Biomedical subjects

B Bogerts

Publications and source records attributed to B Bogerts.

At least 37 records · Page 2Linked to original sources

PubMed2001

Neuroanatomical studies on bipolar disorder.

Background Neuroimaging data showing structural and functional brain abnormalities in mood disorders suggest that brain alterations at the neurohistological level may underlie the macropathology seen by imaging in vivo. Aims To summarise recent post-mortem studies on affective disorders, with a focus on bipolar disorder. Method Literature review and discussion of results from volumetric, cyto-architectural and immunohistochemical analyses. Results Basal ganglia are smaller in patients with depression irrespective of diagnostic polarity. In addition, higher neuron numbers have been reported in the locus caeruleus of patients with bipolar disorder compared with those with unipolar depression. Patients with bipolar as well as unipolar illness show subtle structural deficits in the dorsal raphe. Histological data are consistent with a regional reduction in the synthesis of noradrenalin and serotonin, which appears to be compensated by antidepressants. Conclusion Preliminary results suggest that, aside from functional dysregulation, subtle structural abnormalities in the brain may contribute to the pathogenesis of mood disorders.

Journal Article↗

PubMed2001

Neuroanatomical studies on bipolar disorder.

BACKGROUND: Neuroimaging data showing structural and functional brain abnormalities in mood disorders suggest that brain alterations at the neurohistological level may underlie the macropathology seen by imaging in vivo. AIMS: To summarise recent postmortem studies on affective disorders, with a focus on bipolar disorder. METHOD: Literature review and discussion of results from volumetric, cyto-architectural and immunohistochemical analyses. RESULTS: Basal ganglia are smaller in patients with depression irrespective of diagnostic polarity. In addition, higher neuron numbers have been reported in the locus caeruleus of patients with bipolar disorder compared with those with unipolar depression. Patients with bipolar as well as unipolar illness show subtle structural deficits in the dorsal raphe. Histological data are consistent with a regional reduction in the synthesis of noradrenalin and serotonin, which appears to be compensated by antidepressants. CONCLUSION: Preliminary results suggest that, aside from functional dysregulation, subtle structural abnormalities in the brain may contribute to the pathogenesis of mood disorders.

Bipolar Disorder↗

PubMed2000

Delayed onset of late movement-related cortical potentials and abnormal response to lorazepam in catatonia.

Catatonia is a psychomotor syndrome with an inability to execute and terminate movements completely, leading consecutively to akinesia and posturing, which both respond almost immediately to benzodiazepines, i.e. gaba-potentiators like lorazepam. However, pathophysiological mechanisms of cortical motor and gaba-ergic dysfunction remain unclear. We therefore investigated movement-related cortical potentials (MRPs) and movement kinematics during a motor task before and after lorazepam. Ten akinetic catatonic patients were compared with 10 psychiatric (similar age, sex, medication, and underlying psychiatric disease but without catatonic syndrome) and 20 healthy controls. MRPs from frontal (F), central (C), and parietal (P) sites were recorded to obtain measures of early and late readiness potential and movement potential. Kinematic measures included parameters for amplitude of movements, peak velocity, average duration of movements, elevation angle, and angle velocity. The motor task consisted in self-initiated extension of the right index finger. All catatonic and psychiatric control patients received intravenous lorazepam (1mg), whereas healthy controls were subjected to a placebo-controlled (10 received lorazepam, 10 received placebo) double-blind study design.Catatonics showed a significantly delayed onset of late readiness and movement potential in central electrodes (Cz, C3) compared with psychiatric and healthy controls. This delayed onset correlated significantly with catatonic motor symptoms and movement duration. Lorazepam led to significantly stronger delays in onset of late readiness potential in left fronto-parietal (F3, C3, P3) electrodes in catatonic patients than in psychiatric and healthy controls. It is concluded that delayed latencies in late MRP components in catatonic patients may reflect their inability to execute and terminate movements completely. Differential and stronger response to lorazepam in catatonia suggests dysfunction in inhibitory control of cortical motor function with increased gaba-ergic sensitivity.

Adult↗

PubMed2000

Low and infrequent expression of nitric oxide synthase/NADPH-diaphorase in neurons of the human supraoptic nucleus: a histochemical study.

The gas nitric oxide is a messenger in brain signaling. In the hypothalamo-hypophyseal system nitric oxide is involved in the control of the expression and/or release of peptide hormones (corticotropin-releasing hormone, gonadotropin-releasing hormone, vasopressin and oxytocin). Nitric oxide synthase (NOS), the enzyme generating nitric oxide, is abundantly present in the magnocellular nuclei of the rat hypothalamus. Its localization in the human hypothalamus is less well studied. Hence, we investigated the anatomical distribution of neuronal nitric oxide synthase in the human supraoptic nucleus by use of immunohistochemical and enzyme histochemical techniques. The immunohistochemical localization of NOS was studied in 31 matched human hypothalami (13 control cases, eight depressed patients and ten schizophrenics). NADPH-diaphorase studies were carried out on seven additional hypothalami (three normal brains, four schizophrenics). Apparent inter-individual differences exist with regard to the occurrence of the enzyme in supraoptic neurons. In a majority of cases no immunostaining or histochemical reaction for the enzyme was observed. In seven cases (three controls, two schizophrenics, two depressives) a population of nitrergic nerve cells was seen in the dorsomedial part of the nucleus. This group of cells also stained for NADPH-diaphorase. Also, there were a few NOS-immunopositive neurons scattered throughout the nucleus. Additionally, thin NADPH-diaphorase positive fibers were observed to cross the nucleus. Our data show that, unlike the rat, the human supraoptic nucleus contains only a small number of nitrergic neurons. No correlation was found between the expression of the enzyme in supraoptic neurons and the psychiatric status of the patients.

Aged↗

PubMed2000

Right lower prefronto-parietal cortical dysfunction in akinetic catatonia: a combined study of neuropsychology and regional cerebral blood flow.

BACKGROUND: Catatonia is a psychomotor syndrome that can be characterized by behavioural, affective and motor abnormalities. In order to reveal further underlying pathophysiological mechanisms of psychomotor disturbances in catatonia we investigated neuropsychological function and regional cerebral perfusion (r-CBF) in a combined study. METHODS: Ten catatonic patients were investigated with Tc-99mECD brain SPECT and compared with 10 psychiatric (similar age, sex, medication and underlying psychiatric diagnosis but without catatonic syndrome) and 20 healthy controls. Neuropsychological measures included tests for general intelligence, attention, executive functions and right parietal visual-spatial abilities. Correlational analyses were performed between neuropsychological measures, catatonic symptoms and r-CBF. RESULTS: Catatonic patients showed a significant decrease of r-CBF in right lower and middle prefrontal and parietal cortex compared with psychiatric and healthy controls as well as significantly poorer performance in visual-spatial abilities associated with right parietal function. Correlational analysis revealed significant correlations between visual-spatial abilities and right parietal r-CBF only in psychiatric and healthy controls but not in catatonic patients. In contrast, attentional measures correlated significantly with motor symptoms, visual-spatial abilities and right parietal r-CBF in catatonia only but not in psychiatric or in healthy controls. CONCLUSION: Findings are preliminary but suggest right lower prefronto-parietal cortical dysfunction in catatonia, which may be closely related to psychomotor disturbances.

Adult↗

PubMed2000

[Juvenile experience and learning modulate the functional maturation of the brain: relevance for the genesis and therapy of mental disorders].

This article summarizes experimental data that indicate how juvenile experience and learning events modulate the functional maturation of the brain, shaping thereby the neuronal substrate for the development of intellectual and socio-emotional abilities. The fact that early experience occurs during early postnatal brain development, i.e. phases of elevated neuronal and synaptic plasticity, results in an "imprinting" of synaptic connectivity and neural circuitry in the infant brain. Results from experimental research in animal models support the hypothesis that impoverished intellectual stimulation and disturbance of the socio-emotional environment during early childhood may disturb the formation of functional brain pathways, in particular of the limbic circuits, which play a major role in emotion and learning. Such defective brain systems, representing neurofunctional "scars" in the brain, may be the neuronal basis of a variety of mental disorders and clinical symptoms caused by early stressful psychosocial environment. Ultimately, the goal will be to apply the knowledge gained to the development of biological and psychosocial intervention strategies by utilizing remaining plasticity of the adult human brain aimed at promoting human health, decreasing susceptibility and increasing resistance to disease.

Adult↗

PubMed2000

Functional dissociation between medial and lateral prefrontal cortical spatiotemporal activation in negative and positive emotions: a combined fMRI/MEG study.

The orbitofrontal cortex has been cytoarchitectonically and connectionally subdivided into a medial and a lateral part which are assumed to subserve distinct functions in emotional processing. However the exact spatiotemporal mechanisms of negative and positive emotional processing in medial and lateral orbitofrontal cortex remain unclear. We therefore investigated spatiotemporal orbitofrontal and prefrontal cortical activation patterns during emotional stimulation in a combined fMRI/MEG study. We investigated 10 healthy subjects, 5 women and 5 men. Positive and negative pictures from the International Affective Picture system (IAPS) were used for emotional stimulation, whereas neutral and gray pictures were taken as control conditions. fMRI/MEG measurements covered the whole frontal lobe and a time window between -2000 and +200 ms around motor responses (right index finger extension) associated with each picture. Positively and negatively correlated activities were determined in various prefrontal/frontal cortical regions in fMRI. Isocontour maps and single dipoles in MEG were analyzed in 50 ms time windows ranging from -2000 to +200 ms. Dipoles and fMR images were mapped on three-dimensional anatomical MRI so that anatomical localization of single dipoles and regional fMRI activity could be compared. Both negative and positive emotional conditions differed from non-emotional control conditions by strong orbitofrontal and lateral prefrontal activation as well as by the presence of early magnetic fields (-1700 to +1100 ms). Negative emotional processing was characterized by strong medial orbitofrontal activation and earlier (-1700 ms), stronger and more medially oriented orbitofrontal dipoles. In contrast positive emotional processing showed a rather strong activation in lateral prefrontal cortex with later (-1500 ms), weaker and more laterally oriented orbito and prefrontal dipoles. Negative emotional processing can be characterized by strong and early medial orbitofrontal cortical activation, whereas positive emotional processing showed rather later and weaker activation in lateral orbitofrontal/prefrontal cortex. Such a functional dissociation between medial and lateral orbito-frontal/prefrontal cortex during negative and positive emotional processing lends further support to the assumption of a functional subdivision in the orbitofrontal cortex.

Adult↗

PubMed2000

Disturbed gyrification of the prefrontal region in male schizophrenic patients: A morphometric postmortem study.

OBJECTIVE: The goal was to test the hypothesis that abnormalities of gyrification are present in the prefrontal region of postmortem brains from schizophrenic patients. METHOD: The authors compared the prefrontal regions in brains from 24 schizophrenic patients and 24 normal comparison subjects. The gyrification index, the ratio of inner and outer surface contours, was measured bilaterally in three different slices from each brain. Area measurements of gray and white matter were studied separately by planimetric analysis in the same sections. In addition, a gray-to-white-matter ratio and an asymmetry coefficient were computed. RESULTS: The mean gyrification index on the right side was significantly higher in the male schizophrenic patients than in the comparison men. The gyrification index of the female patients was not significantly different from that of the female comparison subjects. Analysis of area measurements revealed no significant differences. CONCLUSIONS: As gyrification is an ontogenetic stable feature unaffected by atrophic processes during aging, the gyrification abnormalities of the prefrontal region provide further evidence of the importance of a neurodevelopmental mechanism in the etiology of schizophrenia, at least in males.

Age Factors↗

PubMed1999

The pathomorphology of schizophrenia and mood disorders: similarities and differences.

In this article, post-mortem neurohistological and structural imaging studies of schizophrenia and mood disorders are briefly reviewed. In contrast to the large number of post-mortem studies on schizophrenia published during the last 20 years, very few histological studies of affective disorders are available. After commenting on CT and MRI studies, as well as on neuropathological findings on whole-brain size, cortex, frontal and temporal lobes, limbic system, basal ganglia, thalamus, brain stem, and cortical asymmetry, it is concluded that despite a broad overlap in structural findings in the so-called endogenous psychoses, heteromodal association cortex, limbic system, and structural asymmetry are more affected in schizophrenia, while subtle structural abnormalities in the basal ganglia, especially in the nucleus accumbens and in hypothalamic areas, might play a crucial role in mood disorders.

Affective Symptoms↗

PubMed1999

Cellular changes in rat brain areas associated with neonatal hippocampal damage.

The neonatal destruction of the ventral hippocampus was introduced as a model to recreate features of schizophrenia in the rat. While behavioral consequences of this intervention have been studied in detail, less is known about the cellular processes underlying the deviant behavior. We studied in rats (neonatally or adult lesioned, controls) brain areas receiving or not receiving hippocampal projections. The number of neurons and the expression of the cell markers L-ornithine decarboxylase, nitric oxide synthase/NADPH diaphorase, calretinin and GFAP were estimated. Reduced numbers of neurons and increased immunostaining for ornithine decarboxylase and nitric oxide synthase in the prefrontal, perirhinal and entorhinal cortex of neonatally but not adult lesioned rats or controls demonstrate persistent cellular changes after ventral hippocampus damage.

Aging↗

PubMed1999

Cortical sulcal enlargement in catatonic schizophrenia: a planimetric CT study.

To determine whether patients with catatonic schizophrenia have specific alterations in brain morphology, internal (ventricles) and external (frontal, temporal, parieto-occipital) components of the cerebrospinal fluid (CSF) spaces were examined morphometrically. Planimetric measurements of computed tomographic (CT) scans from 37 patients with catatonic schizophrenia, 28 patients with hebephrenic schizophrenia, and 39 patients with paranoid schizophrenia, all diagnosed according to DSM-III-R criteria, were compared with separate age- and sex-matched non-psychiatric control groups, respectively. The areas of the frontal sulci, the parieto-occipital sulci, the inter-hemispheric fissure, and the lateral and third ventricles were measured separately for the right and left hemispheres. Catatonic patients showed significant enlargements in almost all CSF spaces, especially in the left fronto-temporal area which, in addition, correlated significantly with illness duration. Hebephrenic patients showed selective enlargements in left temporal and left/right lower frontal cortical sulci, whereas paranoid schizophrenic patients showed no enlargements but significant correlations between left temporal cortical sulcal volume and illness duration. Alterations in temporal cortical areas were present in all three sub-types of schizophrenia. In addition to temporal alterations, hebephrenic schizophrenia was characterised by lower frontal (i.e. orbitofrontal) enlargement. Catatonic schizophrenia, the most severe sub-type with regard to clinical symptomatology and brain pathology, showed fronto-parietal cortical alterations.

Adult↗

PubMed1999

Impairment in visual-spatial function in catatonia: a neuropsychological investigation.

Catatonia is a psychomotor syndrome with motor and behavioral abnormalities which may be due to alterations in fronto-parietal cortical function. We therefore investigated neuropsychological tasks (attention, executive, visual-spatial, working memory) associated with frontal and parietal cortical function. Thirteen catatonic patients, diagnosed as catatonic according to criteria by Rosebush and Bush, were compared with 13 psychiatric non-catatonic controls (matched with regard to underlying psychiatric diagnosis, age, sex, and medication), and 13 age- and sex-matched healthy controls. Catatonics showed significantly poorer performances and different neuropsychological intercorrelation patterns in visual spatial object perception (VOSPobject) than psychiatric and healthy controls. In addition, we found significant correlations between catatonic symptoms, visual-spatial abilities, and attentional measures (i.e., d2, CWI). Catatonia was characterized by specific visual-spatial deficits which are related to attentional abilities and right parietal cortical function. The data suggest attentional-motor and fronto-parietal dysfunction in catatonia, a conclusion which should be considered as preliminary, however, due to the small sample size.

Adult↗

PubMed1999

Insulin-degrading enzyme in the Alzheimer's disease brain: prominent localization in neurons and senile plaques.

The anatomical distribution of insulin-degrading enzyme (IDE) was studied in normal and Alzheimer's disease (AD) human brains. By use of a monospecific, polyclonal antiserum against the enzyme we identified IDE antigen in multiple cortical and subcortical neurons. Glia did not show IDE immunoreactivity. In AD brains immunostaining appeared stronger than in controls and appeared not only in neurons but also in senile plaques. In a probable case of Lewy body variant of AD Lewy bodies in neurons of the Nuc. basalis of Meynert were immunopositive for IDE. Our anatomical data suggest that the enzyme is associated with typical neuropathologic hallmarks of AD and its expression appears up-regulated in some brain areas.

Adult↗

PubMed1999

Orbital frontal and amygdala volume reductions in obsessive-compulsive disorder.

BACKGROUND: Functional neuroimaging studies have implicated the frontal lobes and the hippocampus-amygdala complex in the pathophysiology of obsessive-compulsive disorder (OCD). These brain regions have not been well investigated in patients with OCD, however, using magnetic resonance imaging. METHODS: Volumes of the superior frontal gyrus, anterior cingulate gyrus, orbital frontal region, hippocampus, and amygdala were computed from contiguous magnetic resonance images in a sample of 26 patients with OCD and 26 healthy comparison subjects. RESULTS: Patients with OCD had significantly reduced bilateral orbital frontal and amygdala volumes compared with healthy comparison subjects and lacked the normal hemispheric asymmetry of the hippocampus-amygdala complex. Neither brain structure volumes nor asymmetry indices were significantly correlated with total illness duration or length of current OCD episode. CONCLUSIONS: Findings of reduced orbital frontal and amygdala volumes in patients implicate a structural abnormality of these brain regions in the pathophysiology of OCD. Absence of the normal hemispheric asymmetry of the hippocampus-amygdala complex in patients is consistent with an anomalous neurodevelopmental process.

Adult↗

PubMed1999

Catatonia as a psychomotor syndrome: a rating scale and extrapyramidal motor symptoms.

BACKGROUND: Catatonia was first described by Kahlbaum as a psychomotor disease with motor, behavioral, and affective symptoms. In keeping with this concept, we developed a rating scale for catatonia (Northoff Catatonia Scale [NCS]) with three different categories of symptoms (i.e., motor, behavioral, affective). Furthermore, the question of the relationship among catatonic symptoms, extrapyramidal motor symptoms, and neuroleptics was addressed in the present study. METHOD: 34 acute catatonic patients and 68 age-, sex-, diagnosis-, and medication-matched psychiatric control subjects were investigated on days 0, 1, 3, 7, and 21 with the NCS, with other already validated catatonia rating scales by Rosebush, Bush (BFCRS), and Rogers (MRS), as well as with scales for hypokinetic (SEPS) and dyskinetic (AIMS) extrapyramidal motor features. Validity and reliability of the new scale, factor analysis, correlational analysis, and differences between catatonic patients and psychiatric control subjects were statistically calculated. RESULTS: NCS showed high validity (i.e., significant positive correlations [p <0.0001] with the other scales, significant differences between catatonic and control subjects), high intra-and interrater reliabilities (r = 0.80-0.96), and high affective subscores. Factor analysis revealed four factors best characterized as affective, hypoactive, hyperactive, and behavioral. Catatonic scores in NCS correlated significantly with AIMS on day 0 and SEPS on days 7 and 21. There were no significant differences in catatonic (i.e., NCS, MRS, BFCRS) and extrapyramidal (i.e., AIMS, SEPS) scores between neuroleptically treated and untreated catatonic subjects. CONCLUSIONS: The following conclusions were drawn: (1) the NCS has to be considered as a valid and reliable rating instrument for catatonia; (2) catatonia can be characterized by psychomotor symptoms encompassing motor, affective, and behavioral alterations; and (3) extrapyramidal hyperkinesias like dyskinesias are apparently closely related to catatonic symptoms which, in general, seem to be relatively independent of previous neuroleptic medication.

Acute Disease↗

PubMed1999

The neuropathology of schizophrenic diseases: historical aspects and present knowledge.

In the first half of the century, histological abnormalities in the cortex and thalamus of schizophrenics were described. These findings, however, remained controversial and finally were widely forgotten. More recently, a large number of structural imaging studies convincingly showed subtle structural changes such as ventricular enlargement, cortical sulcal enlargement, and smaller hippocampi in a considerable proportion of schizophrenic patients. Many studies reported minor tissue abnormalities in limbic structures. Since the limbic system is anatomically and functionally interposed between the neocortical association areas and phylogenetically old hypothalamic and brain stem systems, limbic dysfunction may lead to a dissociation between cognitive activities and basic emotional reactions, thus, explaining some aspects of the psychopathology of schizophrenia. Reduced cortical asymmetry, lack of gliosis, and other findings support the idea of a disorder of early brain development; however, a progressive component also might be inherent.

Basal Ganglia↗

PubMed1999

Social behaviour in rats lesioned with ibotenic acid in the hippocampus: quantitative and qualitative analysis.

RATIONALE: Neonatal ibotenic acid lesion of the ventral hippocampus was proposed as a relevant animal model of schizophrenia reflecting positive as well as negative symptoms of this disease. Before and after reaching maturity, specific alterations in the animals' social behaviour were found. OBJECTIVE: In this study, social behaviour of ventral hippocampal lesioned rats was analysed. For comparison, rats lesioned either in the ventral hippocampus or the dorsal hippocampus at the age of 8 weeks were tested. METHODS: Rats on day 7 of age were lesioned with ibotenic acid in the ventral hippocampus and social behaviour was tested at the age of 13 weeks. For comparison, adult 8-week-old rats were lesioned either in the ventral or the dorsal hippocampus. Their social behaviour was tested at the age of 18 weeks. RESULTS: It was found that neonatal lesion resulted in significantly decreased time spent in social interaction and an enhanced level of aggressive behaviour. This shift is not due to anxiety because we could not find differences between control rats and lesioned rats in the elevated plus-maze. Lesion in the ventral and dorsal hippocampus, respectively, in 8-week-old rats did not affect social behaviour. CONCLUSIONS: The results of our study indicate that ibotenic acid-induced hippocampal damage per se is not related to the shift in social behaviour. We favour the hypothesis that these changes are due to lesion-induced impairments in neurodevelopmental processes at an early stage of ontogenesis.

Aggression↗

PubMed1999

Alterations of the dopaminergic and glutamatergic neurotransmission in adult rats with postnatal ibotenic acid hippocampal lesion.

In 6-week and 8-week-old rats (pre- and post-pubertally) with neonatal excitotoxic lesions of the ventral hippocampus with ibotenic acid (IBO), we have studied apomorphine-induced motor activity and glutamate and dopamine D1 and D2 binding sites in the hippocampus, striatum, nc. accumbens and frontal cortex as well as K+ -stimulated (3H)-D-aspartate release from hippocampal and frontal cortical slices. Specific glutamate binding was enhanced in the frontal cortex of 8-week-old IBO-treated animals, whereas that in other brain regions remained unchanged. Both D1 and D2 binding sites were downregulated in the striatum without changes in other brain structures. In 6-week-old rats, neither the glutamate nor the dopamine binding sites were altered. The amino acid release from hippocampal and frontal cortical slices of adult IBO treated rats was significantly decreased in comparison to controls, whereas in 6-week-old rats, no significant alterations were detectable. The additionally monitored motor activity was enhanced only in adult IBO-lesioned rats after apomorphine pretreatment. The present data are in agreement with the hypothesis of hyperactive dopamine and hypoactive glutamate systems in schizophrenia and are discussed in the light of schizophrenia-like behavioral changes in rats after postnatal hippocampal IBO lesion.

Age Factors↗