BACKGROUND AND PURPOSE: Decreased oxygen supply may cause neuronal damage in the brains of patients with COPD, which is manifested by clinical symptoms such as neuropsychological deficits and mood disorders. The aim of the present study was to investigate brain gray matter change in COPD. MATERIALS AND METHODS: Using voxel-based morphometry based on the high-resolution 3D T1-weighted MR images of GM volume, we investigated 25 stable patients with COPD and 25 matching healthy volunteers. A battery of neuropsychological tests was also performed. RESULTS: Patients with COPD (versus controls) showed reduced GM volume in the frontal cortex (bilateral gyrus rectus, bilateral orbital and inferior triangular gyri, and left medial superior gyrus), right anterior insula, cingulate cortex (left anterior and middle gyri, right middle gyrus), right thalamus/pulvinar, right caudate, right putamen, right parahippocampus, and left amygdala. In COPD, in some of these regions, regional GM volume had positive correlations with arterial blood po₂, while in some regions, regional GM volume had negative correlations with disease duration. Patients with COPD (versus controls) had poorer performance in the Mini-Mental State Examination, Visual Reproduction, and Figure Memory tests. Moreover, the GM volume in the inferior triangular frontal cortex in patients with COPD was significantly correlated with the Picture Memory score. CONCLUSIONS: Our findings suggest GM reductions in a number of brain regions in COPD, which were associated with disease severity and may underlie the pathophysiologic and psychological changes in patients with COPD.

With the advancement ofin vivomagnetic resonance imaging (MRI) technique, more detailed information about the human brain at high altitude (HA) has been revealed. The present review aimed to draw a conclusion regarding changes in the human brain in both unacclimatized and acclimatized states in a natural HA environment. Using multiple advanced analysis methods that based on MRI as well as electroencephalography, the modulations of brain gray and white matter morphology and the electrophysiological mechanisms underlying processing of cognitive activity have been explored in certain extent. The visual, motor and insular cortices are brain regions seen to be consistently affected in both HA immigrants and natives. Current findings regarding cortical electrophysiological and blood dynamic signals may be related to cardiovascular and respiratory regulations, and may clarify the mechanisms underlying some behaviors at HA. In general, in the past 10 years, researches on the brain at HA have gone beyond cognitive tests. Due to the sample size is not large enough, the current findings in HA brain are not very reliable, and thus much more researches are needed. Moreover, the histological and genetic bases of brain structures at HA are also needed to be elucidated.

Objectives: The irreversible airflow limitation characterised by chronic obstructive pulmonary disease (COPD) causes a decrease in the oxygen supply to the brain. The aim of the present study was to investigate brain structural damage in COPD. Design: Retrospective case–control study. Patients with COPD and healthy volunteers were recruited. The two groups were matched in age, gender and educational background. Setting: A hospital and a number of communities: they are all located in southern Fujian province, China. Participants: 25 stable patients and 25 controls were enrolled from December 2009 to May 2011. Methods: Using voxel-based morphometry and tract-based spatial statistics based on MRI to analyse grey matter (GM) density and white matter fractional anisotropy (FA), respectively, and a battery of neuropsychological tests were performed. Results: Patients with COPD (vs controls) showed decreased GM density in the limbic and paralimbic structures, including right gyrus rectus, left precentral gyrus, bilateral anterior and middle cingulate gyri, bilateral superior temporal gyri, bilateral anterior insula extending to Rolandic operculum, bilateral thalamus/pulvinars and left caudate nucleus. Patients with COPD (vs controls) had decreased FA values in the bilateral superior corona radiata, bilateral superior and inferior longitudinal fasciculus, bilateral optic radiation, bilateral lingual gyri, left parahippocampal gyrus and fornix. Lower FA values in these regions were associated with increased radial diffusivity and no changes of longitudinal diffusivity. Patients with COPD had poor performances in the Mini-Mental State Examination, figure memory and visual reproduction. GM density in some decreased regions in COPD had positive correlations with arterial blood Po ₂ , negative correlations with disease duration and also positive correlations with visual tasks. Conclusion: The authors demonstrated that COPD exhibited loss of regional GM accompanied by impairment of white matter microstructural integrity, which was associated with disease severity and may underlie the pathophysiological and psychological changes of COPD.

The aim of this study was to investigate brain structural alterations in adult immigrants who adapted to high altitude (HA). Voxel-based morphometry analysis of gray matter (GM) volumes, surface-based analysis of cortical thickness, and Tract-Based Spatial Statistics analysis of white matter fractional anisotropy (FA) based on MRI images were conducted on 16 adults (20–22 years) who immigrated to the Qinghai-Tibet Plateau (2300–4400 m) for 2 years. They had no chronic mountain sickness. Control group consisted of 16 matched sea level subjects. A battery of neuropsychological tests was also conducted. HA immigrants showed significantly decreased GM volumes in the right postcentral gyrus and right superior frontal gyrus, and increased GM volumes in the right middle frontal gyrus, right parahippocampal gyrus, right inferior and middle temporal gyri, bilateral inferior ventral pons, and right cerebellum crus1. While there was some divergence in the left hemisphere, surface-based patterns of GM changes in the right hemisphere resembled those seen for VBM analysis. FA changes were observed in multiple WM tracts. HA immigrants showed significant impairment in pulmonary function, increase in reaction time, and deficit in mental rotation. Parahippocampal and middle frontal GM volumes correlated with vital capacity. Superior frontal GM volume correlated with mental rotation and postcentral GM correlated with reaction time. Paracentral lobule and frontal FA correlated with mental rotation reaction time. There might be structural modifications occurred in the adult immigrants during adaptation to HA. The changes in GM may be related to impaired respiratory function and psychological deficits.

Background: Structural and functional networks can be reorganized to adjust to environmental pressures and physiologic changes in the adult brain, but such processes remain unclear in prolonged adaptation to high‐altitude (HA) hypoxia. This study aimed to characterize the interhemispheric functionally and structurally coupled modifications in the brains of adult HA immigrants.Methods: We performed resting‐state functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) in 16 adults who had immigrated to the Qinghai‐Tibet Plateau (2300–4400 m) for 2 years and in 16 age‐matched sea‐level (SL) controls. A recently validated approach of voxel‐mirrored homotopic connectivity (VMHC) was employed to examine the interhemispheric resting‐state functional connectivity. Areas showing changed VMHC in HA immigrants were selected as regions of interest for follow‐up DTI tractography analysis. The fiber parameters of fractional anisotropy and fiber length were obtained. Cognitive and physiological assessments were made and correlated with the resulting image metrics.Results: Compared with SL controls, VMHC in the bilateral visual cortex was significantly increased in HA immigrants. The mean VMHC value extracted within the visual cortex was positively correlated with hemoglobin concentration. Moreover, the path length of the commissural fibers connecting homotopic visual areas was increased in HA immigrants, covarying positively with VMHC.Conclusions: These observations are the first to demonstrate interhemispheric functional and structural connectivity resilience in the adult brain after prolonged HA acclimatization independent of inherited and developmental effects, and the coupled modifications in the bilateral visual cortex indicate important neural compensatory mechanisms underlying visual dysfunction in physiologically well‐acclimatized HA immigrants. The study of human central adaptation to extreme environments promotes the understanding of our brain's capacity for survival.