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Rivlin-Etzion, M.

Publications and source records attributed to Rivlin-Etzion, M..

2 recordsLinked to original sources

Segment2P: Parameter-free automated segmentation of cellular fluorescent signals

The availability of genetically modified calcium indicators has made calcium imaging of neural signaling accessible and widespread whereby recording hundreds or even thousands of cells simultaneously is commonplace. Immunocytochemistry also produces large images with a great number of antibody labeled cells. A major bottleneck towards fully harnessing these techniques is the delineation of the neural cell bodies. We designed an online robust cell segmentation algorithm based on deep learning which does not require installation or expertise. The robust segmentation is achieved by pre-processing images submitted to the site and running them through DeepLabv3 networks trained on human segmented micrographs. The algorithm does not entail any parameter tuning; can be further trained if necessary; is robust to cell types and microscopy techniques (from immunocytochemistry to single and multi-photon microscopy) and does not require image pre-processing.

neuroscience

Antagonistic center-surround mechanisms for direction selectivity in the retina

A key feature in sensory processing is center-surround receptive field antagonism. Retinal direction-selectivity (DS) relies on asymmetric inhibition from starburst amacrine cells (SAC) to direction selective ganglion cells (DSGC). SAC exhibit antagonistic center-surround, depolarizing to light increments and decrements in their center and surround, respectively, but the role of this property in DS remains elusive. We found that a repetitive stimulation exhausts SAC center and enhances its surround and used it to distinguish center-from surround-mediated responses. Center, but not surround stimulation, induced direction-selective responses in SAC, as predicted by an elementary spatiotemporal model. Nevertheless, both SAC center and surround elicited direction-selective responses in DSGCs, but to opposite directions. Physiological and morphology-based modeling data show that the opposed responses resulted from inverted DSGCs excitatory-inhibitory temporal balance, indicating that SAC response time rules DS. Our findings reveal antagonistic center-surround mechanisms for DS, and demonstrate how context-dependent center-surround reorganization enables flexible computations.

neuroscience