Download a PDF of the 2012 Annual Report - Black Dog Institute

Research activity from 2012 includes:Hemodynamic travelling waves in humanvisual cortex – Functional magnetic resonanceimaging (fMRI) experiments have advancedour understanding of the structure and functionof the human brain. Dynamic changes in the flowand concentration of oxygen in blood are observedexperimentally in fMRI data via the blood oxygenlevel dependent (BOLD) signal. Since neuronal activityinduces this hemodynamic response, the BOLD signalprovides a non-invasive measure of neuronal activity.Understanding the mechanisms that drive this BOLDresponse is fundamental for accurately inferring theunderlying neuronal activity. The goal of this study isto systematically predict spatiotemporal hemodynamicsfrom a biophysical model, then test these in a highresolution fMRI study of the visual cortex. Using thistheory, we predict and empirically confirm the existenceof hemodynamic waves in cortex – a striking andnovel finding.Neural mechanisms of intermuscularcoherence: Implications for the rectification ofsurface electromyography – This study employeda computational model to look at the role of the motorunit action potential (MAUP) on the translation of‘oscillatory activity’. (Oscillatory activity plays a crucialrole in corticospinal control of muscle synergies.) Thiswas tested and compared to test results from intermuscularcoherence between bilateral leg muscles.The model shows that the effect of electromyographyrectification depends on the uniformity of MUAPshapes. The data provided support for a heterogeneousdistribution of MUAPs which implies that theshape of MUAPs is an essential parameter to reconcileexperimental and computational approaches.BLACK DOG 201225