Estimating Hemodynamic Response Function Using Simultaneous fMRI and Calcium Recording

Abstract

· Evoked BOLD and calcium signals were recorded in the visual pathway using standard (TR=1s) and ultrafast (TR=0.3s) EPI of two TEs. · Hemodynamic response function was estimated based on neuronal calcium activity. HRF estimated from ultrafast fMRI shows faster kinetics in the lateral geniculate nucleus than the visual cortex. · BOLD signal was predicted from calcium signal convoluted by HRF. Using ultrafast fMRI significantly improved the accuracy of the predicted BOLD.