Neuroscience
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Being able to inhibit an impending movement in response to a contextual change is a distinctive feature of action control. Such inhibitory control relies on a complex cortical-subcortical network, including posterior prefrontal regions such as caudal inferior frontal gyrus and pre-supplementary motor area. According to hierarchical models of action control, both areas represent the intermediate level between prefronto-dependent and motor-related cortices. ⋯ Effective TMS on SMA-proper produced no effect on STOP trials' performance (p = 0.31) nor in the GO trial performance (p = 0.56). Our data show that there is at least a portion of PMCd playing a distinctive role in the control of mouth-related M1 during instructed visuomotor inhibitory behavior. This region could therefore represent a low-level hierarchical node for externally cued action inhibition.
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Transient receptor potential vanilloid type 4 (TRPV4) channels are involved in astrocyte volume regulation; however, only limited data exist about its mechanism in astrocytes in situ. We performed middle cerebral artery occlusion in adult mice, where we found twice larger edema 1 day after the insult in trpv4-/- mice compared to the controls, which was quantified using magnetic resonance imaging. This result suggests disrupted volume regulation in the brain cells in trpv4-/- mice leading to increased edema formation. ⋯ In contrast to in vitro experiments, we found little evidence of the contribution of TRPV4 channels to volume regulation in astrocytes in situ in adult mice. Moreover, we only found a rare expression of TRPV4 channels in adult mouse astrocytes. Our data suggest that TRPV4 channels are not involved in astrocyte volume regulation in situ; however, they play a protective role during the ischemia-induced brain edema formation.
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Stress during development can shift the typical developmental trajectory. Maternal stress prior to conception has recently been shown to exert similar influences on the offspring. The present study questioned if a consistent maternal stressor prior to conception (elevated platform stress) would impact the pre-weaning development of offspring brain and behavior, and if maternal care was vulnerable to this experience. ⋯ The current study failed to find an effect of maternal preconception stress on early behavioral development. These results suggest that the PFC, and likely behavior dependent on the PFC, is vulnerable to maternal preconception stress and that a strong sex effect is evident. Further studies should examine how such offspring fare using a lifespan model and investigate potential mechanisms responsible for these effects.
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Detecting morphological changes of dendritic spines in time-lapse microscopy images and correlating them with functional properties such as memory and learning, are fundamental and challenging problems in neurobiology research. In this paper, we propose an algorithm for dendritic spine detection in time series. The proposed approach initially performs spine detection at each time point and improves the accuracy by exploiting the information obtained from tracking of individual spines over time. ⋯ Finally, we determine the spine location more precisely by performing a watershed-geodesic active contour model. We quantitatively assess the performance of the proposed spine detection algorithm based on annotations performed by biologists and compare its performance with the results obtained by the noncommercial software NeuronIQ. Experiments show that our approach can accurately detect and quantify spines in 2-photon microscopy time-lapse data and is able to accurately identify spine elimination and formation.