Fig. 3: Two-photon calcium imaging of soma, dendrites, spines and boutons.
From: The Cousa objective: a long-working distance air objective for multiphoton imaging in vivo
a, Population calcium imaging (GCaMP6s) over a 1.7-mm-wide FOV. Traces from cells within boxes at left are expanded at right, a selection of the 1,648 neurons detected in this dataset. b, In a mouse with ultra-sparse expression of GCaMP8m in V1, we imaged calcium transients in putative axonal boutons (B), dendritic spines (S) and dendritic shafts during the presentation of visual stimuli (drifting gratings). Color codes show the orientation preference of each ROI. bAP-associated calcium transients detected in the dendrite were subtracted from the dendritic spine S1 signal, revealing activity events that are independent from local bAP signals, indicative of local synaptic input. Orientation tuned responses were reliable for spines S1 and S2, boutons B1 and B2, and the nearby dendrite (n = 15 repeats per stimulus; mean in black ± s.e.m. in gray). Responses in axonal bouton B2 varied with contrast (contrast levels of 40% in blue, 70% in orange and 100% in black; mean ± s.e.m.; n = 5 repeats).
