Unsupervised Spike Sorting for Large-Scale, High-Density Multielectrode Arrays

We present a method for automated spike sorting for recordings with high-density, large-scale multielectrode arrays. Exploiting the dense sampling of single neurons by multiple electrodes, an efficient, low-dimensional representation of detected spikes consisting of estimated spatial spike locations and dominant spike shape features is exploited for fast and reliable clustering into single units. Millions of events can be sorted in minutes, and the method is parallelized and scales better than quadratically with the number of detected spikes. Performance is demonstrated using recordings with a 4,096-channel array and validated using anatomical imaging, optogenetic stimulation, and model-based quality control. A comparison with semi-automated, shape-based spike sorting exposes significant limitations of conventional methods. Our approach demonstrates that it is feasible to reliably isolate the activity of up to thousands of neurons and that dense, multi-channel probes substantially aid reliable spike sorting

Pan-retinal characterisation of Light Responses from Ganglion Cells in the Developing Mouse Retina

International audienceWe have investigated the ontogeny of light-driven responses in mouse retinal ganglion cells (RGCs). Using a large-scale, high-density multielectrode array, we recorded from hundreds to thousands of RGCs simultaneously at pan-retinal level, including dorsal and ventral locations. Responses to di erent contrasts not only revealed a complex developmental pro le for ON, OFF and ON-OFF responses, but also unveiled di erences between dorsal and ventral RGC responses. At eye-opening, dorsal RGCs of all types were more responsive to light, perhaps indicating an environmental priority to nest viewing for pre-weaning pups. The developmental pro le of ON and OFF responses exhibited antagonistic behaviour, with the strongest ON responses shortly after eye-opening, followed by an increase in the strength of OFF responses later on. Further, we found that with maturation receptive eld (RF) center sizes decrease, spike-triggered averaged responses to white noise become stronger, and centers become more circular while maintaining di erences between RGC types. We conclude that the maturation of retinal functionality is not spatially homogeneous, likely re ecting ecological requirements that favour earlier maturation of the dorsal retina

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Ermittlung der Investitionskosten von Chemieanlagen in verschiedenen Projektphasen

SIGLEAvailable as manuscript MS 1297/84 from VCH Verlagsges., Weinheim (Germany, F.R.) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman