Comparing neural response to painful electrical stimulation with functional MRI at 3 and 7 T

Abstract Progressing from 3 T to 7 T functional MRI enables marked improvements of human brain imaging in vivo . Although direct comparisons demonstrated advantages concerning blood oxygen level dependent (BOLD) signal response and spatial specificity, these mostly focused on single brain regions with rather simple tasks. Considering that physiological noise also increases with higher field strength, it is not entirely clear whether the advantages of 7 T translate equally to the entire brain during tasks which elicit more complex neuronal processing. Therefore, we investigated the difference between 3 T and 7 T in response to transcutaneous electrical painful and non-painful stimulation in 22 healthy subjects. For painful stimuli vs. baseline, stronger activations were observed at 7 T in several brain regions including the insula and supplementary motor area, but not the secondary somatosensory cortex (p  vs. non-painful stimulation limited the differences between the field strengths to the periaqueductal gray (PAG, p