RT Journal Article
SR Electronic
T1 Visually driven neuropil activity and information encoding in mouse area V1
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 113019
DO 10.1101/113019
A1 Sangkyun Lee
A1 Jochen F. Meyer
A1 Stelios M. Smirnakis
YR 2017
UL http://biorxiv.org/content/early/2017/03/06/113019.abstract
AB Spontaneous calcium fluorescence recorded from large cortical neuropil patches strongly correlates with the electro-corticogram, and is thought to arguably reflect primarily pre-synaptic inputs. Here we used in vivo 2-photon imaging with Oregon Green Bapta (OGB) to study neuropil visual responses to moving gratings in layer 2/3 of mouse area V1. We found neuropil responses to be more reliable and more strongly modulated than neighboring somatic activity. Furthermore, stimulus independent modulations in neuropil activity, i.e. noise correlations, were highly coherent across the cortical surface, up to distances of at least 200 μm. Pairwise neuropil-to-neuropil-patch noise correlation strength was much higher than cell-to-cell noise correlation strength and depended strongly on brain state, decreasing in quiet wakefulness relative to light anesthesia. The profile of neuropil noise correlation strength decreased gently with distance, dropping by ~12% at a distance of 200 μm. This was comparatively slower than the profile of cell-to-cell noise correlations, which dropped by ~30% at 200 μm. Interestingly, in spite of the “salt & pepper” organization of orientation and direction encoding across mouse V1 neurons, populations of neuropil patches, even of moderately large size (radius ~100μm), showed high accuracy for discriminating perpendicularly moving gratings commensurate to the accuracy of corresponding cell populations. These observations underscore the dynamic nature of the functional organization of neuropil activity.Conflict of Interest The authors declare that no competing interests exist.