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Biomedical subjects

M S Buchsbaum

Publications and source records attributed to M S Buchsbaum.

At least 127 records · Page 7Linked to original sources
PubMed1987

Functional and anatomical brain imaging: impact on schizophrenia research.

A group of related new technologies has made it possible to study the brain's regional changes in metabolism, blood flow, electrical activity, and neurochemistry. Positron emission tomography (PET) produces slice images of radioisotope density--brain metabolism or receptor concentration can be quantitated. Studies in schizophrenia have indicated relative metabolic underactivity of the frontal lobes of schizophrenics. Decreased activity in the basal ganglia, which can be reversed with neuroleptic treatment, is also seen in schizophrenia. PET studies are in the early stages; standard methodology for isotope selection, task during tracer uptake, and quantitative analysis is still developing. Cerebral blood flow studies have shown similar patterns in the cortical surface. The electroencephalogram provides a short time resolution approach which can assess attention and arousal, but lacks some of the anatomic exactness and depth capabilities of PET. Magnetic resonance imaging furnishes anatomical images of gray and white matter previously unavailable with x-ray computed tomography. Advances in methodology and clinical studies with imaging are making neuroanatomic theories of schizophrenia more directly testable than ever before.

Attention↗
PubMed1987

Topographic mapping of EEG artifacts.

The topographic distribution of the artifacts of gritting the teeth, eye movements and blinking were studied in 32 channel recordings. In records from resting normal controls with all artifacts deleted, little EEG activity is present below 1.2 Hz or above 22 Hz. Gritting the teeth does not produce any apparent artifact in the alpha band or lower frequencies. However, it increases fast activity at 13 Hz and above across the scalp, especially in the temporal region bilaterally. The activity of eye movements was strongly present in low frequency maps in the frontal area and disappeared above 9 Hz. Blinking influences all four frequency bands greatly. Knowledge about the frequency range within the power spectrum and the areas on the map in which artifact appear is important in interpreting clinical EEG maps.

Adult↗
PubMed1986

Computed EEG topography of response to visual and auditory stimuli.

EEG activity was monitored in 15 normal subjects at rest and while they were given 10 sec continuous light or tone stimuli of different intensities. Topographical cortical changes were assessed using 16-channel EEG power estimate maps of the left hemisphere. Statistical analyses were performed using analyses of variance and t test, and the reactivity of the EEG, i.e., the percent change from the baseline state, in response to stimulation, was topographically mapped. Significant EEG reactivity was recorded in alpha, theta and delta bands without modification in the beta band. Stimulation-induced effects were maximum in the posterior part of the brain for both tone and light. The light effect was stronger than tone in the alpha band, but no differences in modality effect were recorded in the delta or theta band. Analysis of frequency bands within the alpha and theta band revealed a different pattern of reactivity with different regional involvements for tone and light. EEG reactivity occurred mainly in 7-10 Hz frequency bands with no significant change in 5, 6, 11, 12 and 13 Hz. Reactivity was maximal in the temporal area during tone for 7-9 Hz and in the occipital region during light for 8-10 Hz. The 8 and 9 Hz frequency bands showed increased blocking with an increase in stimulus intensity. Taken together, the results indicate that visual and auditory stimuli both produce an EEG amplitude decrease which is greatest over their respective primary sensory cortex.

Adult↗
PubMed1986

Topographic differences between normals and schizophrenics: the N120 evoked potential component.

Topographic differences in evoked potentials were measured in 20 off-medication chronic schizophrenics and 24 normal controls. Four intensities of brief electrical shocks were administered to the subject's right forearm in a random order at 1-second intervals. Evoked potentials (EPs) were recorded from the scalp over the left hemisphere. The EP data from 16 left hemisphere leads were used to generate EP maps of brain response for individual subjects. The maps were normalized by z transformation. Group mean maps of EP activity and unpaired t tests were then computed. Normals showed strongly localized activity in the pre- and postcentral gyri, with increasing intensity resulting in the attenuation of parietal response. Schizophrenics showed more diffuse EP activity which did not vary with intensity. Significant differences between normals and schizophrenics were found for all four intensities in posterior frontal and anterior parietal cortex. This is consistent with the findings of small EPs reported by others in the somatosensory, visual and auditory modalities.

Adult↗
PubMed1986

Brain imaging in the search for biological markers in affective disorder.

Positron emission tomography with 18fluorodeoxyglucose provides the possibility of obtaining detailed noninvasive images of the brain's metabolic rate in patients with affective disorder. The close correspondence between brain work and metabolic rate allows the researcher to assess brain functional activity and its changes with drug treatment or even sleep. Initial studies have revealed that the metabolic rate in frontal cortex relative to parietal and occipital cortex is lower in patients with bipolar affective disorder than in normal controls. A small sample of unipolar patients showed a relatively higher frontal cortex metabolic rate than normal controls. Bipolar patients also showed metabolic rates in the basal ganglia relative to whole slice metabolism to be low in comparison to normal controls. Antidepressant drugs appeared to have their greatest effects in the frontal lobes.

Antidepressive Agents↗
PubMed1985

Attention dysfunction and psychopathology in college men.

Four hundred college men were screened on a measure of vigilance, the Continuous Performance Test (CPT). The individuals with good and poor attention (the upper and lower 5% of the CPT score distribution) were compared on multiple measures of psychiatric disturbance, cognition, and psycho-physiologic function. The attention dysfunction group (lower 5%) had a higher incidence of symptoms of hyperactivity both in childhood and as adults, but had no higher incidence of other psychopathology as assessed with either the Research Diagnostic Criteria or the Minnesota Multiphasic Personality Inventory. Cognitive differences between the lower and upper CPT groups, including differences on Wechsler Adult Intelligence Scale subtests, the Stroop test, reaction time, and evoked potentials, substantiated an attention dysfunction syndrome. Thus, attentional dysfunction in young adults seems more closely linked to hyperactivity than to current psychopathology.

Adolescent↗
PubMed1985

Topographic EEG changes with benzodiazepine administration in generalized anxiety disorder.

The regional cerebral effects of an anxiolytic (clorazepate) in 20 patients with generalized anxiety disorder were assessed using 16-channel electroencephalogram (EEG) power spectral estimate maps of the left hemisphere. Patients were studied with double-blind random assignment to placebo or drug and were assessed at baseline, day 7, and day 14 with EEG and Hamilton Anxiety Ratings. Ten age- and sex-matched normal controls were also tested. Hamilton Anxiety Ratings were decreased significantly more in the drug group than in the placebo group. Topographic maps of EEG activity revealed decreases in occipital alpha and parietal delta, together with increases in posterior frontal (central EEG leads) and parietal beta. Decreases in delta are consistent with a lack of sedation; the reciprocal beta increases in parietal cortex are similarly consistent. This pattern of regional EEG changes in the direction of alert attentiveness, together with individual differences, observed in frontal/parietal and occipital alpha activity, suggests the importance of at least these two cortical regions for anxiolytic action. Differences between patients with generalized anxiety disorder and normals were restricted to the occipital and temporal regions. These results suggest the importance of multilead recording in assessing EEG correlates of drug action.

Adult↗
PubMed1985

Normal pain sensitivity in patients with panic disorder.

The pain sensitivity of 18 patients with panic disorder and age- and sex-matched controls was assessed by signal detection analysis. The authors failed to demonstrate any difference in pain sensitivity between the two groups. The relationship between state anxiety, as assessed by the Spielberger scale, and pain in panic patients tended to be in the opposite direction from that in normals.

Adult↗
PubMed1985

Clinical correlates of decreased anteroposterior metabolic gradients in positron emission tomography (PET) of schizophrenic patients.

The finding in schizophrenic patients of a reversal of the normal frontal to posterior pattern of brain metabolic activity with positron emission tomography (PET) is of interest, but its relevance to psychopathology is unknown. Using PET, the authors studied 21 patients with chronic schizophrenia and 21 age- and sex-matched control subjects. Although eight of the 21 patients and only one of the control subjects showed a relatively lower anteroposterior metabolic gradient, no clinical correlates of this finding were noted. In addition, cerebral atrophy, as determined by CAT scan, was not associated with this aberrant metabolic pattern.

Adolescent↗
PubMed1984

Anteroposterior gradients in cerebral glucose use in schizophrenia and affective disorders.

Local cerebral uptake of deoxyglucose labeled with fluorine 18 was measured by positron emission tomography in 16 patients with schizophrenia and 11 patients with affective disorder. Patients received no medication a minimum of 14 days and an average of 39.8 days. The subjects were administered the deoxyglucose 18F just before receiving a 34-minute 1/s series of unpleasant electrical stimuli to the right forearm while resting with eyes closed in a darkened, acoustically attenuated psychophysiologic testing chamber. Following monitored stimulation in the controlled environment, subjects were scanned and images converted to values of glucose use in micromoles per 100 g per minute according to Sokoloff's model. Data were analyzed with a four-way analysis of variance (ANOVA) with independent groups (normals, schizophrenics, and affectives) and repeated measures for slice level (supraventricular, midventricular, and infraventricular), hemisphere (right, left), and anteroposterior position (four sectors). Both normal subjects and patients showed a significant anteroposterior gradient in glucose use with highest values in the frontmost sector. Patients both with schizophrenia and with affective illness showed less of an anteroposterior gradient especially at superior levels, which was statistically confirmed by ANOVA. Absolute glucose levels in patients, which were actually higher in posterior regions rather than lower in frontal regions, were the largest contributors to the effect. Neither group differences in whole brain glucose use nor left-right asymmetries reached statistical significance. These results are consistent with our earlier reports of a relative hypofrontal function in schizophrenia compared with controls. This report extends this finding to affective illness, sharing a lack of diagnostic specificity with many biologic measures.

Adult↗
PubMed1984

Positron emission tomographic image measurement in schizophrenia and affective disorders.

Two analytical methods for assessing regional glucography with positron emission tomography were compared in 16 patients with schizophrenia and 11 patients with affective disorders. Patients were off all medication a minimum of 14 days and an average of 39.8 days. The subjects were administered fluorine-18-labeled 2-deoxyglucose just before receiving a 34-minute one-per-second series of unpleasant electrical stimuli to their right forearm while resting with their eyes closed in a darkened, acoustically attenuated psychophysiological testing chamber. Following monitored stimulation in the controlled environment, the subjects were scanned and the images were converted to values of glucose use in micromoles per 100 grams per minute, according to Sokoloff's model. Data were analyzed by a four-way analysis of variance (ANOVA) for independent groups (normal subjects, schizophrenic patients, and patients with affective disorders) and for repeated measures of slice level (supraventricular, midventricular , and infraventricular ), hemisphere (right, left), and anteroposterior position (four sectors). Normal individuals and patient groups both showed a significant anteroposterior gradient in glucose use, with the highest values in the sector farthest to the front. Patients with schizophrenia and those with affective illnesses showed less of an anteroposterior gradient than normal individuals, especially at superior levels, which was statistically confirmed by ANOVA. Neither the group differences in whole-brain glucose use nor the left-right asymmetries reached statistical significance. A second technique, involving reconstruction of the lateral cortical surface, also revealed differences between schizophrenics and normal individuals in the superior frontal cortex. These results are consistent with our earlier reports of a relative hypofrontal function in schizophrenia compared with controls; they also extend the finding to the affective illnesses, the other group of major psychoses.

Adult↗
PubMed1984

The Genain Quadruplets 25 years later: a diagnostic and biochemical followup.

A biological and clinical followup of the Genain Quadruplets was initiated as a multilaboratory collaborative effort at the National Institute of Mental Health (NIMH). The quadruplets are 51-year-old monozygotic women previously studied with a battery of psychological and physiological tests 25 years ago at the NIMH. The present article (the first of a series of three) details the clinical history and course of the schizophrenic illness in each of the quadruplets and describes the biochemical measures determined. The findings of elevated urinary phenylethylamine excretion, decreased plasma dopamine-beta-hydroxylase activity, and increased alpha-adrenergic receptor concentrations in all quadruplets warrant further genetic studies.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1984

The Genain Quadruplets: psychological studies.

A series of behavioral studies is reported on the Genain Quadruplets. These monozygous women, all of whom have suffered or are suffering from schizophrenia, were studied previously at the National Institute of Mental Health (1955-1958) and were the subject of an extensive report by Rosenthal (1963). Although the Genains are genetically identical, the expression of the schizophrenic disorder is unequal among the quads, and this circumstance has led to speculation about the relative contributions of nature and nurture (or diathesis and stress in Rosenthal's terminology) in the development of this disease. Two goals were pursued in this investigation: one concerned a comparison of the status of the Genains in 1981 as compared with 1958; the other concerned whether data from the armamentarium of newer behavioral and neurobiological techniques invented and employed since 1958 might shed some light on the unequal expression of schizophrenia among the quadruplets. We conclude that the Genains are functioning about as well as they ever have in their adult lives, and scores on attentional tests show improvement as compared to 1958 measures. This is probably attributable to the medication (primarily neuroleptics) and other supportive treatments they have received over the years. With respect to the varying degrees of illness seen in the Genains, scrutiny of the biochemical, physiological, neuroradiological, immunogenetic, and behavioral test data leads to speculation that certain unique biochemical findings interacting with differing types and amounts of cerebral pathology constitute a major cause of the variable expression of the schizophrenic diathesis.

Antipsychotic Agents↗
PubMed1984

The Genain Quadruplets: electrophysiological, positron emission, and X-ray tomographic studies.

Four 51-year-old monozygotic quadruplets concordant for schizophrenia, originally studied at the National Institute of Mental Health 25 years ago, were restudied with topographic electroencephalography (EEG), evoked potentials (EPs), computed tomography (CT scans), polysomnographic sleep recordings, and positron emission tomography (PET) with 18F-2-deoxyglucose. EEG and EP findings were consistent with those from other groups of patients with schizophrenia and showed great similarity within the quadruplets. CT scans revealed uniformly small lateral ventricles. PET scans replicated earlier findings of relatively low glucose use in the frontal lobes but did not show strong familial concordance.

Brain↗
PubMed1984

Effects of antidepressants on skilled performance.

Effects of amitriptyline 50 mg, desipramine 100 mg, and zimelidine 200 mg alone and in combination with ethanol 0.8 g/kg were investigated in healthy, male volunteers. Amitriptyline increased body sway and impaired tracking as well as information processing. It had an additive deleterious pharmacodynamic interaction with ethanol. Desipramine and zimelidine were free of adverse effects on performance and did not have significant interactions with ethanol. The dose of ethanol used in the present study did not inhibit biotransformation of the antidepressants.

Adult↗