Somato-motor inhibitory processing in humans: an event-related functional MRI study

Inhibiting inappropriate behavior and thoughts is an essential ability
for humans, but the regions responsible for inhibitory processing are a
matter of continuous debate. This is the first study of somatosensory
go/nogo tasks using event-related functional magnetic resonance
imaging (fMRI). Fifteen subjects preformed two different types of
go/nogo task, i.e. (1) Movement and (2) Count, to compare with
previous studies using visual go/nogo tasks, and confirm whether the
inhibitory processing is dependent on sensory modalities. Go and nogo
stimuli were presented with an even probability. Our data indicated
that the response inhibition network involved the dorsolateral
(DLPFC) and ventrolateral (VLPFC) prefrontal cortices, pre-supplementary
motor area (pre-SMA), anterior cingulate cortex (ACC),
inferior parietal lobule (IPL), insula, and temporoparietal junction
(TPJ), which were consistent with previous results obtained using
visual go/nogo tasks. These activities existed in both Movement and
Count Nogo trials. Therefore, our results suggest that the network for
inhibitory processing is not dependent on sensory modalities but
reflects common neural activities. In addition, there were differences of
activation intensity between Movement and Count Nogo trials in the
prefrontal cortex, temporal lobe, and ACC. Thus, inhibitory processing
would involve two neural networks, common and uncommon
regions, depending on the required response mode.