Cortical propagation as a biomarker for recovery after stroke

Abstract

Stroke is a debilitating condition which affects millions of people worldwide. The development of improved rehabilitation paradigms rests on finding biomarkers suitable for tracking functional damage and recovery. We perform a detailed spatiotemporal analysis of wide-field calcium images from mice during longitudinal motor training before and after focal stroke induction. We define three indicators that characterise the duration, the angle of propagation and the smoothness of global movement-evoked activation patterns. During acute stroke we observe an increase in global event duration and a decrease in smoothness over the ipsilesional hemisphere. For both rehabilitation via motor training alone and combined with pharmacological therapy, we find clear signs of recovery, but surprisingly, cortical propagation in double treated mice with generalised recovery is even faster and smoother than before stroke. Our propagation-based biomarkers deliver unforeseen insight into brain mechanisms underlying motor recovery and thus pave the way towards a more targeted post-stroke therapy.