Fig. 2: Measuring spectral and spatial RFs with two-photon calcium imaging of GCaMP6f.

a Average image from the first trial (40 s). b The local cross-correlation image was used to identify groups of pixels that have common temporal dynamics. Four examples of manually selected neurons are outlined in red. Their mean responses are shown in panels to the right. c Illustration of the random grating stimulus. d Time courses from one trial of the four example cells in a. e Mean and SE of response following stimulus onset. The two traces in each panel correspond to the orientation/SF combination that elicited the largest (black) and smallest (gray) response. f Color map indicating the normalized response to each orientation and SF in the ensemble. Responses were averaged over spatial phase. The color range spans the minimum (blue) to maximum (red) response of each cell. g Orientation tuning curve (black dots) computed by taking a weighted sum over the SF dimension. Gaussian fit is in red. h Same as g, but for SF. Fit is a difference-of-Gaussian. i Spatial phase tuning curve for the orientation and SF that elicited the largest mean response. The fit is a sine wave. j Illustration of the random bar stimulus. k Time courses from one trial of the four example cells in a. l Mean and SE response after onset of the bar that elicits the largest (black) and smallest (gray) response. m Grayscale image is the addition of the ON and OFF spatial RF; i.e. the “spatial envelope”. The half-max contour of the ON and OFF 2D Gaussian fits are shown in red and blue, respectively. n The ON and OFF orientation tuning curves (black), measured by averaging over the position dimension, with Gaussian fits (red and blue). o The ON and OFF line weighting functions (black) taken at each cell’s optimal orientation, with Gaussian fits (red and blue). This experiment was performed once in three different regions-of-interest, in two animals.