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Abstract #0184

BOLD Impulse Response Functions and Baseline-Dependent Response Adaptation

Basavaraju G. Sanganahalli1, Peter Herman1,2, Hal Blumenfeld3, Fahmeed Hyder4

1Diagnostic Radiology, Yale University, New Haven, CT, United States; 2Human Physiology, Semmelweis University, Budapest, Hungary; 3Neurology, Neurosurgery and Neuroscience, Yale University, New Haven, CT, United States; 4Diagnostic Radiology and Biomedical Engineering, Yale University, New Haven, CT, United States

BOLD impulse response functions (IRFs) show variability (i.e, presence/absence of a delayed undershoot) across different conditions (e.g., stimuli, regions). Could these BOLD-IRF differences be due to the systems variable adaptive properties, which are known to differ with baseline? Extracellular data were compared with BOLD signal (11.7T) during forepaw stimulation under domitor and α-chloralose anesthesia in rats. BOLD-IRFs were nearly identical in the early phase but different in the late phase. Domitor, where responses are more adapted, featured a long time-constant undershoot. These results suggest that the late phase could potentially represent differences in adaptive properties across baseline states.