Differences in visual attention and task interference between males and females reflect differences in brain laterality

Two cognitive tasks (a letter memory task and a spatial memory task) designed to selectively activate the left or right hemisphere were combined with attentional probe tasks to measure how hemispheric activation affects attention to left and right hemifields. The probe task in Experiment 1 required the identification of digits in the left and right hemifield. During the letter task, male subjects identified more probes from the left hemifield than from the right. Their accuracy varied little across the two hemifields during the dots task.Experiment 2 tested whether this pattern is due to either spatial attention or interference in character processing. Instead of identifying digits, the probe task required subjects to respond to a black square that appeared in the periphery of the screen. For male subjects, the pattern was opposite of that from Experiment 1. During the letter task they responded faster to the probe in the right hemifield than in the left. Their response times were equivalent across the two hemifields during the dots task.These results indicate two separate effects of laterality in male subjects. The activation of one hemisphere produced more attention to the contralateral hemifield in Experiment 2, and the letter memory task interfered with the processing of other characters in the right visual field more than those in the left visual field in Experiment 1. Neither of these effects appeared in female subjects, corroborating earlier claims that female brains are less lateralized than male brains.     

Sleep quality of benzodiazepine users in nursing homes: A comparative study with nonusers

ObjectivesWe aim to describe subjective sleep quality among long-term users of benzodiazepines (BZDs) in Belgian nursing homes, to compare it to nonusers, and to investigate determinants of poor sleep quality.MethodsAll mentally competent residents from 10 nursing homes were screened and compiled in a group of long-term BZD users or in a group of nonusers based on the medication chart. We collected demographic, functional, and medication characteristics and global and specific sleep parameters using the Pittsburgh Sleep Quality Index (PSQI). Linear regression was used to investigate which parameters were associated with sleep quality.ResultsOf the 300 residents, 178 (59%) were long-term BZD users and 122 were nonusers. The 2 groups did not differ in demographic and functional characteristics (mean age, 85.5 y; range, 57–100; 75% women). The users reported significantly more difficulties with falling asleep, had more midnight awakenings, felt less rested in the morning, and had a poorer self-perceived sleep quality compared to nonusers. Sleep duration and time to fall asleep did not differ. The self-perceived sleep quality was mainly determined by difficulties during initiation of sleep. After controlling for demographic, medication, and functional characteristics, BZD use remained strongly associated with poor sleep (r = 0.173; P = .003), and a study centre effect (differences among nursing homes) was observed (r = 0.229; P < .001).ConclusionOur findings do not support long-term effectiveness of BZDs; long-term users slept more poorly than nonusers and were even more outspoken in users of long-acting BZDs. In future longitudinal comparative studies of sleep quality, unexplained variability needs further assessment with medical, psychologic, and institutional parameters.     

Differences in functional and structural social support among female and male veterans and civilians

Purpose

Social support is an important correlate of health behaviors and outcomes. Studies suggest that veterans have lower social support than civilians, but interpretation is hindered by methodological limitations. Furthermore, little is known about how sex influences veteran–civilian differences. Therefore, we examined veteran–civilian differences in several dimensions of social support and whether differences varied by sex.

Methods

We performed a cross-sectional analysis of the 2012–2013 National Epidemiologic Survey of Alcohol and Related Conditions-III, a nationally representative sample of 34,331 respondents (male veterans = 2569; female veterans = 356). We examined veteran–civilian differences in functional and structural social support using linear regression and variation by sex with interactions. We adjusted for socio-demographics, childhood experiences, and physical and mental health.

Results

Compared to civilians, veterans had lower social network diversity scores (difference [diff] = − 0.13, 95% confidence interval [CI] − 0.23, − 0.03). Among women but not men, veterans had smaller social network size (diff = − 2.27, 95% CI − 3.81, − 0.73) than civilians, attributable to differences in religious groups, volunteers, and coworkers. Among men, veterans had lower social network diversity scores than civilians (diff = − 0.13, 95% CI − 0.23, − 0.03); while among women, the difference was similar but did not reach statistical significance (diff = − 0.13, 95% CI − 0.23, 0.09). There was limited evidence of functional social support differences.

Conclusion

After accounting for factors that influence military entry and social support, veterans reported significantly lower structural social support, which may be attributable to reintegration challenges and geographic mobility. Findings suggest that veterans could benefit from programs to enhance structural social support and improve health outcomes, with female veterans potentially in greatest need.

     

吸烟与健康人脑和脑室容积的改变

Previous studies have reported decreased cerebral volume as a result of smoking.However,little is known about accompanying changes in ventricular volume for healthy subjects who smoke,although ventricular volume is increased in patients with multiple sclerosis who smoke.The present study analyzed whether cerebral volume decreased with smoking through the use of magnetic resonance imaging.In addition,accompanying changes in ventricular volume that resulted from decreased cerebral volume and smoking were analyzed in healthy subjects.When multivariate analysis of covariance was performed by integrating the 2 age groups,aged 20-28 years and 40-49 years,with statistical significance,results showed that cerebral volume of smokers was smaller and ventricular volume was greater compared with the non-smokers.These findings suggest that ventricular volume changes could be utilized to characterize the effects of smoking.     

Decreased thalamic volumes in adolescent inhalant users from Korea and Australia

Objectives. Research investigating the impact of inhalant misuse on brain structure suggests abnormalities in subcortical regions. We investigated the association between inhalant misuse and subcortical brain volumes in adolescents. Methods. Based on a collaborative dataset from South Korea (inhalant users: N = 15, mean age = 16.7, SD = 1.1; controls: N = 15, mean age = 15.4, SD = 1.2) and Australia (inhalant users: N = 7, mean age = 18.2, SD = 1.4; controls: N = 7, mean age = 18.9, SD = 2.6), the volumes of caudate nucleus, putamen, pallidum, amygdala, hippocampus, and thalamus were estimated in adolescent inhalant users and healthy adolescents using FreeSurfer. Results. The results revealed a significantly decreased right thalamic volume in adolescent inhalant users (P = 0.042), along with a trend-level decrease in left thalamic volume (P = 0.061). A negative correlation (r = –0.544; P = 0.036) between thalamic volume and severity of inhalant use (i.e., reduced volumes associated with greater use) was identified among Korean participants. Conclusions. These findings suggest that compared with other subcortical structures, the thalamus is particularly sensitive to damage following chronic inhalant exposure during adolescence.     

Insight and regional brain volumes in schizophrenia

We have investigated the relationship between insight impairment and regional brain volumes (gray and white matter) in schizophrenia using voxel-based morphometry (VBM). Fifty patients with schizophrenia were evaluated using the Scale for Unawareness of Mental Disorders. Magnetic resonance images were acquired, segmented and spatially normalized using optimized VBM routines. No significant inverse correlations were detected between insight impairment and gray or white matter volumes in the prefrontal region (where significant findings had been predicted a priori), or in any other brain areas. Our results do not support previous hypotheses suggesting a relationship between frontal lobe atrophy and impaired insight in patients with schizophrenia.     

Patterns of cranial, brain and sulcal CSF volumes in male and female deficit and nondeficit patients with schizophrenia

Recent evidence suggests that schizophrenia reflects a neurodegenerative process. The studies have not compared brain change patterns in male and female patients with schizophrenia or examined the relation of these patterns to patient subgroups defined by specific symptom domains. Maximum Total Brain Volume (TBVmax), total cranial (TCV), total brain (TBV), sulcal CSF (sCSF), and ventricular (VV) volumes were measured in 66 normal controls (32 females, 34 males), and 85 patients with schizophrenia (21 females, 64 males). Sixty-six patients were categorized as nondeficit and 19 as deficit patients. Patients had smaller TBV and larger VV than normal controls. Patients also showed significant excessive brain volume loss after, but not before, TBVmax was achieved compared with normal controls. Although male patients had larger brain volume loss compared with male normal controls than female patients had compared with female normal controls, there were no significant gender x diagnosis interactions. Male patients with the deficit syndrome, but not those without the deficit syndrome, had significantly larger ventricles than normal controls. There were no other significant deficit/nondeficit differences. The present study suggests that brain volume loss in schizophrenia occurs after TBVmax and that male and female patients and deficit and nondeficit patients with schizophrenia do not demonstrate any differences in the time course of their brain volume reductions.     

Language and brain volumes in children with epilepsy

In this study the relationship between language skill and frontotemporal volumes was compared in 69 medically treated subjects with epilepsy and 34 healthy children, aged 6.1–16.6 years. Also, whether patients with linguistic deficits had abnormal volumes and atypical associations between volumes and language skills in these brain regions was determined. The children underwent language testing and MRI scans at 1.5 T. Brain tissue was segmented and frontotemporal volumes were computed. Higher mean language scores were significantly associated with larger inferior frontal gyrus, temporal lobe, and posterior superior temporal gyrus gray matter volumes in the epilepsy group and in the children with epilepsy with average language scores. Increased total brain and dorsolateral prefrontal gray and white matter volumes, however, were associated with higher language scores in the healthy controls. Within the epilepsy group, linguistic deficits were related to smaller anterior superior temporal gyrus gray matter volumes and there was a negative association between language scores and dorsolateral prefrontal gray matter volumes. These findings demonstrate abnormal development of language-related brain regions, and imply differential reorganization of brain regions subserving language in children with epilepsy with normal linguistic skills and in those with impaired language.     

Regional brain and ventricular volumes in Tourette syndrome

BACKGROUND: The pathophysiology of Tourette syndrome (TS) is thought to involve disturbances in cortico-striato-thalamo-cortical circuitry. The morphological characteristics of the cortical and associated white matter portions of these circuits have not been previously examined in TS subjects. METHODS: High-resolution anatomical magnetic resonance images were acquired in 155 TS and 131 healthy children and adults. The cerebrums and ventricles were isolated and then parcellated into subregions using standard anatomical landmarks. RESULTS: For analyses that included both children and adults, TS subjects were found to have larger volumes in dorsal prefrontal regions, larger volumes in parieto-occipital regions, and smaller inferior occipital volumes. Significant inverse associations of cerebral volumes with age were seen in TS subjects that were not seen in healthy controls. Sex differences in the parieto-occipital regions of healthy subjects were diminished in the TS group. The age-related findings were most prominent in TS children, whereas the diminished sex differences were most prominent in TS adults. Group differences in regional ventricular volumes were less prominent than in the cerebrum. Regional cerebral volumes were significantly associated with the severity of tic symptoms in orbitofrontal, midtemporal, and parieto-occipital regions. CONCLUSIONS: Broadly distributed cortical systems are involved in the pathophysiology of TS. Developmental processes, sexual dimorphisms, and compensatory responses in these cortical regions may help to modulate the course and severity of tic symptoms.     

The other side of estrogen replacement therapy: Outcome study results of mood improvement in estrogen users and nonusers

The effect of estrogen on the brain and body of women is a controversial topic that has received a tremendous amount of attention in the past few years. Recent reviews have focused on hormone replacement therapy (HRT), medical risks, and effects on brain metabolism, cognition, risk of Alzheimer’s disease, and mood. This article summarizes HRT and mood improvement in postmenopausal women. For nondepressed women, experimental designs provide no clear evidence for mood improvement associated with HRT, whereas observational studies are more likely to report mood improvement. There appears to be moderate evidence that HRT facilitates the improvement of clinical depression and the efficacy of antidepressants. Heterogeneity among studies makes it difficult to generalize and recommend HRT for mood improvement in postmenopausal women, but there is a clear need to examine the necessary duration of HRT for neuroprotection to decrease a woman’s risk for depression, cognitive dysfunction, and development of Alzheimer’s disease.     

Meta-analysis of regional brain volumes in schizophrenia

OBJECTIVE: The authors' goal was to determine whether patients with schizophrenia differ from comparison subjects in regional brain volumes and whether these differences are similar in male and female subjects. METHOD: They conducted a systematic search for structural magnetic resonance imaging (MRI) studies of patients with schizophrenia that reported volume measurements of selected cortical, subcortical, and ventricular regions in relation to comparison groups. They carried out a meta-analysis of the volumes of these regions in the patients with schizophrenia and the comparison subjects using a random effects model; they also used random effects regression analysis to examine the influence of gender on effect sizes. RESULTS: Fifty-eight studies were identified as suitable for analysis; these studies included 1,588 independent patients with schizophrenia. Assuming a volume of 100% in the comparison group, they found that the mean cerebral volume of the subjects with schizophrenia was smaller (98%), but the mean total ventricular volume of the subjects with schizophrenia was greater (126%). Relative to the cerebral volume differences, the regional volumes of the subjects with schizophrenia were 94% in the left and right amygdala, 94% in the left and 95% in the right hippocampus/amygdala, and 93% in the left and 95% in the right parahippocampus. Relative to the global ventricular system differences, the largest differences in ventricular subdivisions were in the right and left body of the lateral ventricle, where the volumes of schizophrenic subjects were 116% and 116%, respectively. For most regions, effect size was not significantly related to gender. CONCLUSIONS: Regional structural differences in patients with schizophrenia include bilaterally reduced volume of medial temporal lobe structures. There is a need for greater integration of results from structural MRI studies to avoid redundant research activity.     

Automated ROI-based brain parcellation analysis of frontal and temporal brain volumes in schizophrenia

Structural MRI studies of schizophrenia have yielded a diversity of findings. To help characterize regional gray matter changes in schizophrenia, we used an automated region of interest (ROI)-based approach that targeted frontal and temporal regions in schizophrenia patients. The sample compromised 43 schizophrenia patients (21 chronic patients, 22 unmedicated first episode patients), 20 first episode non-schizophrenia psychosis patients and 47 comparison subjects. Automated regional volume measurement was performed in 22 ROIs, including frontal and temporal cortical subregions and hippocampus. Correlations between volume measures, duration of illness and clinical scores were evaluated. Chronic schizophrenia patients showed gray matter volume differences in left dorsolateral prefrontal cortex (DLPFC) and right supplementary motor area (SMA). First episode psychosis patients presented smaller right anterior cingulate cortex (ACC) and left DLPFC than comparison subjects. Disorganization scores and duration of illness correlated negatively with gray matter volume of DLPFC and SMA in chronic schizophrenia patients. Using an automated ROI-based method, we found volume reductions in lateral and medial frontal regions in both first episode and chronic schizophrenia. The automated ROI-based method can be used as a valid and efficient tool for quantification of regional gray matter volume in schizophrenia in multiple ROIs across the brains of large numbers of subjects.     

Mood state and brain electric activity in ecstasy users

Resting EEG during open and closed eyes and subsequent mood ratings were obtained from 15 Ecstasy users and 14 Ecstasy-naive controls. Absolute spectral power on the scalp, and the three-dimensional, intracerebral distribution of neuroelectric activity using low resolution brain electromagnetic tomography (LORETA) were computed. LORETA revealed global increases of theta, alpha 1 and beta 2/3 power during eyes open in Ecstasy users, and spectral analyses revealed a right-posterior increase of alpha 2 power (confirmed by LORETA) and increased beta band activity during open eyes. Ecstasy users had higher levels of state depressiveness, emotional excitability and a trend-level increase in state anxiety. The observed differences may be related to regular exposure to Ecstasy or other illicit drugs, or may be pre-existing.     

Correlations between regional brain volumes and memory performance in anoxia

This study was aimed at investigating the quantitative relationship between regional brain volumes (hippocampus, amygdala, as well as cerebrum, frontal lobe, parietal lobe, temporal lobe) and performance on anterograde and retrograde memory tests in anoxic patients. We used high-resolution MRI to measure brain volumes in 13 anoxic patients. Neuropsychological testing was conducted contemporaneously with MRI. To control for age and sex, neuroanatomical volume residuals were calculated using regression equations derived from a group of 87 healthy comparison participants. We found that anoxic patients with severe amnesia had hippocampal volumes that were 36% smaller than normal, whereas patients with mild or no amnesia had normal hippocampal volumes. Regional gray matter volumes in severe amnesic anoxics were substantially smaller than expected. Performances on anterograde memory tests were significantly correlated with hippocampal and regional gray matter volume residuals. There was a significant correlation between white matter volume (but not hippocampal volume) and performance on the Visual Retention Test, a multi-dimensional test of cognitive function. There were no significant correlations between neuroanatomical measures and performance on a retrograde memory test. Our results indicate a strong quantitative relationship between performance on anterograde memory tests and hippocampal and regional gray matter volume residuals. Correlations between white matter volume residuals and performance on the VRT were found to be independent of hippocampal volume. Given the strong correlation between hippocampal volume and total gray matter volume residuals, a quantitative, normalized measure of total gray matter volume may provide a good indication of clinical outcome in anoxia.