiences reported during non-REM sleep or during wakeful silent mentation. OBJECTIVE: The purpose of the present study was to examine the intercorrelations found between anxiety attributed to the self, anxiety-displacement, and anxiety denial measured from computerized content analysis of 5-min verbal reports of subjective thoughts and feelings obtained from wakeful normal subjects and localized cerebral glucose metabolic rates during PET scanning. METHODS: The subjects were 10 wakeful young males. Their anxiety scores were derived from computerized content analysis of 5-min reports they gave of their subjective thoughts, feelings and fantasies during a 30-min period following an intravenous injection of F D-deoxyglucose (FDG). The subjects were moved 32--45 min after this injection to obtain a PET scan, which records all of the localized cerebral glucose metabolic rates during the 30 min following the FDG injection. RESULTS: Significant intercorrelations of localized cerebral glucose metabolic rates with the scores of self-anxiety, anxiety displacement, and anxiety-denial were found in dissimilar cerebral locations depending on the type of anxiety involved. The significant correlations occurred in brain regions known to be associated with the functions of emotions, cognition, memory, and vision. CONCLUSIONS: Specific combinations of cerebral areas, based on glucose metabolic rates, appear to distinguish and be associated with different verbal expressions of anxiety. Replication of this preliminary research will be carried out.

Adult↗
PubMedDate not supplied

Explorations in the relationship of dream sleep to schizophrenia using positron emission tomography.

This study explored the relationship between rapid eye movement (REM) sleep and schizophrenia using positron emission tomography. Glucose use was compared between 49 schizophrenics, 30 awake controls and 12 controls in REM sleep. Assessment of the frequency and locations of brain areas showing significant differences suggested that REM did not resemble schizophrenia. Schizophrenics were between the higher awake controls and lower REM controls in corpus callosum glucose use. Hallucinating schizophrenics showed lower left caudate glucose use.

Adult↗