Fig. 2: Pharmaco-fUSI closely tracks ketamine-evoked gamma-band power in the prefrontal cortex.

a Schematic representation of the setup for recording intracranial electrocorticography over the Cg1 sub-region of the prefrontal cortex. Coronal slice drawing adapted from the Paxinos & Watson rat brain atlas³⁰. b Representative spectrogram for i.v. administration of 10 mg/kg ketamine (KET). c Time series of normalized electrocorticography (ECoG) power changes in each frequency band and cerebral blood volume (CBV) signal in the Cg1 region. Solid lines represent the mean values and shaded areas are SEM. d For each rat, the time series of normalized ECoG power changes and the Cg1 CBV signal were regressed using a four-parameter gamma-distribution function. The fitted β₁, β₂, and β₃ values were compared between each band and Cg1 CBV time series. A time-delay parameter β₄ was added to the model to improve the goodness of fit but was not included in the statistical analysis. No significant differences were observed in the least-squares minimization residuals (Supplementary Fig. 3f; P > 0.11). Two-tailed unpaired t-test comparing each band to CBV, *corrected P < 0.05; **P < 0.01; ***P < 0.001. n = 6 rats for ECoG; n = 9 rats for CBV. Data are presented as mean +/− SEM. Source data are provided as a Source Data file. Details on the statistical analyses are provided in Supplementary Table 1.