Neuropsychological parameters indexing executive processes are associated with independent components of ERPs

Abstract

Lesion studies have indicated that at least the three executive processes can be differentiated in the frontal lobe: Energization, monitoring and task setting. Event related potentials (ERPs) in Go/NoGo tasks have been widely used in studying executive processes. In this study, ERPs were obtained from EEG recorded during performance of a cued Go/NoGo task. The Contingent Negative Variation (CNV) and P3NoGo waves were decomposed into four independent components (ICs), by applying Independent Component Analysis (ICA) to a collection of ERPs from 193 healthy individuals. The components were named IC CNVearly, IC CNVlate, IC P3NoGoearly and IC P3NoGolate according to the conditions and time interval in which they occurred. A sub-group of 28 individuals was also assessed with neuropsychological tests. The test parameters were selected on the basis of studies demonstrating their sensitivity to executive processes as defined in the ROtman-Baycrest Battery for Investigating Attention (ROBBIA) model. The test scores were categorized into the domain scores of energization, monitoring and task setting and correlated with the amplitudes of the individual ICs from the sub-group of 28 individuals. The energization domain correlated with the IC CNVlate and IC P3NoGoearly. The monitoring domain correlated with the IC P3NoGolate, while the task setting domain correlated with the IC CNVlate. The IC CNVearly was not correlated with any of the neuropsychological domain scores. The correlations between the domains and ICs remained largely unchanged when controlling for full-scale IQ. This is the first study to demonstrate that executive processes, as indexed by neuropsychological test parameters, are associated with particular event-related potentials in a cued Go/NoGo paradigm.

Modulation of ERP components by task instructions in a cued go/no‐go task

“…It is therefore improbable that the component reflects response inhibition, which should always occur before the mean point in time when responses are executed. Brunner et al () suggested that this component might rather reflect the process of replacing the prepared go response with an alternative response. Given the high level of attention toward the dominant task set (as reflected in the amplitude of the IC CNV late ) in the speed condition, it is reasonable to expect that implementation of the subdominant task set (P = no‐go), requires more energization in the speed than in the accuracy condition.…”

“…They suggested that these components might independently reflect the proposed inhibitory and evaluative functions of the P3no‐go. In a follow‐up study, however, the inhibitory hypothesis of the IC P3no‐go early was not supported, whereas the monitoring hypothesis of the IC P3no‐go late was supported (Brunner et al, ). Rather than being related to inhibition, it was suggested that the IC P3no‐go early might reflect implementation of an alternative, subdominant task set.…”

“…When interstimulus intervals are short, the early and late CNV cannot be identified as separate components in the raw ERP. These components can, however, be separated by using ICA, even in paradigms with 1‐s interstimulus intervals (Brunner et al, ; Jervis et al, ).…”

“…Brunner et al () demonstrated that the IC P3no‐go early correlated significantly with neuropsychological indexes of energization, including reaction time. This finding could indicate that the IC P3no‐go early may be the subcomponent of the P3no‐go that is modulated by response speed.…”

“…Unlike the early CNV, this component has been found to be larger under instructions for speed than for accuracy (Loveless & Sanford, 1974). Because it is modulated in response to time pressure, this potential has been suggested to be facilitated by effortful allocation of attention (Falkenstein, Hoormann, Hohnsbein, & Kleinsorge, 2003), or energization (Brunner et al, 2015). We prefer the concept of energization because it is specified as a facilitation process that is under voluntary control, and required for initiating and maintaining responses (Stuss & Alexander, 2007).…”