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PubMed1994

Age dependent white matter lesions and brain volume changes in healthy volunteers.

The brain of 142 healthy volunteers aged 21 to 80 years were investigated using MR imaging. The number and size of the white matter hyperintensity lesions (WMHL) in the cerebral hemispheres were determined. Furthermore, the volume of the cerebral hemispheres and of the lateral ventricles was measured. An almost linear increase in the number of volunteers with WMHL was seen with aging for males and females. With aging a significant decrease in the volume of the cerebral hemispheres was found for males, and a significant increase in the volume of the lateral ventricles was seen for both males and females. Our results suggest that with aging central atrophy increases more (relatively) than cortical atrophy. No correlation was found between the decreasing volume of the cerebral hemispheres and the increasing number and size of WMHL, nor between the increasing volume of the lateral ventricles and the increasing number and size of WMHL.

Adult↗
PubMed2005

Quantitative brain MRI in alcohol dependence: preliminary evidence for effects of concurrent chronic cigarette smoking on regional brain volumes.

BACKGROUND: Recent in vivo research using magnetic resonance spectroscopy demonstrated that chronic cigarette smoking exacerbates regional chronic alcohol-induced brain injury. Other studies associated cigarette smoking with gray matter volume reductions in healthy adults, with greater brain atrophy in aging, and with poorer neurocognition. Although cigarette smoking is common among alcohol-dependent individuals, previous research did not account for the potential effects of chronic smoking on regional brain volumes in alcoholism. METHODS: High-resolution T1-weighted magnetic resonance images from one-week-abstinent, alcohol-dependent individuals and light drinkers were automatically segmented into gray matter, white matter, and cerebral spinal fluid of lobes and subcortical structures. A brief neuropsychological test battery was used to assess cognition in alcohol-dependent individuals. The alcoholic and nondrinking groups were retrospectively divided into chronic smokers and nonsmokers, and the volumetric data were analyzed as a function of alcohol and smoking status. RESULTS: Chronic alcohol dependence was associated with smaller volumes of frontal and parietal white matter, parietal and temporal gray matter, and thalami, accompanied by widespread sulcal but not ventricular enlargements. Chronic cigarette smoking was associated with less parietal and temporal gray matter and with more temporal white matter. Among alcoholics, better visuospatial learning and memory and greater visuomotor scanning speed were correlated with larger lobar white matter volumes in the nonsmoking alcohol-dependent group only. CONCLUSIONS: These data provide preliminary evidence that comorbid chronic cigarette smoking accounts for some of the variance associated with cortical gray matter loss and appears to alter relationships between brain structure and cognitive functions in alcohol-dependent individuals.

Adult↗
PubMed2006

Behavioral flexibility positively correlated with relative brain volume in predatory bats.

We investigated the potential relationships between foraging strategies and relative brain and brain region volumes in predatory (animal-eating) echolocating bats. The species we considered represent the ancestral state for the order and approximately 70% of living bat species. The two dominant foraging strategies used by echolocating predatory bats are substrate-gleaning (taking prey from surfaces) and aerial hawking (taking airborne prey). We used species-specific behavioral, morphological, and ecological data to classify each of 59 predatory species as one of the following: (1) ground gleaning, (2) behaviorally flexible (i.e., known to both glean and hawk prey), (3) clutter tolerant aerial hawking, or (4) open-space aerial hawking. In analyses using both species level data and phylogenetically independent contrasts, relative brain size was larger in behaviorally flexible species. Further, relative neocortex volume was significantly reduced in bats that aerially hawk prey primarily in open spaces. Conversely, our foraging behavior index did not account for variability in hippocampus and inferior colliculus volume and we discuss these results in the context of past research.

Adaptation, Psychological↗
PubMed2000

One-year age changes in MRI brain volumes in older adults.

Longitudinal studies indicate that declines in cognition and memory accelerate after age 70 years. The neuroanatomic and neurophysiologic underpinnings of cognitive change are unclear, as there is little information on longitudinal brain changes. We are conducting a longitudinal neuroimaging study of nondemented older participants in the Baltimore Longitudinal Study of Aging. This report focuses on age and sex differences in brain structure measured by magnetic resonance imaging during the first two annual evaluations. Cross-sectional results from 116 participants aged 59-85 years reveal significantly larger ventricular volumes and smaller gray and white matter volumes in older compared with younger participants and in men compared with women. Regional brain volumes show that the effects of age and sex are not uniform across brain regions. Age differences are greatest for the parietal region. Sex differences tend to be larger for frontal and temporal than parietal and occipital regions. Longitudinal analysis demonstrates an increase of 1526 mm(3) in ventricular volume over 1 year, but no detectable change in total or regional brain volumes. Definition of the pattern and rate of longitudinal brain changes will facilitate the detection of pathological brain changes, which may be predictors of dementia.

Age Factors↗
PubMed2002

Brain volume changes in first-episode schizophrenia: a 1-year follow-up study.

BACKGROUND: Imaging studies of patients with schizophrenia have demonstrated that brain abnormalities are largely confined to decreases in gray matter volume and enlargement of the lateral and third ventricles. Global gray matter volume has been reported to progressively decrease in childhood-onset and chronic schizophrenia. Global gray matter volumes have not been examined longitudinally in patients with first-episode schizophrenia. One would expect global gray matter to decrease progressively, particularly in first-episode patients, because clinical deterioration is greatest in the early stages of the disease. METHODS: Patients with first-episode schizophrenia who had taken antipsychotic medication for 0 to 16 weeks (n = 34) and matched healthy comparison subjects (n = 36) were included in the study. For all subjects, magnetic resonance imaging scans of the whole brain were obtained at inclusion and after 1 year (mean [SD], 12.7 [1.1] months). Outcome was measured 2 years after inclusion. To compare morphological changes over time between patients and healthy comparison subjects, multiple repeated-measures analyses of variance were conducted with intracranial volume as a covariate. Outcome and cumulative antipsychotic medication were related to changes in patients' brain volumes. RESULTS: Total brain volume (-1.2%) and gray matter volume of the cerebrum (-2.9%) significantly decreased and lateral ventricle volume significantly increased (7.7%) in patients. The decrease in global gray matter volume significantly correlated with outcome and, independently of that, with higher cumulative dosage of antipsychotic medication. CONCLUSIONS: The loss of global gray matter in schizophrenia is progressive, occurs at an early stage of the illness, and is related to the disease process and antipsychotic medication.

Adolescent↗
PubMed2006

Hormone replacement therapy, brain volumes and white matter in postmenopausal women aged 60-64 years.

Research on the structural and functional effects of hormone replacement therapy on the brain has produced inconsistent results. This paper reports on cross-sectional associations between hormone replacement therapy use and volumes of brain structures measured using magnetic resonance imaging in 213 postmenopausal women aged 60-64 years recruited from a large population study. Of these, 64 were current hormone replacement therapy users, 69 previous users and 80 had never used hormone replacement therapy. No differences were observed between groups in total grey matter, white matter, hippocampal or amygdalar volumes, severity or volume of white matter hyperintensities, or in different measures of brain atrophy. While acknowledging the limitations of a cross-sectional study, the results argue against hormone replacement therapy being protective against brain changes associated with ageing in women in their early 60s.

Brain↗
PubMed2001

Stereological analysis of regional brain volumes and neuron numbers in rats displaying a spontaneous hydrocephalic condition.

Stereological methods were employed to investigate a novel spontaneously occurring brain mutation in an inbred colony of Wistar rats. These mutants displayed changes (enlarged cerebral ventricles and malformed hippocampi) similar to those seen in H-Tx hydrocephalic rats. Mutant and control rats were studied at three postnatal ages: 4, 7, and 13 weeks. Brain weight in the mutant animals was significantly (P < 0.05) increased when compared to age-matched controls. Using systematic random sampling and the Cavalieri principle we estimated the volumes of various brain compartments, including the cerebral ventricles, forebrain, and cerebral cortex. We found that ventricular volume (P < 0.001) and forebrain volume (P < 0.05) were significantly increased in mutant rats when compared to control rats. Total numbers of nucleoli, estimated using the physical fractionator, were obtained for neurons in the cerebral cortex and granule cells in the dentate gyrus. Numbers were not altered significantly in mutant rats. Nor were mean soma volumes as estimated from total volumes and numbers. The changes in brain and ventricle volumes provide quantitative evidence that these animals display a hydrocephalic condition. This condition appears not to compromise cell number or mean soma size in the brain regions examined.

Aging↗
PubMed1993

Control of brain volume during hyperosmolar and hypoosmolar conditions.

The brain is particularly vulnerable to disturbances of body fluid osmolality. Studies in animals indicate that brain adaptation to osmotic stresses is a very complex process involving transient changes in water content and sustained changes in electrolyte and organic osmolyte contents. Appreciation of the nature of the adaptation process enables a better understanding of the marked variations in neurological sequelae that characterize hyper- and hypoosmolar states and provides a basis for more rational therapy.

Animals↗
PubMed1997

Reduced subcortical brain volumes in nonpsychotic siblings of schizophrenic patients: a pilot magnetic resonance imaging study.

Substantial evidence suggests that nonpsychotic relatives of schizophrenia patients manifest subtle abnormalities in communication, eye movements, event-related potentials, and neuropsychological processes of attention, reasoning, and memory. We sought to determine whether adult relatives without psychosis or schizophrenia spectrum diagnoses might also have structural brain abnormalities, particularly in subcortical regions found to be impaired in patients with schizophrenia itself. Subjects were six sisters of schizophrenic patients and eleven normal female controls. Sixty contiguous 3 mm coronal, T1-weighted 3D magnetic resonance images (MRI) of the entire brain were acquired on a 1.5 Tesla magnet. Cortical and subcortical gray and white matter was segmented using a semiautomated intensity contour mapping algorithm. Volumes were adjusted for total brain volumes. Adjusted gray matter subcortical volumes were significantly smaller in relatives than in controls in total hippocampus, right amygdala, right putamen, left thalamus, and brainstem. Relatives had significantly enlarged left and total inferior lateral ventricles. These results, though preliminary, suggest that some never-psychotic relatives of schizophrenic patients have abnormal brain structure. If replicated in a larger sample including both sexes, these results would suggest that the genetic liability to schizophrenia is also expressed as structural brain abnormalities.

Adolescent↗
PubMed1993

Smaller local brain volumes and cerebral atrophy in spontaneously hypertensive rats.

Spontaneously hypertensive rats (SHR) have enlarged cerebral ventricles from 8 weeks of age onward and smaller brains than age-matched, normotensive Wistar-Kyoto (WKY) rats (controls). At 6-7 months of age local cerebral glucose utilization is apparently lower in many brain areas of SHR relative to WKY rats. These observations led to the hypothesis that there are morphological differences between these two strains of rats in many, if not all, brain areas. This hypothesis was tested in 6-7-month-old SHR and WKY rats by quantitating 1) the volumes of the ventricular system, whole brain, six gray matter structures, and two white matter areas; 2) the thickness of two regions of the cerebral cortex; and 3) the frequency of neuronal nuclei (neuronal frequency) in nine brain areas. Ventricular volume was twofold greater in SHR than in control rats. The volumes of the entire brain and all six gray matter structures plus the thickness of the two cortical regions were 11-25% less in SHR. Neuronal frequency was, however, similar in the two rat strains. The latter finding coupled with the smaller regional tissue volumes indicates appreciably fewer neurons per brain structure in young adult SHR than in controls. These results indicate significant cerebral structural differences between young adult SHR and WKY rats and suggest that structure as well as metabolism are abnormal in the SHR brain.

Animals↗
PubMed2002

Methylprednisolone effect on brain volume and enhancing lesions in MS before and during IFNbeta-1b.

OBJECTIVE: To determine the effect of IV methylprednisolone (IVMP) on brain fraction volume (BFV), contrast-enhancing (CE) lesions, and white matter lesion load (WMLL) in patients with relapsing-remitting MS treated for acute exacerbations. BACKGROUND: MRI metrics of MS disease activity are being used as outcome measures in early phase treatment trials, however the short-term effects of IVMP treatment on cerebral atrophy are unknown. METHODS: Serial monthly MRI were performed in 26 patients enrolled in a baseline vs treatment trial with interferon beta-1b (IFNbeta-1b) who were followed for 3 months before and after IVMP. All 26 patients were evaluated while receiving IFNbeta-1b, and 12 patients were also studied during the baseline stage of the trial (NHx). Acute exacerbations were treated with IVMP (1 g/d) for 3 to 5 days. Precontrast and postcontrast T1-weighted and proton density T2-weighted fast spin-echo images were analyzed. RESULTS: Fifty-six acute exacerbations were evaluated. For the 3 months before IVMP, there was no difference in WMLL or BFV compared to month IVMP was administered. There was a significant decrease in BFV at month 1 after IVMP in the IFNbeta-1b and NHx groups. Compared to the month IVMP was administered, there was a difference in the CE lesions for months -3 and -1 prior (p < 0.039) in NHx patients. Following IVMP, CE lesions decreased (p < 0.0004) for months 1, 2, and 3 in both groups, but there was no effect on WMLL. CONCLUSIONS: BFV and CE lesions were significantly decreased for 1 month (BFV) and 3 months (CE lesions) following IVMP. Therefore, MRI studies should be delayed by probably at least 2 months following IVMP to avoid a possible confounding steroid effect in a clinical trial.

Adjuvants, Immunologic↗
PubMed2002

Brain volumes and surface morphology in monozygotic twins.

Because healthy monozygotic twins share an identical genetic complement, they provide a unique opportunity to explore the genetic and environmental determinants of brain development. The purpose of this study was to evaluate the similarities between measures of cerebral and subcortical volumes and surface morphology in monozygotic twins compared with a matched control sample. Combinations of automated and manual methods were used to evaluate total brain volume, gray matter, white matter, ventricles and volumes of the frontal, temporal, parietal and occipital lobes. An artificial neural network algorithm was used to measure the cerebellum, thalamus, caudate and putamen. Measures of surface morphology included an index of gyral and sulcal curvature, surface area and cortical depth. The cerebral volume regions, including the gray matter, white matter and lobar volumes, were highly correlated within monozygotic twin pairs, with nearly all correlation coefficients >0.90. The cerebellum was also highly correlated (r = 0.99). Reasonably high correlations were found for the cortical depth (r = 0.84), caudate (r = 0.84), thalamus (r = 0.75) and putamen (r = 0.75). The surface measures, however, demonstrated the least correlation within twin pairs and thus are more prone to environmental influences. The high to moderate correlations between MZ twins compared with the matched controls highlights the role of heredity in both prenatal and postnatal neurodevelopment.

Adolescent↗
PubMed2003

Brain volume, asymmetry and intellectual impairment in relation to sex in early-onset schizophrenia.

BACKGROUND: Accumulating evidence suggests that early-onset schizophrenia arises from a disturbance in the normal trajectory of cerebral development. AIMS: To investigate brain structure, asymmetry and IQ in early-onset schizophrenia. METHOD: Volumes of left and right cerebral hemispheres and IQ were assessed in 33 participants with early-onset DSM-IV schizophrenia and 30 members of a matched, normal control group. RESULTS: Total brain volume was significantly smaller in the group with early-onset disease ('cases') relative to the control group (4.5%), especially for the left hemisphere in males (6.0%). A significant sex x diagnosis interaction in hemisphere asymmetry revealed that the female cases group had significantly reduced rightward asymmetry relative to the female control group and that the male cases tended to have reduced leftward asymmetry relative to the male control group. Decreased left hemisphere volume in males and decreased rightward hemispheric asymmetry in females correlated with reduced IQ. CONCLUSIONS: Sexually dimorphic alterations in asymmetry correlate with degree of intellectual impairment in early-onset schizophrenia.

Adolescent↗
PubMed2004

Gray and white matter brain volume in aged rats raised on n-3 fatty acid deficient diets.

Omega-3 or n-3 fatty acids, especially docosahexaenoic acid, are important structural lipids in the brain. Their deficiency leads to a number of sensory, cognitive and behavioral effects. In previous studies, we showed that n-3 deficiency led to a decrease in the neuronal size of a number of brain regions in young rats. In particular, the neuronal size in the hippocampus CA1-CA3 layers decreased with a slight increase in the volumes of these layers. Therefore, we asked whether fatty acid deficiency could affect rat brain morphology in older animals. To address this question, we carried out gross morphological analysis using Magnetic Resonance Imaging on the gray and white matter volumes of brains in older rats (> 15 months) that were raised on n-3 deficient diets for three generations. We did not detect any differences in the total or regional gray and white matter volumes of brains of old rats maintained on a n-3 deficient or supplemented diet.

Aging↗
PubMed2002

The 2-oxopyrrolidinacetamide piracetam reduces infarct brain volume induced by permanent middle cerebral artery occlusion in male rats.

In this study, the temporal development of focal cerebral infarction induced by permanent middle cerebral artery occlusion (pMCAO) and the effects of piracetam, a derivative of gamma-aminobutyric acid widely used in clinical practice as a nootropic agent, on infarct area and volume were investigated. pMCAO caused a cerebral infarct whose size progressively increased after 3, 6, 9, and 24 h. Piracetam (125 mg/kg i.p.), administered 6, 9, and 22 h after pMCAO, did not reduce pMCAO-induced brain infarct area size detected at the 24th hour. By contrast, when this agent was administered at the doses of 250 and 500 mg/kg, it caused a marked reduction of the infarct area size. This reduction was observed in almost every brain slice affected by pMCAO, although statistical differences (p <0.05) were detected in slices located at 3-5.5 mm posterior to the anterior pole in animals treated with 250 mg/kg piracetam and in slices located at 3.5-5 mm in those receiving 500 mg/kg. When the mean total volumes of brain infarct resulting from pMCAO were calculated, it was observed that in animals which had received piracetam (250 or 500 mg/kg) infarction volume was markedly ( approximately 50%) and significantly (p <0.05) reduced in comparison with saline injected rats. Finally, piracetam (250 mg/kg administered i.p. 6, 9, and 22 h after the ischemic insult) significantly reduced brain infarct area evaluated 48 h and 7 days after pMCAO.

Animals↗