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At least 433 records · Page 24Linked to original sources
PubMed2006

A meta-analysis of structural brain abnormalities in PTSD.

This series of meta-analyses examined structural abnormalities of the hippocampus and other brain regions in persons with PTSD compared to trauma-exposed and non-exposed control groups. The findings were significantly smaller hippocampal volumes in persons with PTSD compared to controls with and without trauma exposure, but group differences were moderated by MRI methodology, PTSD severity, medication, age and gender. Trauma-exposed persons without PTSD also showed significantly smaller bilateral hippocampal compared to non-exposed controls. Meta-analyses also found significantly smaller left amygdala volumes in adults with PTSD compared to both healthy and trauma-exposed controls, and significantly smaller anterior cingulate cortex compared to trauma-exposed controls. Pediatric samples with PTSD exhibited significantly smaller corpus callosum and frontal lobe volumes compared to controls, but there were no group differences in hippocampal volume. The overall findings suggested a dimensional, developmental psychopathology systems model in which: (1) hippocampal volumetric differences covary with PTSD severity; (2) hippocampal volumetric differences do not become apparent until adulthood; and (3) PTSD is associated with abnormalities in multiple frontal-limbic system structures.

Adult↗
PubMed2006

Structural brain alterations following 5 days of intervention: dynamic aspects of neuroplasticity.

Activation-dependent brain plasticity in humans on a structural level has been demonstrated in adults after 3 months of training a visio-motor skill. The exact timescale of usage-dependent structural changes, whether days, months, or years, is, however, still debated. A better understanding of the temporal parameters may help elucidate to what extent this type of cortical plasticity contributes to fast adapting cortical processes that may be relevant to learning and effects of treatments. Using voxel-based morphometry, we are able to show that repetitive transcranial magnetic stimulation delivered to the superior temporal cortex causes macroscopic cortical changes in gray matter (GM) in the auditory cortex as early as within 5 days of continuous intervention. These structural alterations are mirrored by changes in cortical evoked potentials attributed to the GM changes and demonstrate the rapid dynamics of these processes, which occur within a time range characteristic for the onset of behavioral effects induced by a variety of treatment methods for neuropsychiatric diseases. Our finding suggests that cortical plasticity on a structural level in adult humans is already detectable after 1 week, which provides support for fast adjusting neuronal systems, such as spine and synapse turnover, and contradicts slow evolving mechanisms, such as neuronal or glial cell genesis.

Adult↗
PubMed1981

[Functional status of certain subcortical brain structures during adaptation and deadaptation to physical loading].

Experiments on 35 rabbits were made to study the time course of the function of the dorsal hippocamp, reticular formation of the midbrain, ventromedial hypothalamus, caudate nucleus and anteromedial thalamus in the course of prolonged adaptation to exercise and during deadaptation. It was determined that the most considerable changes in excitability and brain blood circulation were recorded within the first 10 days of exercise. From the 20th day of the experiment, abnormalities in the function of the structures under study, except those in the hypothalamus, got stabilized, which is regarded as adaptive reaction. In the course of adaptation the periodicity of the function of the brain structures was defined.

Adaptation, Physiological↗
PubMed2000

Gender effects on age-related changes in brain structure.

BACKGROUND AND PURPOSE: Previous reports have suggested that brain atrophy is associated with aging and that there are gender differences in brain atrophy with aging. These reports, however, neither exclude silent brain lesions in "healthy subjects" nor divide the brain into subregions. The aim of this study is to clarify the effect of gender on age-related changes in brain subregions by MR imaging. METHODS: A computer-assisted system was used to calculate the brain matter area index (BMAI) of various regions of the brain from MR imaging of 331 subjects without brain lesions. RESULTS: There was significantly more brain atrophy with aging in the posterior parts of the right frontal lobe in male subjects than there was in female subjects. Age-related atrophy in the middle part of the right temporal lobe, the left basal ganglia, the parietal lobe, and the cerebellum also was found in male subjects, but not in female subjects. In the temporal lobe, thalamus, parieto-occipital lobe, and cerebellum, brain volume in the left hemisphere is significantly smaller than in the right hemisphere; sex and age did not affect the hemisphere differences of brain volume in these regions. CONCLUSION: The effect of gender on brain atrophy with aging varied in different subregions of the brain. There was more brain atrophy with aging in male subjects than in female subjects.

Adult↗
PubMedDate not supplied

[Neuron reactions of brain structures suppressing motion during development of animal hypnosis in guinea pigs].

Multisensory and motor units are suppressed in hypnosis in the guinea pig giganto-cellular reticular nucleus and in the dorsolateral. pons. In contrast, inhibitory intexneuvons neurons and the ponto-medulla neurons are activated in hypnosis. The data obtained suggests a key role of the brain-stem structures in descending unspecific inhibition during hypnosis in animals.

Animals↗
PubMed2005

Structural brain imaging of attention-deficit/hyperactivity disorder.

Many investigators have hypothesized that attention-deficit/hyperactivity disorder (ADHD) involves structural and functional brain abnormalities in frontal-striatal circuitry. Although our review suggests that there is substantial support for this hypothesis, a growing literature demonstrates widespread abnormalities affecting other cortical regions and the cerebellum. Because there is only one report studying adults with ADHD, this summary is based on children. A key limitation of the literature is that most of the studies until recently have been underpowered, using samples of fewer than 20 subjects per group. Nevertheless, these studies are largely consistent with the most comprehensive and definitive study (Castellanos et al 2002). Moreover, studies differ in the degree to which they address the influence of medications, comorbidities, or gender, and most have not addressed potentially important sources of heterogeneity such as family history of ADHD, subtype, or perinatal complications. Despite these limitations, a relatively consistent picture has emerged. The most replicated alterations in ADHD in childhood include significantly smaller volumes in the dorsolateral prefrontal cortex, caudate, pallidum, corpus callosum, and cerebellum. These results suggest that the brain is altered in a more widespread manner than has been previously hypothesized. Developmental studies are needed to address the evolution of this brain disorder into adulthood.

Adult↗
PubMedDate not supplied

A histochemical study of the distribution of aldehyde dehydrogenase activity in brain structures of rats with genetically different alcohol-related behaviour.

Brain samples from rats genetically selected for high or low voluntary alcohol intake (AA and ANA strains) or for differences in alcohol-induced motor incoordination (AT and ANT strains) were analyzed by histochemistry for aldehyde dehydrogenase (EC 1.2.1.3; ALDH) activity in various CNS structures. All strains exhibited the highest ALDH activities in neurons of the mesencephalic tract of trigeminal nerve nucleus and in spinal cord motoneurons, while the lowest activities were observed in the somatosensory cortex. Although the general distribution pattern of ALDH activity was similar in the genetically selected strains, some potentially important differences were observed. AA rats with high voluntary alcohol consumption had lower ALDH activity (with acetaldehyde as substrate) in the neuropil of the olfactory tubercle but higher activity (with benzaldehyde as substrate) in the spinal cord motoneurons, Purkinje cells and capillary endothelium of the cerebellum as compared to the corresponding structures from the alcohol avoiding ANA rats. Alcohol-resistant AT rats had higher ALDH activity, with benzaldehyde, in most CNS structures than did the alcohol-sensitive ANT's, significantly so in the lamina II of the somatosensory cortex and the neurons of the lateral hypothalamic area. This relationship was also found with acetaldehyde as substrate in the neurons of the hypothalamic arcuate nuclei and in cerebellar capillaries, but the ANT's had the higher activity in the neurons of the cerebral cortex V lamina. We suggest that some of the differences observed may relate to the differences between the rat strains with respect to voluntary alcohol intake and alcohol-induced motor incoordination.

Alcohol Drinking↗
PubMed2006

Interaction of functionalized superparamagnetic iron oxide nanoparticles with brain structures.

Super Paramagnetic Iron Oxide Nanoparticles (SPIONs) combined with magnetic resonance imaging (MRI) are under clinical evaluation to enhance detection of neurodegenerative diseases. A major improvement would be to link therapeutic drugs to the SPIONs to achieve targeted drug delivery, either at the cell surface or intracellularly, together with active disease detection, without inducing cell reaction. Our objectives were to define the characteristics of SPIONS able to achieve cell-specific interaction with brain-derived structures. Our system consisted in an iron oxide core (9-10 nm diameter) coated either with dextran (Sinerem and Endorem) or various functionalized polyvinyl alcohols (PVAs) (PVA-SPIONs). We investigated the cellular uptake, cytotoxicity, and interaction of these various nanoparticles with brain-derived endothelial cells, microglial cells, and differentiating three-dimensional aggregates. None of the nanoparticles coated with dextran or the various PVAs was cytotoxic or induced the production of the inflammatory mediator NO used as a reporter for cell activation. AminoPVA-SPIONs were taken up by isolated brain-derived endothelial and microglial cells at a much higher level than the other SPIONs, and no inflammatory activation of these cells was observed. AminoPVA-SPIONs did not invade brain cells aggregates lower than the first cell layer and did not induce inflammatory reaction in the aggregates. Fluorescent aminoPVA-SPIONs derivatized with a fluorescent reporter molecule and confocal microscopy demonstrated intracellular uptake by microglial cells. Fluorescent aminoPVA-SPIONs were well tolerated by mice. Therefore, functionalized aminoPVA-SPIONs represent biocompatible potential vector systems for drug delivery to the brain that may be combined with MRI detection of active lesions in neurodegenerative diseases.

Animals↗
PubMed2000

Differential mRNA expression of the two mineralocorticoid receptor splice variants within the human brain: structure analysis of their different DNA binding domains.

In human brain tissue, cortisol action, at basal concentrations, is mediated by the mineralocorticoid receptor (MR). An in-frame insertion of 12 bp in the MR-DNA-binding domain due to alternative splice site usage between exons 3 and 4 results in an MR mRNA splice variant (MR+4) encoding a receptor protein with four additional amino acids compared to the wild-type MR protein. To elucidate the questions of sex, age, and/or tissue dependent differences of the relative amount of the two mRNA subtypes, we examined 131 fresh human brain tissue samples from temporal and frontal lobe or hippocampus. One hundred and twenty samples were obtained from patients with epilepsy and 11 samples from patients with brain tumours. A small but significant difference of the MR+4 mRNA splice variant proportions in cortex (9.5 +/- 0.8%) and subcortical white matter (6.6 +/- 0.7%) of the temporal lobe could be detected, indicating differential MR splice variant expression within these brain areas. Moreover, the splice variant ratios in samples of the temporal lobe cortex collected from patients with epilepsy differed from samples of patients with brain tumours. These data point to an altered expression of the MR splice variants in epilepsy, and strengthen the supposition of a tissue specific alternative splicing of the MR mRNA. The frequent occurrence of the MR+4 transcript raises the question of its functional significance. For this reason, an MR+4 DNA-binding-domain structure model was generated by computer-based homology modelling based on the known glucocorticoid receptor structure. The data obtained revealed no distorting effect of the inserted four amino acids on the adjacent secondary structures, thereby suggesting that both zinc fingers retain their function. The resulting structure of the MR+4 model leads to the supposition that the receptor retains its function. Moreover, databank analysis with respect to this kind of steroid receptor variation and our own sequence data of the closely related progesterone receptor sustained the hypothesis that only corticosteroid receptors were affected by this alternative splicing event.

Adult↗