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Hernandez, J.

Publications and source records attributed to Hernandez, J..

2 recordsLinked to original sources

A cognitive representation in primary visual cortex modulated by vision

Primary visual cortex (V1) is a critical substrate for mammalian vision. Traditionally, visual inputs are thought to be the main drivers of V1 activity, with internal signals playing a modulatory role. Here we show that this relationship is inverted for a large fraction of V1 neurons. In rats completing a navigation task in darkness, these neurons encoded progress along physically distinct paths with a shared turn structure. Under illumination, visual stimuli gain-modulated this path-invariant activity rather than replacing it with stimulus-driven responses. Path-invariant V1 neurons were also preferentially coordinated with hippocampal ensembles during sharp-wave ripples, linking them to a brain-wide network involved in learning. These findings establish that an internal model of the world can serve as a primary driver of activity in sensory cortex.

neuroscience

Integrin beta1 optimizes diabetogenic T cell migration and function in the pancreas

T cell search behavior is dictated by their need to encounter their specific antigen to eliminate target cells. However, mechanisms controlling effector T cell motility are highly tissue-dependent. Specifically, how diabetogenic T cells encounter their target beta cells in dispersed islets throughout the pancreas during autoimmune diabetes remains unclear. Using intra-vital 2-photon microscopy in a mouse model of diabetes, we found that CXCR3 chemokine downregulated CD8+ T cell motility specifically within islets, promoting effector cell confinement to their target sites. In contrast, T cell velocity and directionality in the exocrine tissue were enhanced along blood vessels and extra-cellular matrix fibers. This guided migration implicated integrin-dependent interactions, since integrin blockade impaired exocrine T cell motility. In addition, integrin {beta}1 blockade decreased CD4+ T cell effector phenotype specifically in the pancreas. Thus, we unveil an important role for integrins in the pancreas during autoimmune diabetes that may have important implications for the design of new therapies.

immunology