%0 Journal Article %A Oliver Braganza %A Daniel Müller-Komorowska %A Tony Kelly %A Heinz Beck %T Quantitative properties of a feedback circuit predict frequency-dependent pattern separation %D 2019 %R 10.1101/813188 %J bioRxiv %P 813188 %X Feedback inhibitory motifs are important for pattern separation in several species. How feedback circuits implement pattern separation of biologically plausible, temporally structured input in mammals is poorly understood, partly because the spatiotemporal organization of the net output of these circuits has not been characterized. We have quantitatively determined key properties of net feedback inhibition in the mouse dentate gyrus, a region critically involved in pattern separation. Feedback inhibition is recruited steeply with a low dynamic range (0 to 4% of active GCs), and with a non-uniform spatial profile. Additionally, net feedback inhibition shows frequency-dependent facilitation, driven by strongly facilitating mossy fiber inputs. Computational analyses show a significant contribution of the feedback circuit to pattern separation of theta modulated inputs, even within individual theta cycles. Moreover, pattern separation was selectively boosted at gamma frequencies, in particular for highly similar inputs. This effect was highly robust, suggesting that frequency dependent pattern separation is a key feature of the feedback inhibitory microcircuit. %U https://www.biorxiv.org/content/biorxiv/early/2019/10/21/813188.full.pdf