A synthetic neurobiology approach to orientation selectivity
One of the most prominent features of primary visual cortical neurons is their orientation preference [1, 2]. Many competing models for the emergence of orientation preference have been proposed, from cortical self-organization  and retinally imposed tuning [2, 3] to pinning by disorder  and randomness of neuronal circuits . In the brain, feedforward and cortical circuits, which are contributing to selectivity, cannot be selectively manipulated. Having developed methods for optogenetic stimulation  and structuring  of cultured neurons, we established a synthetic biology approach for reconstituting this emergent property in a surrogate visual cortex.
We constructed a model of the early visual pathway in-silico (a) that controls a holographic photostimulation setup providing retinothalamic input to a culture of optogenetically-modified neurons (b). We monitor neural responses with a multielectrode array (MEA) [6, 7]. Stimulating the cell culture with moving gratings revealed a substantial degree of orientation tuning even in the absence of orientation tuned afferent input (c,d). We probe this orientation tuning and its origin pharmacologically and by various stimulation conditions (e). Our approach can open up a new way to experimentally dissect the influence of recurrent connections and their connectomic parameters in-vitro.
Members working within this Project:Manuel Schottdorf