Inhibition-Related ERP Components: Variation with Modality, Age, and Time-on-Task

Abstract

In Go/Nogo tasks, the ERP after Nogo stimuli generally reveals a negativity (Nogo-)N2 and a subsequent positivity (Nogo-)P3 over fronto-central scalp regions. These components are probably related to different subprocesses serving response inhibition, namely, modality-specific and general inhibition, respectively. In the present study we investigate whether aging or prolonged work (“time-on-task”) have an effect on N2 and P3. Twelve young and 12 elderly subjects performed simple Go/Nogo tasks to visual or auditory letter stimuli. Reaction times were longer after visual than after auditory stimuli, and longer in the elderly than in the young. The ERP results reveal a slight impairment of modality-specific inhibition (N2) in the elderly after visual, but not after auditory, stimuli. General inhibition (P3) was delayed in the elderly for both modalities, as was Go-P3 and RT. Hence, it appears that the response slowing of the elderly is the result of a slowing of the decision process whether to respond or to inhibit. Moreover, age appears to affect both aspects of inhibition in a different manner. No effects of time-on-task were found, which suggests that the inhibitory processes are fairly robust against mental fatigue.

Executive brain functions after exposure to nocturnal traffic noise: effects of task difficulty and sleep quality

“…The Nogo-N2 has been considered as an index of pre-motor inhibitory control (Kok 1999;Falkenstein et al 1999Falkenstein et al , 2002 or monitoring of a conflict between pre-motor response representations, namely response versus no-response presentations (Nieuwenhuis et al, 2003). We found only a marginally significant reduction of the Nogo-N2 component after nocturnal noise in the difficult task only (Fig.…”

“…During the tests in the morning two EEG channels (Fz, Pz), from which the ERPs were computed, and two EOGs were recorded. The channels were selected to minimize preparation time, while covering the most relevant sites for ERPs in the Go/Nogo task (Falkenstein et al 2002).…”

“…In addition to Go-and Nogo-ERPs, difference ERPs (Nogo minus Go) were computed, resulting in difference components N2d and P3d. A recent study by Falkenstein et al (2002, Fig. 3 and Fig.…”

“…This was possible for the P3, while for the N2, a negativity in the Nogo-N2 window was often not detectable. Hence, for the N2 we measured the amplitude of the ERP for Nogo and Go trials at Fz at the time of the negative maximum of the N2d (Falkenstein et al 2002). All amplitudes were measured relative to the prestimulus baseline of 100 ms length.…”

“…These components are supposed to be indices of different aspects of inhibition originating in the prefrontal cortex (Pfefferbaum et al 1985;Jodo and Kayama 1992;Falkenstein et al 1999;Bokura et al 2001, Kok 1999Bruin et al 2001;Nieuwenhuis et al 2003;Burle et al 2004). The Nogo-N2 is not dependent on an overt response (Burle et al 2004); it reflects either a pre-motor inhibition process (Kok 1999;Falkenstein et al 1999Falkenstein et al , 2002 or the detection of the conflict between concurrent pre-motor action tendencies, i.e., Go and Nogo (Nieuwenhuis et al 2003). Hence, it can be related to premotor performance monitoring and control mechanism.…”