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The organization of top-down inputs in primary visual cortex (V1) remains unclear. Here the authors characterized corticocortical and thalamocortical top-down inputs recruiting V1 neurons with cell-type and layer-specificities, and revealed distinct forms of top-down input processing.
The neural mechanisms setting the lower limit of conscious visual perception in humans is not fully understood. Here the authors show by correlating human vision experiments and non-human primate retina recordings that primates rely on the retinal ON pathway in perception of the dimmest light increments, and that nonlinear thresholding in this pathway eliminates single photons and neural noise thereby allowing perception of minute differences in light intensity.
How the brain tracks blood glucose dynamics is unclear. Viskaitis et al. show that hypothalamic orexin/hypocretin cells track glucose concentration and rate of change and that their activity is important for glucose-evoked locomotor suppression.
Innate fear-like responses are thought to involve the amygdala, but here a tetra-synaptic pathway is identified that mediates odour-evoked innate fear in mice.