Abstract #0724

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

Karen 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.