Fig. 3.

Optimization of the data length of GCaMP6f and photometry-CBV time-courses for calculating HRFs. (a) The resulting HRFs upon regression with different length (s) of GCaMP and CBV time-course. (b) High-frequency white noise ($>0.1\mathrm{Hz}$) is reduced to a steady-state when the training data are longer than $\sim 160\mathrm{s}$ (5 times the decay time constant). We defined the signals $>0.1\mathrm{Hz}$ as noise because hemodynamic activity is commonly considered to be between 0.01-0.1 Hz. Optimization of the data length of GCaMP6f and photometry-CBV time-courses for calculating HRFs (Video 2, MP4, 6 MB [URL: https://doi.org/10.1117/1.NPh.9.3.032205.2]).