Updated Febuary 13, 2020
Research Spotlight
Network studies of the postnatal hippocampus rarely consider the presence of Cajal-Retzius cells. As a consequence, misclassification of these neurons may result in interpretative errors of mechanistic studies based on cell type-specificity. Here, the authors have proposed a simple set of criteria that can be implemented in anatomical, immunohistochemical and physiological experiments, with the aim of avoiding ambiguous interpretations of experimental results.
Saito & Sugimura investigated the mechanisms of excitatory network activation in the brainstem centers for gaze holding. The authors revealed that excitatory networks were activated via different synaptic mechanisms between horizontal and vertical gaze holding centers.
While critical for survival, it remains unclear how mammals perform odor-based navigation. Gumaste et al. used a “Standard Odor Landscape” to generate well-defined odor plumes of varying degrees of turbulence and tasked mice to use their sense of smell to navigate directly to 1 of the 3 release points. Mice performed this task accurately and rapidly, with no evidence of casting. In comparison, a robot and analogous computational models, using biologically plausible minimal odor based search algorithms performed well, but lacked the robustness of mice to different levels of plume turbulence. Mammalian odor navigation is hence likely based on rather complex neuro-behavioral algorithms.
Also of Interest
Quantifying spatial patterns of region-to-region functional connectivity provides an avenue for testing theories of corticocortical information transformation and organization. This work demonstrates that this quantification is feasible not only in early visual cortex, but even in highly multimodal regions where spatial topography is less clear. Overall, we show that topographic relationships as a common motif functional connectivity across the cortex between regions within the same functional network and that analyzing the lateral prefrontal cortex in terms of topographic connectivity reveals organizational features that voxelwise connectivity analysis misses.
Astrocytes are a critical component of the neural network in the suprachiasmatic nucleus (SCN) required for the generation of precise circadian rhythms. We hypothesized that postsynaptic SCN neurons recruit astrocytes via endocannabinoid signaling to modulate presynaptic GABA release. We demonstrate, using a combination of approaches including whole-cell patch-clamp electrophysiology, GCaMP6 calcium imaging in astrocytes, pharmacology, and manipulation of intracellular signaling cascades using DREADD technology, that SCN neurons release cannabinoids that activate astrocyte intracellular Ca2+ signaling pathways to modulate GABA neurotransmission via adenosine. In addition to unraveling this novel signaling cascade in the SCN, we demonstrate that both CB1 receptor activation and adenosine phase advance the molecular circadian clock, suggesting an important role for astrocytes in modulating clock timing.
Corrective responses mediated by feedback have been shown to adapt according to task demands. They also reflect updates in the recalibration of the motor system to sustained and predictable changes in the environment. The extent of cortical involvement in this process is unknown. Here we demonstrate that cortical lesions from stroke alter the execution of motor patterns, but not their recalibration. This is important since it suggests that stroke survivors retain the potential to correct movements through error-based protocols, which is an ability that could be exploited for rehabilitation purposes.
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