Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.05.04.076224v1?rss=1 Authors: EL Tabbal, M., Niekisch, H., Henschke, J. J., Budinger, E., Frischknecht, R., Deliano, M., Happel, M. F. K. Abstract: In the adult vertebrate brain, long-lasting structural tenacity of synaptic networks is supported by the extracellular matrix (ECM), which is formed during brain maturation. Enzymatic removal of the ECM in cortical areas has been increasingly recognized to promote or modulate juvenile forms of plasticity, learning, and memory recall in the adult brain. However, the underlying impact of local removal of the ECM on the cortical circuit processing is still not understood. Here, we removed the ECM in the primary auditory cortex (ACx) of adult Mongolian gerbils using local injections of hyaluronidase (HYase). We performed laminar current-source density (CSD) analysis during spontaneous and evoked columnar activity and found layer-specific changes with higher activation of supragranular layers I/II and lower activity in infragranular layers Vb. Further, ECM removal induced a higher activity spread via lateral corticocortical circuits, which led to increased spectral integration at a cortical patch. A multitaper spectral analysis of layer-specific CSD responses revealed increased evoked oscillatory power in the beta band (25-36 Hz) selectively within infragranular layers Vb. Finally, to reveal the dynamic nature of translaminar interactions, we used time-domain conditional Granger causality (GC) confirming altered translaminar input-output dynamics with a supragranular lead of the columnar response profile. Our findings thus reveal new insights on how ECM modulation affects laminar cortical network dynamics, which help to interpret existing behavioral findings and to design more targeted translative applications in neurorehabilitation. Copy rights belong to original authors. Visit the link for more info