(A) Schematics of awake-mouse experimental setup. (B) Reconstruction in 3D of the superficial barrel cortex from a PdgfrB-Cre RCL-GCaMP6s mouse. VSMC expressing GCaMP6s are shown in green; the vasculature loaded with Rhod B-dextran is shown in red. (C) Summary time course of arteriole diameter responses (N = 5). Arrow and vertical dotted line indicate MES (0.2 second). To limit photobleaching and/or photodamage, measurements were taken for 60 seconds every 300 seconds. Inset: Temporal close-up of percent diameter changes during the ictal (t test, t[4] = 3.74, P = 0.02) and postictal (t test, t[4] = 3.58, P = 0.023) period and representative trace of diameter in response to 0.2-second MES. (D) Summary time course of VSMC Ca²⁺ elevations in the same experiments as diameter measures. Inset: Temporal close-up of percentage VSMC Ca²⁺ changes during the ictal (t test, t[4] = 2.42, P = 0.036) and postictal (t test, t[4] = 3.03, P = 0.038) period. Inset: representative trace of VSMC Ca²⁺ in response to 0.2-second MES. (E) Cross section of a penetrating arteriole (red) with VSMC expressing GCaMP6s (green). Images show baseline (top), the ictal period (middle), and the postictal period (bottom). (F) Left: Summary of calculated Spearman’s r values between changes in arteriole diameter and VSMC Ca²⁺ during the postictal period. Right: Correlation between VSMC Ca²⁺ and arteriole diameter during baseline (100 seconds before MES) and postictal period (4500 seconds). Each data point represents a 10-second bin and averages across all 5 animals. Data represent mean ± SEM. *P < 0.05, **P < 0.01.