Updated April 13, 2021
Research Spotlight
Increased Functional Coupling between VTA and Hippocampus during Rest in First-Episode Psychosis
Psychosis is associated with both alterations in the ventral tegmental area—a brain region important for motivation—and the hippocampus—a brain region important for memory. Animal models show that interactions across these regions contributes to risk for and propagation of psychotic symptoms. Gregory et al. use a clinical neuroimaging approach to show enhanced coupling between the ventral tegmental area and hippocampus in individuals within their first episode of psychosis, and further that greater functional coupling was associated with greater symptoms within this group. These findings provide a model about how interactions across regions supporting motivation and memory may contribute to symptoms of psychosis.
Inhibition Underlies Fast Undulatory Locomotion in Caenorhabditis elegans
For an animal to move, its nervous system has to produce alternating contraction of muscles. In undulating nematodes, the neural circuit that underlies locomotion is compact, fully identified, and composed of excitatory and inhibitory motoneurons. The motoneurons in this circuit are analogous to spinal interneurons as their interaction generates the motor pattern while integrating descending and sensory inputs. This allows to ask fundamental questions about the role of inhibition in motor control. Deng et al. find that inhibition is necessary for rapid alternation of antagonistic muscle during fast locomotion in both directions; and that inhibitory-reset, cross-inhibition and disinhibition are likely network mechanisms.
Real-time closed-loop feedback in behavioral time scales using DeepLabCut
Imagine delivering a reward or an optogenetic stimulus when a mouse is just beginning to move a limb, is just changing its posture, or has just begun to move a whisker. Sehara et al. have developed methods for doing just that, i.e for flexibly tracking movement in real-time. Here the authors show that it is possible to use deep neural networks to track the position of multiple whiskers in real time. They also characterize the principal bottlenecks that slow down data acquisition.
Using Cortical Neuron Markers to Target Cells in the Dorsal Cochlear Nucleus
To treat complex pathological phenomena such as tinnitus, it is necessary to explore novel ways to correct abnormal nerve cell activity. Malfatti et al. test how to control an area associated with tinnitus generation (the dorsal cochlear nucleus, DCN) using cortical genetic markers. The authors used light to modulate response to sound of subtypes of cells in normal and transgenic mice, and found unexpected response suppression, response delay, disinhibition and a novel direct modulation of the DCN via the ventral cochlear nucleus. These findings contribute to a framework for controlling the DCN in animal models where the aim is to ameliorate tinnitus.
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