The accuracy of membrane potential reconstruction

35 A common technique used to study the response selectivity of neurons is to measure 36 the relationship between sensory stimulation and action potential responses. Action 37 potentials, however, are only indirectly related to the synaptic inputs that determine the 38 underlying, subthreshold, response selectivity. We present a method to predict 39 membrane potential the measurable result of the convergence of synaptic inputs 40 based on spike rate alone, and then test its utility by comparing predictions to actual 41 membrane potential recordings from simple cells in primary visual cortex. Using a noise 42 stimulus, we found that spike rate receptive fields were in precise correspondence with 43 membrane potential receptive fields (R=0.8). On average, spike rate alone could 44 predict 44% of membrane potential fluctuations to dynamic noise stimuli, demonstrating 45 the utility of this method to extract estimates of subthreshold responses. We also found 46 that the nonlinear relationship between membrane potential and spike rate could also 47 be extracted from spike rate data alone by comparing predictions from the noise 48 stimulus to the actual spike rate. Our analysis reveals that linear receptive field models 49 extracted from noise stimuli accurately reflect the underlying membrane potential 50 selectivity and thus represent a method to generate estimates of the underlying average 51 membrane potential from spike rate data alone. 52