Somato-motor inhibitory processing in humans: An event-related functional MRI study (original) (raw)
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When ‘go’ and ‘nogo’ are equally frequent: ERP components and cortical tomography
European Journal of Neuroscience, 2004
In human electrophysiology, a considerable corpus of studies using event-related potentials have investigated inhibitory processes by employing the 'go-nogo' paradigm, which requires responding to one type of event while withholding the response to another type of event. Two event-related potential waveform features (N2 and P3) have been associated with larger amplitude in nogo trials than in go trials. Traditionally, these differences were thought to reflect response inhibition. Recently, the source localization of N2 to the anterior cingulate cortex, as well as the colocalization of N2 with error-related negativity, has been interpreted in terms of conflict monitoring. In order to isolate the contribution of inhibitory processes, we matched the frequency of the go and nogo events, thus minimizing differences in response conflict between event types. A data-driven analytical procedure contrasted go with nogo events across the entire event-related potential segment and found that N2 reliably differentiated between the two conditions while P3 did not. Tomographical analyses of the N2 difference observed in conditions of equal go and nogo trial frequency localized N2 to the right ventral and dorsolateral prefrontal cortex. Because a growing body of evidence implicates these brain regions in inhibitory processes, we conclude that N2 does, at least in part, reflect inhibition.
The NoGo-anteriorization as a neurophysiological standard-index for cognitive response control
International Journal of Psychophysiology, 1999
. Event related potentials ERPs during the Go-and the NoGo-condition of the Continuous Performance Test Ž . CPT were applied to investigate the neurophysiological basis of cognitive response control. These conditions of the test represent the execution and the inhibition of an anticipated motor response. In a previous study, the comprehensive spatial analysis of the ERPs allowed to define a parameter which robustly reflected the anterioriza-Ž . tion of the positive P300 field area during the NoGo-compared to the Go-condition NoGo-anteriorisation, NGA . The result was found consistently in all investigated subjects. The present study replicated the finding in 27 healthy subjects without any exception. Moreover, the latencies were longer and the amplitudes showed a trend to be higher in the NoGo-compared to the Go-ERP. This is interpreted as a sign of higher processing demands in the NoGo-condition. In conclusion, the ability of the NGA to express reliably the differences of brain activity leading to execution or suppression of a prepared motor response qualifies this parameter as a topographical standard-index for cognitive response control. ᮊ
Proactive Control Strategies for Overt and Covert Go/NoGo Tasks: An Electrical Neuroimaging Study
Proactive and reactive inhibition are generally intended as mechanisms allowing the withholding or suppression of overt movements. Nonetheless, inhibition could also play a pivotal role during covert actions (i.e., potential motor acts not overtly performed, despite the activation of the motor system), such as Motor Imagery (MI). In a previous EEG study, we analyzed cerebral activities reactively triggered during two cued Go/NoGo tasks, requiring execution or withholding of overt or covert imagined actions, respectively. This study revealed activation of pre-supplementary motor area (pre-SMA) and right inferior frontal gyrus (rIFG), key nodes of the network underpinning reactive inhibition of overt responses in NoGo trials, also during MI enactment, enabling the covert nature of the imagined motor response. Taking into account possible proactive engagement of inhibitory mechanisms by cue signals, for an exhaustive interpretation of these previous findings in the present study we analyzed EEG activities elicited during the preparatory phase of our cued overt and covert Go/NoGo tasks. Our results demonstrate a substantial overlap of cerebral areas activated during proactive recruitment and subsequent reactive implementation of motor inhibition in both overt and covert actions; also, different involvement of pre-SMA and rIFG emerged, in accord with the intended type (covert or overt) of incoming motor responses. During preparation of the overt Go/NoGo task, the cue is encoded in a pragmatic mode, as it primes the possible overt motor response programs in motor and premotor cortex and, through preactivation of a pre-SMA-related decisional mechanism, it triggers a parallel preparation for successful response selection and/or inhibition during the response phase. Conversely , the preparatory strategy for the covert Go/NoGo task is centered on priming of an inhibitory mechanism in rIFG, tuned to the instructed covert modality of motor performance and instantiated during subsequent MI, which allows the imagined response to remain a potential motor act.
A large scale (N=102) functional neuroimaging study of response inhibition in a Go/NoGo task
Behavioural Brain Research, 2013
We report a functional magnetic resonance imaging (fMRI) study of 102 healthy participants who completed a demanding Go/NoGo task. The primary purpose of this study was to delineate the neural systems underlying responses to errors in a large sample. We identified a number of regions engaged during error processing including the anterior cingulate, left lateral prefrontal areas and bilateral inferior frontal gyrus, and the subthalamic nucleus. The power afforded by the large cohort enabled identification of regions not consistently measured during Go/NoGo tasks thus helping to incrementally refine our understanding of the neural correlates of error processing. With the present fMRI results, in combination with our previous exploration of response inhibition (Steele et al. [1]), we outline a comprehensive set of regions associated with both response inhibition and error processing.
Somatosensory off-response in humans: an ERP study
Experimental Brain Research, 2008
Quick detection of changes in the sensory environment is very important for survival, resulting in automatic shifts of attention to the event and the facilitation of subsequent processes to execute appropriate behaviors. The abrupt onset or oVset of a sensory stimulus should also activate the neural network detecting changes. To test this hypothesis, we compared cortical on-and oV-responses using somatosensory-evoked potentials (SEPs) elicited by a train of electrical pulses delivered to the right hand in eight healthy volunteers. SEPs were recorded from 15 electrodes on the scalp at three diVerent interstimulus intervals (ISIs, 50, 20, and 10 ms) under two sets of conditions (attended and unattended). Both the onset and oVset of stimulation evoked two similar components, P100 and N140, in the attended and unattended conditions. The latency of P100 and N140 in response to stimulus onset did not diVer among the three ISIs, while the latency of both components in response to stimulus oVset was signiWcantly longer for the longer ISI; that is, detection of the cessation of the stimulation was based on short-term memory of the stimulus frequency. The present results supported a cortical network triggered by both the onset and oVset of sensory stimulation. In this network, the change is automatically detected using a memory trace by comparing the abrupt event (on or oV) with the preceding condition (silent or repetitive stimuli).
NeuroImage, 2011
The anterior N2 and P3 waves of event related potentials (ERPs) in the GO/NOGO paradigm in trials related to preparatory set violations in previous studies were inconsistently associated either with action inhibition or conflict monitoring operations. In the present study a paired stimulus GO/NOGO design was used in order to experimentally control the preparatory sets. Three variants of the same stimulus task manipulated sensory mismatch, action inhibition and conflict monitoring operations by varying stimulus-response associations. The anterior N2 and P3 waves were decomposed into components by means of independent component analysis (ICA). The ICA was performed on collection of 114 individual ERPs in the three experimental conditions. Three of the independent components were selectively affected by the task manipulations indicating association of these components with sensory mismatch, action inhibition and conflict monitoring operations. According to sLORETA the sensory mismatch component was generated in the left and right temporal areas, the action suppression component was generated in the supplementary motor cortex, and the conflict monitoring component was generated in the anterior cingulate cortex.