Biomedical subjects

M S Buchsbaum

Publications and source records attributed to M S Buchsbaum.

At least 109 records · Page 6Linked to original sources

PubMed1990

The frontal lobes, basal ganglia, and temporal lobes as sites for schizophrenia.

Positron emission tomography studies with fluorodeoxyglucose in patients with schizophrenia are reviewed and findings in the frontal lobes, basal ganglia, and temporal lobes summarized from more than 20 published studies. Despite methodological and clinical population differences between studies, most reports indicate that patients with schizophrenia are more likely to be low in these areas than in the occipital lobe, cerebellum, or in white matter. This is consistent with blood flow and some neuroanatomical findings. Cluster analysis on our own sample suggests that patients may be low in all three areas rather than a pattern of three distinct clusters. Further study of individual symptom differences, medication effects, and of psychophysical tasks salient for these brain areas is indicated.

Basal Ganglia↗

PubMed1990

Greater left cerebral hemispheric metabolism in bulimia assessed by positron emission tomography.

Eight women with bulimia and eight age- and sex-matched normal control subjects were studied with positron emission tomography using [18F]-fluorodeoxyglucose (FDG) as a tracer of brain metabolic rate. Subjects performed a visual vigilance task during FDG uptake. In control subjects, the metabolic rate was higher in the right hemisphere than in the left, but patients with bulimia did not have this normal asymmetry. Lower metabolic rates in the basal ganglia, found in studies of depressed subjects, and higher rates in the basal ganglia, reported in a study of anorexia nervosa, were not found. This is consistent with the suggestion that bulimia is a diagnostic grouping distinct from these disorders.

Adult↗

PubMed1990

PET and neurobehavioral evidence of tetrabromoethane encephalopathy.

Organic solvents have been implicated in a number of neuropsychiatric disturbances, though physical and neurological exams are frequently negative. An individual with acute tetrabromoethane exposure was evaluated with positron emission tomography (PET), topographical electroencephalogram (EEG), and neurobehavioral assessment. Results suggest widespread central nervous system (CNS) dysfunction consistent with a solvent-induced encephalopathy.

Adult↗

PubMed1990

Glucose metabolic rate in normals and schizophrenics during the Continuous Performance Test assessed by positron emission tomography.

Local cerebral uptake of glucose labelled with fluorine-18 was measured by positron emission tomography in 13 patients with schizophrenia and 37 right-handed volunteers. Patients received no medication for a minimum of 31 days and a mean of 30 weeks. The subjects were administered the labelled deoxyglucose just after the beginning of a 32-minute sequence of blurred numbers as visual stimuli for the Continuous Performance Test. In normal controls, task performance was associated with increases in glucose metabolic rate in the right frontal and right temporoparietal regions; occipital rates were unchanged. Patients with schizophrenia showed both absolutely and relatively reduced metabolic rates in the frontal cortex and in the temporoparietal regions compared with normal controls.

Adult↗

PubMed1990

Positron emission tomographic measurements of pulvinar activity during an attention task.

Positron emission tomographic scans were recorded from human subjects following an object-identification task, one version of which required attentional selection and the other version of which did not. In one experimental session, the attention-demanding displays were presented in the left visual field and the nonattention displays were presented in the right visual field. In a second session, the sides of the displays were reversed. Analysis of the scans indicated that, averaged across the 2 sessions, the pulvinar showed greater glucose uptake when it was contralateral to the display of the selective attention task than when it was contralateral to the display of the nonattention task. The pattern of the data indicated that the degree of the attention task effect on pulvinar glucose uptake may differ between the hemispheres. In view of known connections between the pulvinar and cortical areas that mediate object identification, the present finding suggests that the pulvinar operates interactively with these cortical structures when an identification process demands selective attention.

Adult↗

PubMed1989

Increased temporal lobe glucose use in chronic schizophrenic patients.

Temporal lobe glucose metabolic rate was assessed in 21 off-medication patients with schizophrenia and 19 normal controls by positron emission tomography with 18F-deoxyglucose. Patients with schizophrenia had significantly greater metabolic activity in the left than the right anterior temporal lobe, and the extent of this lateralization was in proportion to the severity of psychopathology.

Adult↗

PubMed1989

Topographic EEG changes with normal aging and SDAT.

EEG topography was compared in patients with senile dementia of the Alzheimer's type (SDAT), aged normal controls, and young normal controls to assess regional differences. The square root of absolute power was determined for each frequency using a Fast Fourier Transform (FFT). The normal elderly group showed a reduction in all 4 frequency bands, delta, theta, alpha and beta, at each of 32 leads when compared to the young controls. Z-transformation of the data revealed differences in topography. Older normals showed significantly greater mid-parietal and left mid-temporal delta than the younger controls. A similar pattern was seen for theta activity. Elderly controls showed relatively less occipital alpha and greater mid-parietal alpha. Beta activity demonstrated these same significant topographic differences. The elderly/SDAT comparison was significant for delta only. SDAT patients were characterized by a marked delta asymmetry in temporal regions which was not seen in the elderly normals.

Aged↗

PubMed1989

Regional cerebral glucose metabolic rate in human sleep assessed by positron emission tomography.

The cerebral metabolic rate of glucose was measured during nighttime sleep in 36 normal volunteers using positron emission tomography and fluorine-18-labeled 2-deoxyglucose (FDG). In comparison to waking controls, subjects given FDG during non-rapid eye movement (NREM) sleep (primarily stages 2 and 3) showed about a 23% reduction in metabolic rate across the entire brain. This decrease was greater for the frontal than temporal or occipital lobes, and greater for basal ganglia and thalamus than cortex. Subjects in rapid eye movement (REM) sleep tended to have higher cortical metabolic rates than waking subjects. The cingulate gyrus was the only cortical structure to show a significant increase in glucose metabolic rate in REM sleep in comparison to waking. The basal ganglia were relatively more active on the right in REM sleep and symmetrical in NREM sleep.

Brain↗

PubMed1989

Platelet monoamine oxidase activity and life stress as predictors of psychopathology and coping in a community sample.

The present study, using a diathesis-stress model, attempted to confirm prior findings with platelet monoamine oxidase (MAO) activity and stress in a middle-aged, non-clinic population. One hundred and seventy-eight adult males from a statewide community club were tested for platelet MAO activity and stressful life events and were also given a variety of psychological measures of both psychopathology and psychosocial coping. The data were examined both for correlations across the total sample and for a comparison of high-risk groups (top and bottom 15% of MAO activity) with a middle MAO group. Low platelet MAO activity was related to a higher incidence of contact with mental health professionals, and more frequent use of alcohol and cigarette smoking. High MAO activity was related to higher levels of anxiety and somatization. High levels of stress were related to increased psychosocial problems reported for female and family members, higher scores on two schizophrenia-related MMPI scales (schizophrenia and paranoia subscales), but fewer idiosyncratic associations, elevated hypomanic, depression, and anxiety scores, increased alcohol use, and increased use of prescribed antianxiety and sedative medication. Neither MAO nor stress were related to current levels of psychosocial coping. Moreover, no interaction effects were uncovered for MAO activity and stress combined.

Adaptation, Psychological↗

PubMed1989

Positron emission tomography of the cerebellum in autism.

On the basis of neurological evidence that autistic patients have fewer Purkinje and granule cells in the cerebellum as well as vermal cerebellar hypoplasia, the authors tested the hypothesis that autistic patients have cerebellar hypofunctioning. They used positron emission tomography of the cerebellum with 18F-labeled 2-deoxyglucose to study seven autistic patients and eight age-matched control subjects. The results showed no significant difference in mean cerebellar glucose metabolism between the two groups, but all mean glucose rates of the autistic patients were either equal to or greater than those of the control subjects. The implications of these findings are discussed.

Adult↗

PubMed1988

Neuroleptic-induced hypothermia associated with amelioration of psychosis in schizophrenia.

Body temperature is a regulatory function of the hypothalamus. Recently, DeMet et al. (Society for Neuroscience Abstracts Vol 12, 1986) reported that apomorphine stimulation of dopamine autoreceptors caused a significant decrease in metabolic rate in the posterior heat-conserving area of the hypothalamus. The logical hypothesis to follow is that apomorphine administration should induce a decrement in body temperature; this in fact was demonstrated by Cutler et al. (Commun Psychopharmacol 3:375-382, 1979) in humans. It is well known that neuroleptics also disrupt thermoregulation (Clark: Neurosci Biobehav Rev 3:179-231, 1979) and affect dopamine autoreceptors. Therefore, eight chronic treatment-resistant schizophrenics underwent a 6-week single-blind trial of haloperidol and then a subsequent 6-week double-blind trial of clozapine. Both haloperidol and clozapine significantly lowered oral body temperatures relative to baseline washout temperatures. More interestingly, clozapine relative to haloperidol was found to induce a greater decrement in body temperature and was associated with greater clinical improvement. Possible confounding variables are discussed, as is the possible neurochemical basis for the amelioration of psychosis associated with hypothermia.

Adult↗

PubMed1988

Effects of amoxapine and imipramine on evoked potentials in the Continuous Performance Test in patients with affective disorder.

Twenty patients with major depressive disorder were studied with evoked potential (EP) topographic mapping after receiving placebo, imipramine, or amoxapine for 2 days in a random-assignment, double-blind design. Patients performed the Continuous Performance Test (CPT), a visual vigilance test. The stimuli were the digits 0-9, with 0 a target to be responded to with a button press. EPs were recorded from 32 channels and were averaged separately for detected and undetected targets and for false positives and correctly identified nontargets (no button press). Twenty-one normal controls were also tested. Amoxapine enhanced N120 amplitude in midline parietal and right parietal cortex where selective attention effects have been found to be greatest in studies of normal controls. Both amoxapine and imipramine enhanced differences in P200 between target and nontarget stimuli in comparison to placebo, with amoxapine differences again being greatest over midline parietal locations. CPT performance was significantly better on amoxapine than placebo.

Adult↗

PubMed1988

Biological vulnerability to depression: replication of MAO and evoked potentials as risk factors.

In previous work, we have reported that specific combinations of platelet (MAO) activity and evoked potential augmenting/reducing (AR) are associated with risk for affective disorders. This new study screened 271 college freshmen solely on MAO and AR and selected a sample with extreme values on both measures. These students were interviewed with the Diagnostic Interview Schedule and they completed a family history questionnaire and psychosocial scales. Following the previous work, the same MAO and AR combinations were related to the frequency of major depression and a family history of psychiatric disorder.

Adolescent↗

PubMed1987

Positron emission tomography assessment of effects of benzodiazepines on regional glucose metabolic rate in patients with anxiety disorder.

Patients with generalized anxiety disorder (n = 18) entered a 21-day, double-blind, placebo-controlled random assignment trial of clorazepate. Positron emission tomography with 18F-deoxyglucose was carried out before and after treatment. Decreases in glucose metabolic rate in visual cortex and relative increases in the basal ganglia and thalamus were found. A correlation between regional changes in metabolic rate and regional benzodiazepine receptor binding density from other human autopsy studies was observed; brain regions highest in receptor density showed the greatest decrease in rate.

Adult↗

PubMed1987

Positron emission tomography studies of basal ganglia and somatosensory cortex neuroleptic drug effects: differences between normal controls and schizophrenic patients.

Glucose metabolic rate in the basal ganglia, thalamus, and somatosensory cortex was examined in eight patients with schizophrenia before and after receiving neuroleptic medication. Basal ganglia metabolic rates were increased with medication: more on the right than on the left and more in putamen than caudate. The cortical anteroposterior ratio, an index of relative hypofrontality, was not affected by neuroleptics. The brain areas that were found to be altered by neuroleptics were selected for comparison between off-medication schizophrenics and controls. Metabolic rates in the basal ganglia tended to be low in patients with schizophrenia in comparison to 24 age- and sex-matched controls.

Adolescent↗

PubMed1987

Glucose utilization in the temporal cortex of affectively ill patients: positron emission tomography.

As temporal lobe dysfunction has been postulated in the affective disorders, the authors investigated glucose utilization in the temporal lobes of 13 affectively ill patients in comparison with 18 normal volunteer controls and 17 previously reported schizophrenic patients, following injections of fluorine 18-2-deoxy-D-glucose (FDG) during somatosensory stimulation to the right forearm. Using a boundary-finding algorithm to outline each temporal lobe, maximum glucose use relative to maximums elsewhere in the same positron emission tomography (PET) slice were calculated. In a small group of moderately to severely depressed patients, this relative measure was significantly reduced in the right (with a similar trend in the left) temporal lobe compared to normal volunteers and the other comparison groups. The lack of a significant increase in glucose utilization, measured either as a maximum or in relation to other areas in the PET scan slice, suggests that a temporal lobe activation or a seizure-like process is not generally occurring during active depressive phases of the illness.

Affective Disorders, Psychotic↗

PubMed1987

EEG topography of response to visual stimuli in generalized anxiety disorder.

EEG activity was recorded in 11 normal subjects and 19 patients with generalized anxiety disorder (GAD) at rest and while they were viewing a series of ten 4 sec continuous lights. Topographical cortical changes were assessed using 32-channel EEG power estimate maps. The percent changes from baseline to stimulation, for the first 5 and the last 5 light stimuli, were calculated and topographically mapped. Patients with GAD showed less decrease in alpha activity during the first 5 stimuli and more alpha activity during the last 5 stimuli in comparison to normal controls. Delta, theta, alpha, beta I and beta II did not show any difference during the resting periods. The topographical distribution of response to light was different in each group. Normal controls had a parieto-occipital reactivity and GAD patients a centro-parietal one with the maximum difference between the two groups being located in the occipital region. During the stimulation, beta I activity was decreased in controls and increased in patients. The diminishing reactivity of the patients is interpreted as a diminution of attention to external stimulation because of competing internal interferences. The pattern of regional reactivity suggests the importance of the centro-parietal and/or occipital regions in anxiety.

Adult↗

PubMed1987

[Long latency auditory evoked potentials: value of multichannel analysis and of high-resolution graphic mapping].

Auditory Evoked Potentials maps (AEP) were computed from 32 simultaneously recorded channels over both hemispheres using a linear interpolation algorithm. Reference electrode was extracephalic. Stimulus was a 781 Hz tone (intensity 70 dB HL, duration 256 msec). Average AEP were from 128 responses to randomly delivered stimuli. Direct current and frequencies over 50 Hz were removed by means of a digital filter (FFT). Results from 15 subjects showed before 120 msec a symmetrical response of AEP at vertex with left ear, right ear or binaural stimulation. Between 120 and 170 msec, maps of evoked responses were asymmetrical showing greater potentials over temporal areas contralateral to the stimulated ear.

Cerebral Cortex↗