Tight Coupling of Resting-state BOLD fluctuations with Intracortical DC Changes in Rat Somatosensory Cortex during Prolonged Medetomidine Sedation

medetomidine from isoflurane) indicated dynamic changes in BOLD low-frequency power. Within the first hour of medetomidine administration, the BOLD power was highest at < 0.1 Hz, as previously observed in human resting-state studiesl. However, the power of <0.1-Hz decreased and a peak at ~0.2-Hz increased over time (Fig. 1). The 0.2-Hz peak was observed for the rest of the experiment (up to 5 hours). The correlation between the BOLD signal and neural activity was further estimated for both peaks (<0.1-Hz, 0.2-Hz and 0.4-Hz as the control, Fig. 2A, B and C). We found the time-lagged BOLD signals at the voxels near the recording site showed significant correlation with DC signals at frequency of both <0.1-Hz and 0.2-Hz (Fig. 2). Interestingly, the 0.2-Hz peak exhibited stronger coherence with BOLD fluctuations at same frequency range (Fig. 2B). The LFP (theta/delta) powers also exhibited correlation with the BOLD signal, but less than DC. Tight Coupling of Resting-state BOLD fluctuations with Intracortical DC Changes in Rat Somatosensory Cortex during Prolonged Medetomidine Sedation