Extended Data Fig. 9: Two-photon photostimulation-triggered spine mapping.

a, Example dendrite and ROIs used for spine fluorescence extraction. Same experiment as shown in Fig. 4, where panel f shows a section of the FOV shown here at higher magnification. b, Fluorescence from six example ROIs. c, Photostimulation responses of example ROI #1 plotted against the mean photostimulation response across all spine ROIs. Trials that produced independent activity were identified as passing a threshold applied to signals from that spine and not passing a threshold applied to the average spine. Targets active on those trials, like the example target #1095 shown, were identified. d, Four example spines from four recordings. Top, stimulation-triggered average image showing independently activated spines. Bottom, the stimulation triggered fluorescence traces from those example spines. e, An example spine and stimulation target pair that were identified in two separate experimental sessions, 3 days apart. f, Distribution of retinotopic and physical distances between effective target in LM and the parent soma of the responsive spine. Retinotopic distances were measured using widefield intrinsic imaging under anaesthesia and temporal retinotopic mapping (Kalatsky et al., 2003). g, Retinotopic position of effective targets in LM plotted relative to the retinotopic position of the parent soma of the responsive spine, positioned at the origin.