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Abstract #0724

BOLD & CBF Post-Stimulus Undershoots Are Correlated with Post-Stimulus Neuronal Activity in Humans.

MAGNA25Karen J. Mullinger1, Stephen D. Mayhew2, Andrew P. Bagshaw2, Richard W. Bowtell1, Susan T. Francis1

1SPMMRC, School of Physics and Astronomy, University of Nottingham, Nottingham, Nottinghamshire, United Kingdom; 2BUIC, School of Psychology, University of Birmingham, Birmingham, United Kingdom

The exact nature of the vascular and neuronal contributions to the BOLD post-stimulus undershoot remains unclear. Here we use simultaneous EEG-BOLD-ASL recordings during median nerve stimulation to investigate the origin of the post-stimulus undershoot. We demonstrate for the first time that the undershoot amplitudes of both BOLD and CBF measurements in contralateral (positive response) and ipsilateral (negative response) sensory-motor cortex are negatively correlated with natural fluctuations in the power of 8-13Hz, post-stimulus, mu oscillations measured from concurrent EEG recordings. This study provides new evidence for a neural component underlying the BOLD undershoot.