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At least 145 records · Page 8Linked to original sources
PubMed1989

Effect of adafenoxate on different rat brain structures monoamine oxidase activity in vitro.

1. The effect of the nootropic drug adafenoxate on monoamine oxidase (MAO) activity in rat brain cortex, striatum, hypothalamus and hippocampus has been studied using the following substrates: tyramine (total MAO), serotonin (MAO A) and beta-phenylethylamine (MAO B). 2. In a series of increased concentrations (from 5 x 10(-4) up to 1 x 10(-5) M) adafenoxate inhibits total MAO, MAO A and MAO B in the brain structures studied. 3. The adafenoxate IC50 values obtained illustrate its inhibitory properties and its lack of selectivity toward MAO in the brain structures isolated. 4. The results of our research prove the participation of MAO in the mechanisms through which adafenoxate affects the brain monoaminergic systems and realises its central effects.

Animals↗
PubMed1994

Evaluating and validating two methods for estimating brain structure volumes: tessellation and simple pixel counting.

Developments in imaging technology have made three-dimensional visualization of internal brain structures possible with excellent resolution. Since improved visualization implies improved measurement, these advances hold promise to more accurately measure the volumes of internal structures. As new technologies and techniques emerge, evaluating the relative benefits of measurement methods becomes necessary. We compared and evaluated two methods of estimating volumes from images of brain structures. One method counted pixels within a region of interest, while the other method tessellated the surface between tracings on adjacent slices. Our study assessed both measurement error for true phantom volumes and method disparity for in vivo structures in a randomly selected sample of subjects (n = 100). For our comparisons, we focused on the temporal lobe, ventricular system, and hippocampus. Bias, independence of measurement errors and maximal discrimination of individual differences are properties that are relevant to validating and evaluating measurements of cerebral structure. Pixel counting proved to be the more robust of the two methods, being less sensitive to nuisance-interactions between size of object, shape, and slice thickness. Clinical and research applications of imaging techniques may have distinctive but overlapping needs when evaluating and validating new developments in imaging.

Adult↗
PubMed1994

Brain structure changes in schizophrenics with high serum titers of antibodies to herpes virus.

We compared five indices of brain structure between two groups of schizophrenics, namely, those with high and normal levels of antibody in the serum to herpes virus. Eleven 'immuno-positive' and 21 'immuno-normal' subjects obtained from a concomitant study of serum IgG antibody to viruses underwent magnetic resonance imaging (MRI) utilizing a 1 Tesla magnet and 8 mm thick slices. We measured ventricle-brain ratio (VBR), 3rd ventricle width, cortical atrophy, area of corpus callosum, and frontal lobe area. The differences between groups were assessed by t-test and chi-square analysis. Eight of 11 immuno-positives compared to 7 of 21 immuno-normals showed evidence of cortical atrophy (chi 2 = 4.49, p < 0.03). The immuno-positives had smaller left frontal area (mean + s.d = 125.69 + 21.30 versus 143.76 + 19.84, t = 2.07, p < 0.05) and larger 2nd quadrant of the corpus callosum (mean + s.d. = 1.58 + 0.39 versus 1.27 + 0.52, t = 2.68, p < 0.01). The right frontal area also was smaller in immuno-positives but not significant. VBR, 3rd ventricle and the 1st, 3rd and 4th callosal quadrants did not differ between the groups. We conclude that high antibody titers to herpes found in the sera of some schizophrenics might reflect an earlier pathogenetic process that affected brain development. Further studies of antibodies in CSF and brain structure in these or similar subjects and those suspected to be exposed to viral infections in utero should be vigorously pursued to obtain definitive evidence for this hypothesis.

Adult↗
PubMed1988

Effects of ECT on brain structure: a pilot prospective magnetic resonance imaging study.

The authors describe a pilot prospective investigation of the effects of ECT on brain structure using magnetic resonance imaging (MRI). In nine patients with major depression, a course of ECT produced no acute changes in brain structure according to blind raters' assessments of cortical atrophy and global comparison of pre- and post-ECT studies. There were also no significant changes in the ventricle-brain ratios. Pre-ECT brain abnormalities were common in these patients yet were also unaffected by ECT. Future MRI studies of ECT should include more subjects and should address long-term changes and subtle brain abnormalities.

Adult↗
PubMed2006

The effects of acute and chronic administration of corticosterone on rat behavior in two models of fear responses, plasma corticosterone concentration, and c-Fos expression in the brain structures.

The aim of this paper was to examine changes in rat emotional behavior, and to find the brain structures, which are involved in the mediation of behavioral effects, related to the repeated administration of glucocorticoids. The effects of acute and chronic pretreatment of rats with two doses of corticosterone (5 and 20 mg/kg) were analyzed in two models of fear responses: neophobia-like behavior in the open field test, and freezing reaction in the conditioned fear test. Behavioral effects of repeated glucocorticoid administration were compared to changes in blood total corticosterone concentration, and expression of immediate early gene (c-Fos) in brain structures. It was found that acute administration of corticosterone (90 min before tests) enhanced rat exploratory behavior, and decreased freezing reaction. On the other hand, repeated administration of corticosterone (for 25 days, the final injection 90 min before contextual fear conditioning training) decreased plasma corticosterone concentration, inhibited exploratory behavior, enhanced freezing responses on retest and produced a complex pattern of changes in c-Fos expression, stimulated by exposure of rats to the aversively conditioned context. Aversive context induced c-Fos in the magnocellular neurons of the hypothalamic paraventricular nucleus (mPVN), dentate gyrus (DG), cingulate cortex area 1 (Cg1), and primary motor cortex (M1). In rats chronically treated with corticosterone this effect was attenuated in the mPVN and DG, enhanced in the M1, and additionally observed in the CA1, CA2 layers of the hippocampus, and in the central nucleus of amygdala (CeA), in comparison to control animals not subjected to contextual fear test. In sum, the present data suggest that chronic corticosterone treatment enhances the activity of primary motor cortex and CeA with subsequent improvement of memory of aversive events, and simultaneously stimulates a negative feedback mechanism operating in PVN with ensuing decrease in blood corticosterone concentration.

Animals↗
PubMed1978

[Study of the constituent proteins of brain structures by the technic of electrophoresis in a continuous polyacrylamide gel gradient in capillaries].

The author compared the protein composition of the brain structures (premotor zone of the cortex, CA3 are of the hyppocampus, the caudate nucleus, the frontal lobe of the cerebellum) in rats by electrophoresis in the continuous gradient of polyacrylamide gel pores in capillaries. The method used proved to possess a much greater resolving capacity in comparison with electrophoresis in the homogeneous gel concentration; no differences could be revealed in the protein composition of the brain structures under study.

Animals↗
PubMedDate not supplied

[Activity of nonspecific succinic semialdehyde reductase in brain structures of long- and short-sleeping rats].

Some differences were found in the kinetic parameters of nonspecific succinic semialdehyde reductase in the brain structures of rats with different tolerance to alcohol. Ethanol injection was followed by diverse changes in the parameters under study depending on the brain structure and tolerance of the animal to alcohol. A more pronounced effect of alcohol was observed in the basal ganglia of the long-sleep rats and in the hemispheres and brain stem of the short-sleep rats.

Animals↗
PubMed1997

Schizophrenia as a chronic active brain process: a study of progressive brain structural change subsequent to the onset of schizophrenia.

Brain structural deviation is known to be present in chronic patients with schizophrenia when compared with normal age-matched individuals. While the assumption is that these differences are based on a neurodevelopmental disturbance, whether they are static or continue to change throughout the disease process remains unknown. The following report describes a prospective follow-up study of first episode cases of schizophrenic illness. Analyses of MRI evaluations on an approximate annual basis for a minimum of four years are presented on 50 patients and 20 controls. Computer-assisted image analysis measuring the volume of several brain regions, using the program ANALYZE (Mayo Clinic), was performed on all scans. Patients were compared with controls for the rate of change over time in size of structures. No differences were found for the volumes of the caudate nucleus, temporal lobes, or hippocampus; and no changes in the degree of cerebral laterality were detected. However, there was a significant difference in the rate of change in the overall volumes of left and right hemispheres (P < 0.0004 and 0.001, respectively), right cerebellum (P < 0.02) and area of the isthmus of the corpus callosum (P < 0.05). The left cerebral ventricle had significantly greater enlargement over time when measured on coronal slice sequences (P < 0.02), but was not detected by axial views. These findings suggest that a subtle active brain process may be continuing through the first few years of a schizophrenic illness causing greater than the normal adult cortical deterioration. Further studies using other methods of image analysis and over a longer period of time are needed to determine the course and nature of this biologic process.

Adult↗
PubMed1982

[Neurospecific antigen D in the postnatal ontogeny of rat brain structures].

The time course of antigen D similar to well-known neurospecific proteins 14-3-2 and antigen alpha was studied during postnatal ontogenesis of brain structures of Wistar rats: Cross immunoelectrophoresis was made use of to measure the content of antigen D in the visual cortex, hippocamp and nucleus caudatus of rats aged 7, 14, 21 and 30 days and 1 year. Changes in the levels of two antigen D components, slow- and fast-migrating (SMC and FMC) were recorded to show that their content in the test structures increased most intensely from the 14th to the 21st day of postnatal development. In all the brain structures of tendency was recorded towards the increased SMC/FMC ratio during postnatal ontogenesis, that may point to an important role of FMC for bain functions in maturing and adult animals.

Aging↗
PubMed1980

Reflectance of rat brain structures mapped by an optical fiber technique.

A method to detect differences in reflectance as a pair of glass fibers is advanced through various brain structures at a constant speed is described. The system has been used to develop a technique for accurate and easy placement of electrodes or cannulae into a limited brain region. The probe consisted of two thin (50 micrometer in diameter) glass optic fibers. A 5 W lamp was used to transmit light down one of these fibers. The relative intensity of light reflected from brain tissue into the other optic fiber was monitored with a photomultiplier and ink-writing recorder. Different brain structures were shown to vary in the amount of reflectance, with white matter having much higher reflectance than gray matter. It was demonstrated in a total of 239 penetrations that the patterns of successive changes in the reflected light response, as the probe was lowered into the brain, was characteristic for each frontal plane. The probe may additionally be itself used as an electrode if plated with silver.

Animals↗
PubMed1990

The effect of fenfluramine on the thyrotropin-releasing hormone (TRH) content in the rat brain structures and lumbar spinal cord.

The effect of fenfluramine (20 mg/kg i.p.) was studied on the thyrotropin-releasing hormone (TRH) content in several brain structures and the ventral part of the lumbar spinal cord of the rat. The effect of fenfluramine on the concentration of 5-hydroxytryptamine (5-HT) in some brain structures and the lumbar spinal cord was also examined. It was found that fenfluramine had no effect on the TRH level in the hypothalamus, hippocampus, occipital cortex, septum, nucleus accumbens and ventral part of the lumbar spinal cord, though the drug produced a profound depletion (by more than 60%) of 5-HT in the hypothalamus, nucleus accumbens, striatum and lumbar spinal cord. On the other hand, fenfluramine significantly increased the TRH content in the striatum, this effect was completely abolished by citalopram (20 mg/kg i.p.) or metergoline (10 mg/kg i.p.) Citalopram also prevented the fenfluramine-induced depletion of the striatal 5-HT. These results indicate a separate neuronal storage of TRH and 5-HT in the structures (ventral part of the lumbar spinal cord, nucleus accumbens, septum) in which the peptide and indoleamine coexist in 5-HT neurons. They also suggest that the fenfluramine-induced increase in the striatal TRH concentration is due to 5-HT release and stimulation of 5-HT receptors.

Animals↗
PubMedDate not supplied

Selective action of decimeter waves on central brain structures.

To study the sensitivity of some central brain structures to the action of an electromagnetic field of decimeter waves (EMF of DW) a dynamic investigation of single unit activity was undertaken. Neurons of the hippocampus and hypothalamus with an excitatory type of response were found to have the greatest reactivity to EMF of DW. Neurons of the mesencephalic reticular formation and of the specific nuclei of the thalamus had mostly an inhibitory type of response. The number of neurons responding actively to EMF of DW and the number of inactive neurons varied depending on the energy density of the EMF.

Animals↗
PubMed2003

Progressive structural brain abnormalities and their relationship to clinical outcome: a longitudinal magnetic resonance imaging study early in schizophrenia.

BACKGROUND: Many studies have shown that structural brain abnormalities in schizophrenia are already present by the time of index evaluation of first-episode patients. However, whether these abnormalities progressively worsen during the subsequent course of the disorder remains unresolved. METHODS: To study the longitudinal progression of structural brain abnormalities, high-resolution multispectral magnetic resonance images obtained on 73 recent-onset schizophrenic patients and 23 controls were analyzed using state-of-the-art, well-validated, and highly reliable neuroimaging tools. The mean duration between initial and follow-up MRIs was 3 years. Repeated-measures analysis of covariance was carried out to determine (1) whether brain volume changes differed between patients and controls and (2) the significance of regional brain changes on functional outcome in schizophrenia. RESULTS: We found accelerated enlargement in cortical sulcal cerebrospinal fluid spaces early in the course of schizophrenia. Instead of the usual trajectory of volume enlargement, patients showed progressive reduction in frontal lobe white matter volume. A reciprocal increase in frontal lobe cerebrospinal fluid volume also occurred at a more rapid rate in patients than in controls. In keeping with most of our a priori hypotheses, patients with poor outcome had greater lateral ventricular enlargement over time than patients with good outcome. Progressive decrement in frontal lobe white matter volume and enlargement in frontal lobe cerebrospinal fluid volume were associated with greater negative symptom severity. Reductions in frontal lobe gray and white matter volumes correlated with poorer executive functioning. CONCLUSIONS: There are ongoing changes in the brains of schizophrenic patients during the initial years after diagnosis despite ongoing antipsychotic drug treatment. These progressive changes seem to be most evident in the frontal lobes and to correlate with functional impairment. Disruptions in neurodevelopment or neural plasticity may act alone or in combination to bring about these progressive brain deficits in schizophrenia.

Adult↗
PubMedDate not supplied

[Epileptogenic effect of quinolinic acid on the brain structures].

Data on the electrolytic lesions of the brain structures (striatum, dorsal hippocampus, amygdaloid complex) in rats suggest a trigger role of striatum in the formation of quinolinic acid (30 micrograms, intracerebroventricularly)--induced seizures. EEG recording also supports this conclusion.

Amygdala↗
PubMed1995

Effect of compound 48/80 on mast cells and biogenic amine levels in brain structures and on corticosterone secretion.

The effect of compound 48/80, given intracerebroventricularly, on mast cells (MC) and histamine, serotonin and noradrenaline levels in the hypothalamus, thalamus and hippocampus as well as on corticosterone secretion was investigated in rats. A relatively high amount of mast cells was found in the thalamus, a very low in the hypothalamus and almost none in the hippocampus. Compound 48/80 (1 and 5 micrograms) induced MC degranulation, a significant increase in corticosterone secretion and diminution of the thalamic histamine level. The drug also elicited small biphasic changes in histamine level in the hypothalamus and moderately increased serotonin turnover in the brain structures studied, but did not affect noradrenaline level in those structures. These results indicate that brain MC contain a significant amount of histamine, but not serotonin. Compound 48/80 releases histamine from MC, but does not markedly influence neuronal biogenic amines in the brain structures involved in regulation of the hypothalamic-pituitary-adrenal axis.

Animals↗
PubMed1991

Clinical, neuropsychological, and brain structural correlates of smooth-pursuit eye tracking performance in chronic schizophrenia.

The relation of smooth-pursuit eye tracking dysfunction to neuropsychological performance, brain structural anomalies, and clinical state was examined in a sample of 61 patients with chronic schizophrenia. No association was found between impaired pursuit oculomotion and measures of chronicity or clinical state. Likewise, no association emerged between eye-tracking integrity and brain structural anomalies. Patients with dysfunctional eye tracking were more likely to have impaired performance on tests that assess frontal lobe functioning. In addition, negative symptoms and a relative absence of positive symptoms. Because negative symptoms are often found among patients with frontal lobe impairment, their association with abnormal eye tracking provides converging support for the hypothesis that the cortical locus of deviant smooth-pursuit eye tracking is in the frontal lobes.

Adolescent↗
PubMed1987

A computer-aided three-dimensional reconstruction of brain structures using high level computer graphics.

This paper describes how line drawings and continuous tone shaded images of a three-dimensional solid model of a brain structure are generated using a powerful general purpose computer graphics package. The model is built from a series of serial sections. We developed a software interface to convert the data entered by a section oriented way into a brain structure oriented file. We point out particularly the modular approach which consists of separating the tasks on small microcomputers or on bigger machines according to their computing cost. An example of a thalamic structure in a stereotaxic referential is presented.

Animals↗
PubMed1991

EEG laterality in the era of structural brain imaging.

Bilateral EEG recording is a common practice when brain laterality needs to be assessed in cognitive neurophysiology and psychiatry research. Its precision and validity remain uncertain. With structural brain imaging methods, it is possible to examine EEG electrode placements according to the 10-20 system and the validity of inferences made on derived data. Frequent sources of placement errors are examined along with important factors that contribute to EEG imbalance. Examples are mentioned where asymmetries of EEG/ERP caused by cranial and parenchymal brain asymmetries may be mistaken for cognition-related laterality changes. Because external skull landmarks are not reliable predictors of cranial and parenchymal brain asymmetries, laterality assessment cannot be guaranteed by the 10-20 system. Consequently, a return, on a case-to-case basis, to nonstandard montages, assisted by structural brain imaging is seen as an acceptable alternative.

Brain↗