Combining mGRASP and Optogenetics Enables High-Resolution Functional Mapping of Descending Cortical Projections

• DOI: 10.1016/j.celrep.2018.06.076
• Publication Date: 2018-07-24T17:08:29Z
• Authors: Jun Ho Song; Diana Lucaci; Ioana Calangiu; Matthew T.C. Brown; Jin Sung Park; Jinhyun Kim; Stephen G. Brickley; Paul Chadderton
• Keywords: Biological neural network; Channelrhodopsin

We have applied optogenetics and mGRASP, a light microscopy technique that labels synaptic contacts, to map the number strength of defined corticocollicular (CC) connections. Using we show CC projections form small, medium, large synapses, both distribution synapse size vary among IC regions. optogenetics, low-frequency stimulation axons expressing channelrhodopsin produces prolonged elevations miniature EPSC (mEPSC) rate. Functional analysis mEPSCs reveals small-, medium-, large-amplitude events mirror distributions observed with mGRASP. Our results reveal descending ipsilateral dominate feedback via an increased especially onto soma neurons. This study highlights feasibility combining (i.e., mGRASP) weighting at level single neurons, enabling functional connectomic mapping in diverse neural circuits.