Open AccessTranscranial magnetic stimulation alters multivoxel patterns in the absence of overall activity changes
Author(s) -
Rafiei Farshad,
Safrin Martin,
Wokke Martijn E.,
Lau Hakwan,
Rahnev Dobromir
Publication year - 2021
Publication title -
human brain mapping
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.005
H-Index - 191
eISSN - 1097-0193
pISSN - 1065-9471
DOI - 10.1002/hbm.25466
Subject(s) - transcranial magnetic stimulation , stimulation , neuroscience , intensity (physics) , motor cortex , psychology , brain activity and meditation , neural activity , transcranial alternating current stimulation , prefrontal cortex , brain stimulation , dorsolateral prefrontal cortex , perception , electroencephalography , cognition , physics , quantum mechanics
Abstract Transcranial magnetic stimulation (TMS) has become one of the major tools for establishing the causal role of specific brain regions in perceptual, motor, and cognitive processes. Nevertheless, a persistent limitation of the technique is the lack of clarity regarding its precise effects on neural activity. Here, we examined the effects of TMS intensity and frequency on concurrently recorded blood‐oxygen‐level‐dependent (BOLD) signals at the site of stimulation. In two experiments, we delivered TMS to the dorsolateral prefrontal cortex in human subjects of both sexes. In Experiment 1, we delivered a series of pulses at high (100% of motor threshold) or low (50% of motor threshold) intensity, whereas, in Experiment 2, we always used high intensity but delivered stimulation at four different frequencies (5, 8.33, 12.5, and 25 Hz). We found that the TMS intensity and frequency could be reliably decoded using multivariate analysis techniques even though TMS had no effect on the overall BOLD activity at the site of stimulation in either experiment. These results provide important insight into the mechanisms through which TMS influences neural activity.