Resting-state functional connectivity-based parcellation of the human dentate nucleus: new findings and clinical relevance.

For years, the cerebellum was left out of functional magnetic resonance imaging (fMRI) studies due to technological limitations. The advent of novel data acquisition and reconstruction strategies (e.g., whole-brain simultaneous multi-slice imaging) employing multi-channel array coils has overcome such limitations, ushering unprecedented improvements in temporal signal-to-noise ratio and spatiotemporal resolution. Here, we aim to provide a brief report on the deep cerebellar nuclei, specifically focusing on the dentate nuclei, the primary output nuclei, situated within both cognitive and motor cerebello-cerebral circuits. We highlight the importance of functional parcellation in refining our understanding of broad resting-state functional connectivity (RSFC) in both health and disease. First, we review work relevant to the functional topography of the dentate nuclei, including recent advances in functional parcellation. Next, we review RSFC studies using the dentate nuclei as seed regions of interest in neurological and psychiatric populations and discuss the potential benefits of applying functionally defined subdivisions. Finally, we discuss recent technological advances and underscore ultrahigh-field neuroimaging as a tool to potentiate functionally parcellated RSFC analyses in clinical populations.

Examination of the temporal-spatial dynamics of working memory training-induced neuroplasticity.

Efficient working memory (WM) performance involves the dynamic coordination of neural activity on a millisecond time-scale. However, the correspondence between the timing and spatial localization of changes in neural activity following targeted WM training has not been well-established. To address this, we used an event-related potential (ERP) source localization approach to identify the patterns of cortical activity changes that are induced by WM training along both the temporal and spatial dimensions. Healthy adult participants completed approximately 20 sessions of training on either a WM training protocol (visual-letter n-back task), or a control training protocol (visual-letter search task). ERP measures were obtained before and after training (pretest and posttest) for a letter 3-back task. A beamformer source localization method was applied to the ERP data in the N2 (approximately 200-350 msec post-stimulus) and P3 (approximately 300-600 msec post-stimulus) component time windows to identify the cortical activity associated with WM training at distinct stages of information processing. Pretest-to-posttest cortical activity changes that corresponded with WM training gains were observed within the N2 time window, but not the P3 time window. Within the WM training group, training-related enhancement of N2 source activity in bilateral medial orbitofrontal cortex, left rostral anterior cingulate, and right posterior cingulate cortex was significantly associated with behavioral performance improvements on the trained task and untrained tasks of WM. The findings suggest that medial orbitofrontal and cingulate enhancement within 200-350 msec after stimulus onset represents a target for WM training and an important inflection point along the spatial-temporal dimensions of cortical activity for the enhancement of WM performance.

HIV risk perception among pregnant women in western India: need for reducing vulnerabilities rather than improving knowledge!

Since the beginning of the HIV/AIDS epidemic in India, pregnant women attending antenatal clinics (ANC) have been considered as a low HIV risk population. Yet, a substantial proportion of new HIV infections are occurring among stable heterosexual couples. This paper sought to investigate the proportion and profile of women who, within the low-risk population, are potentially at higher risk of HIV infection. HIV risk perception of pregnant women enrolled within the ANRS 12127 Prenahtest trial was described and associated socio-behavioral characteristics, husband's characteristics, and HIV-related characteristics were analyzed using univariate and multivariate logistic regression models. Among 484 women enrolled, baseline data were collected for 479 women and 460 women with completed data were considered for the present analysis (96%). Eighty-nine (19.4%) women perceived themselves at risk of HIV. Women with educational level <11years (Adjusted Odds Ratio, AOR = 2.4 [CI = 1.28-4.53]), who stayed in joint families (AOR = 1.89 [CI = 1.12-3.12]), who had experienced insult or hurt from the partner (AOR = 1.91 [CI = 1.11-3.27]) and whose partner were alcoholic (AOR = 2.19 [CI = 1.31-3.66]) were significantly more likely to perceive themselves at risk of HIV. Women who had heard about sexually transmitted infections were also more likely to report HIV risk perception (AOR = 3.36 [CI = 1.83-6.18]). Substantial proportion of women (one out of five) perceived themselves at risk of HIV and most of these have reported some form of vulnerability in their couple relationship such as intimate partner violence, alcoholic partner, lack of communication, and spaces for communication with partner. Though awareness and knowledge is the first step for prevention, considering the vulnerabilities associated with HIV risk perception, HIV prevention interventions in India should target overall sources of vulnerability to HIV. Targeted risk reduction for women in ANC should be considered for primary HIV prevention among couples.