Phase sensitivity of complex cells in primary visual cortex

► Visual neurons are classified as simple or complex based on their spatial phase sensitivity. ► Classification is typically based on Fourier analysis of responses to moving sine-wave gratings. ► We show that Fourier analysis of neural responses is sensitive to the number of spikes available. ► We present a framework for assessing the significance of modulated responses to moving gratings. ► We quantify, for the first time, the prevalence of modulated responses among complex cells in V1.