1. Supplementary Online Materials for Neural Origin of Spontaneous Hemodynamic Fluctuations in Rats under Burst-Suppression Anesthesia Condition Xiao Liu, 1,2 Xiao-Hong Zhu, 1 Yi Zhang, 1 and Wei Chen 1,2, * 1 Center for Magnetic Resonance Research Department of Radiology, 2 Department of Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota, USA * To whom correspondence should be addressed Email: wei@cmrr.umn.edu@cmrr.umn.edu

2. Figure Captions (Supplementary) Figure S1 Appearance frequency of the EEG bursts as a function of isoflurane anesthesia level. The error bars stand for the standard errors across measurement runs. Figure S2 Reproducibility and reliability of the individual fMRI experimental results. The BOLD correlation maps generated based on fourteen fMRI runs from a representative rat (Rat 9) show a consistent pattern under the same condition across multiple runs, and distinct patterns between different conditions (A). For each individual, the correlation strength (between a ROI in the left S1FL and the right S1FL reference region, see Materials and Methods in the manuscript for details) was plotted as a function of anesthesia level (B). All animals show a very similar trend, and the averaged inter-subject result and statistics have been presented in the manuscript (Figure 6E). Figure S3 Reproducibility of the BOLD correlation maps. The original correlation maps from a representative rat (Rat 9) are compared with those generated based on three reorganized datasets. The comparison datasets were created by temporally under-sampling the original datasets (keeping one time point every three), only using the first half of total time points (240 image volumes), and only using the second half of total time points, respectively. All correlation maps demonstrate similar trends across different conditions with only the original ones show a relatively higher correlation power due to favorable time averaging.

3. EEG Burst Frequency (min -1 ) Anesthesia Level Figure S1

4. Dead ISO 2.2 ISO 2.0ISO 1.8 Run 1Run 2Run 3Run 4Run 1Run 2Run 3Run 4 Run 1Run 2Run 3Run 4Run 1Run 2 Correlation (r) 1.0 -0.5 0.5 A B Correlation Coefficients (r) Reliability Reproducibility Figure S2

5. Original data Lower Temporal Resolution First Half of DataSecond Half of Data Correlation Coefficient (r) 1.0 -0.3 0.3 ISO 1.8ISO 2.0ISO 2.2 Dead Figure S3