Abstract #1603

Assessment of Rat Barrel Cortex BOLD Responses After Trigeminal Nerve Stimulation. on the Linearity of BOLD FMRI Changes Against Neuronal Activity in the Barrel Cortex

Nathalie Just^1,2, Stephane Germain^1,2, Martin Lauritzen^3,4, Rolf Gruetter^1,2

¹LIFMET, CIBM, EPFL, Lausanne, Switzerland; ²Department of Radiology, UNIL and HUG, Lausanne and Geneva, Switzerland; ³Department of Clinical Neurophysiology, Glostrup Hospital, Glostrup, Denmark; ⁴Department of Medical Physiology, Panum Institute and University of Copenhafen, Copenhagen, Denmark

The present study examined the BOLD fMRI response of the rat barrel cortex upon trigeminal nerve stimulation. BOLD changes as a function of current intensity and stimulus frequency were measured under α -chloralose anesthesia. The BOLD responses showed non-linear behavior as a function of current intensity and stimulus frequency that can be compared to the non-linear patterns found for cerebral blood flow and local field potentials measured in the barrel cortex as a function of the same stimulus parameters and stimulation model. Linear coupling between the neuronal and BOLD responses cannot be generalized for every condition or brain region.