Abstract #1615

Dependencies of the Negative BOLD Signal in Primary Somatosensory Cortex on Stimulation Intensity and Duration

Katharina Schaefer¹, Henrik Bo Wiberg Larsson¹, Martin Lauritzen^2,3

¹Department of Clinical Physiology and Nuclear Medicine, Glostrup Hospital, Glostrup, Denmark; ²Department of Clinical Neurophysiology, Glostrup Hospital, Glostrup, Denmark; ³Department of Medical Physiology, The Panum Institute, University of Copenhagen, Copenhagen, Denmark

Unilateral electrical stimulation of the somatosensory system was performed in high and low stimulation intensities. High intensity stimulation elicited a positive contralateral and a negative ipsilateral BOLD signal in the primary somatosensory cortex (SI). Additionally a spatially extensive negative BOLD signal was found in the parietal and occipital cortex. This negative BOLD signal might represent functional inhibition of the sensory map of the human body.