Agenda and attachments, November 14, 2012

<p>Abbreviations: STG = superior temporal gyrus; mFG = medial frontal gyrus; SMA = supplementary motor area; ITG = inferior temporal gyrus; FG = fusiform gyrus; MTG = middle temporal gyrus; MOG = middle occipital gyrus; PCu = precuneus; R = right side; L = left side; BA = Brodmann’s area; BA = Brodmann’s area; N/A = not applicable.</p><p><b><i>T</i></b>: functional connectivity strength of the left/right thalamus and <i>T</i> value was obtained by a one sample t-test; <b><i>CC</i></b>: correlation coefficient; <b>“↓+":</b> decrease in positive functional connectivity; <b>”↓-“</b>: decrease in negative functional connectivity; <b>”↑+“</b>: increase in positive connectivity; <b>”</b></p><p><b>↑-“</b>: increase in negative connectivity;”</p><p>The last two columns show the correlation coefficient and corresponding <i>p</i> value between the strength of functional connectivity and MMSE scores, and the results for a threshold of <b><i>p</i> < 0.05</b> are shown in bold.</p><p>Regions showing functional connectivity differences of the left/right thalamus between the EMCI and HC group (<i>P</i> < 0.01, 40 voxels, corrected for multiple comparisons).</p

Changes in Thalamic Connectivity in the Early and Late Stages of Amnestic Mild Cognitive Impairment: A Resting-State Functional Magnetic Resonance Study from ADNI

<div><p>We used resting-state functional magnetic resonance imaging (fMRI) to investigate changes in the thalamus functional connectivity in early and late stages of amnestic mild cognitive impairment. Data of 25 late stages of amnestic mild cognitive impairment (LMCI) patients, 30 early stages of amnestic mild cognitive impairment (EMCI) patients and 30 well-matched healthy controls (HC) were analyzed from the Alzheimer’s disease Neuroimaging Initiative (ADNI). We focused on the correlation between low frequency fMRI signal fluctuations in the thalamus and those in all other brain regions. Compared to healthy controls, we found functional connectivity between the left/right thalamus and a set of brain areas was decreased in LMCI and/or EMCI including right fusiform gyrus (FG), left and right superior temporal gyrus, left medial frontal gyrus extending into supplementary motor area, right insula, left middle temporal gyrus (MTG) extending into middle occipital gyrus (MOG). We also observed increased functional connectivity between the left/right thalamus and several regions in LMCI and/or EMCI including left FG, right MOG, left and right precuneus, right MTG and left inferior temporal gyrus. In the direct comparison between the LMCI and EMCI groups, we obtained several brain regions showed thalamus-seeded functional connectivity differences such as the precentral gyrus, hippocampus, FG and MTG. Briefly, these brain regions mentioned above were mainly located in the thalamo-related networks including thalamo-hippocampus, thalamo-temporal, thalamo-visual, and thalamo-default mode network. The decreased functional connectivity of the thalamus might suggest reduced functional integrity of thalamo-related networks and increased functional connectivity indicated that aMCI patients could use additional brain resources to compensate for the loss of cognitive function. Our study provided a new sight to understand the two important states of aMCI and revealed resting-state fMRI is an appropriate method for exploring pathophysiological changes in aMCI.</p></div

Brain regions show significant connectivity to the left/right thalamus in LMCI patients, EMCI patients and healthy age-matched control group (<i>P</i> < 0.01, 40 voxels, Alphasim corrected).

<p>(a) LMCI patients in the left thalamus; (b) LMCI patients in the right thalamus; (c) EMCI patients in the left thalamus; (d) EMCI patients in the right thalamus; (e) HC group in the left thalamus; (f) HC group in the right thalamus.</p

Regions showing functional connectivity differences in the left/right thalamus among the LMCI, EMCI and HC (<i>P</i> < 0.01, 40 voxels, corrected for multiple comparisons).

<p>Abbreviations: ITG = inferior temporal gyrus; MTG = middle temporal gyrus; STG = superior temporal gyrus; MOG = middle occipital gyrus; IFG = inferior frontal gyrus; ACG = anterior cingulate and paracingulate gyrus; SMA = supplementary motor area; mFG = medial frontal gyrus; SPG = superior parietal gyrus; FG = fusiform gyrus; INS = insula; CUN = cuneus; PreCG = precentral gyrus; R = right side; L = left side; BA = Brodmann’s area; N/A: not applicable.</p><p>Regions showing functional connectivity differences in the left/right thalamus among the LMCI, EMCI and HC (<i>P</i> < 0.01, 40 voxels, corrected for multiple comparisons).</p

Brain areas with significant differences in the functional connectivity to the left thalamus (a) and right thalamus (b) among LMCI patients, EMCI patients and healthy control group (<i>P</i> < 0.01, 40 voxels, Alphasim corrected).

<p>Brain areas with significant differences in the functional connectivity to the left thalamus (a) and right thalamus (b) among LMCI patients, EMCI patients and healthy control group (<i>P</i> < 0.01, 40 voxels, Alphasim corrected).</p

Demographics and clinical information.

<p>Data are given as mean ± standard deviation (SD); MMSE, Mini-Mental State Examination; CDR, Clinical Dementia Rating</p><p>a: The <i>P</i> value was obtained by an independence Pearson chi-square test.</p><p>b: The <i>P</i> value was obtained by a one-way analysis of variance test.</p><p>Demographics and clinical information.</p

Left (a) and right (b) thalamus connectivity difference maps between LMCI patients and healthy control group (<i>P</i> < 0.01, 40 voxels, Alphasim corrected).

<p>Left (a) and right (b) thalamus connectivity difference maps between LMCI patients and healthy control group (<i>P</i> < 0.01, 40 voxels, Alphasim corrected).</p

The correlation between framewise displacement (FD) and time series of left/right thalami in the three groups.

<p>The correlation coefficient <i>r</i> is given as mean ± standard deviation (m±SD).</p><p>LMCI_L/R: The correlation between FD and time series of the left/right thalami in LMCI; EMCI_L/R: The correlation between FD and time series of the left/right thalami in EMCI; NC_L/R: The correlation between FD and time series of the left/right thalami in NC;</p><p>c: The <i>P</i> value was obtained by a one sample <i>t</i>-test (confidence interval: 95%), hypothesis: there is no correlation between FD and time series of bilateral thalami.</p><p>The correlation between framewise displacement (FD) and time series of left/right thalami in the three groups.</p

Hyperthermia-Induced Disruption of Functional Connectivity in the Human Brain Network

<div><p>Background</p><p>Passive hyperthermia is a potential risk factor to human cognitive performance and work behavior in many extreme work environments. Previous studies have demonstrated significant effects of passive hyperthermia on human cognitive performance and work behavior. However, there is a lack of a clear understanding of the exact affected brain regions and inter-regional connectivities.</p> <p>Methodology and Principal Findings</p><p>We simulated 1 hour environmental heat exposure to thirty-six participants under two environmental temperature conditions (25°C and 50°C), and collected resting-state functional brain activity. The functional connectivities with a preselected region of interest (ROI) in the posterior cingulate cortex and precuneus (PCC/PCu), furthermore, inter-regional connectivities throughout the entire brain using a prior Anatomical Automatic Labeling (AAL) atlas were calculated. We identified decreased correlations of a set of regions with the PCC/PCu, including the medial orbitofrontal cortex (mOFC) and bilateral medial temporal cortex, as well as increased correlations with the partial orbitofrontal cortex particularly in the bilateral orbital superior frontal gyrus. Compared with the normal control (NC) group, the hyperthermia (HT) group showed 65 disturbed functional connectivities with 50 of them being decreased and 15 of them being increased. While the decreased correlations mainly involved with the mOFC, temporal lobe and occipital lobe, increased correlations were mainly located within the limbic system. In consideration of physiological system changes, we explored the correlations of the number of significantly altered inter-regional connectivities with differential rectal temperatures and weight loss, but failed to obtain significant correlations. More importantly, during the attention network test (ANT) we found that the number of significantly altered functional connectivities was positively correlated with an increase in executive control reaction time.</p> <p>Conclusions/Significance</p><p>We first identified the hyperthermia-induced altered functional connectivity patterns. The changes in the functional connectivity network might be a possible explanation for the cognitive performance and work behavior alteration.</p> </div

Maps of brain regions showing significant positive or negative correlations with the PCC/PCu in a voxel-wise manner of within-group analysis.

<p>(a) NC group, (b) HT group and between-group analysis (c).</p