Frontal and parietal activities associated with different inhibitory
processes in a Stroop-matching/stop-signal task: a channel-wise fNIRS
study
Abstract
Inhibition is an important component of cognitive control that
encompasses multiple processes, such as interference control, inhibition
of prepotent responses and suppression of ongoing responses. Frontal and
temporoparietal regions of the cortex are implicated differently in
inhibitory functions. The Stroop-matching/stop-signal task is a recent
task that uses Stroop stimuli and stop-signals to create conditions that
allow the investigation of the three forms of inhibition aforementioned.
The task provides a way to distinguish the effect of these inhibitions
as well as their interactions using a single task. The present study
used functional near-infrared spectroscopy (fNIRS) to assess frontal and
temporoparietal activations during the Stroop-matching/stop-signal task.
The main objective was to investigate which cortical regions each
inhibitory function would recruit during this task. Fifty-two young
adults (mean age = 21.4, SD = 3.44) participated. Performance results
indicated the effects previously found in the
Stroop-matching/stop-signal task. FNIRS results showed that the left
inferior frontal cortex (IFC) and the bilateral intraparietal sulcus
(IPS) are involved in interference control; the left IFC also showed
activation in inhibition of prepotent responses; and the right IFC was
involved in the suppression of ongoing responses. The interaction
between suppression of responses and the other two forms of inhibition
lead to deactivation of frontal and parietal areas. Thus, each form of
inhibition demanded by the Stroop-matching/stop-signal task seems to
recruit specific cortical regions, supporting the distinction between
inhibitory components at the neurophysiological level.