Subcortical and Cortical Distribution of BOLD Signal from Somatosensory Stimulation in Anaesthetised Rats

Diana Cash¹, Tobias C. Wood¹, Camilla Simmons¹, Aisling L. Dixon¹, Steve C.R. Williams¹, Michel B. Mesquita¹

Forepaw sensory stimulation at 0.5 and 3 Hz in alpha-chloralose-anaesthetized rats was characterized by BOLD-sensitive fMRI. An expected increase in BOLD signal in S1 contralateral cortex was detected at 3Hz, but not at 05Hz where the signal timecourse showed a trend toward decrease. S1 and other areas adjacent to the contralateral S1, as well as the ipsilateral S1 and S2 also showed decreased BOLD signal with both stimulations paradigms. Bilateral subcortical thalamic and striatal BOLD increases were also detected and similar under both stimulation frequencies.