Cognitive reserve (CR) is a key factor to mitigate the cognitive decline during the aging process. Here, we used event-related potentials to target the preparatory brain activities associated with ...different levels of CR during visuo-motor simple response tasks (SRTs) and discriminative response tasks (DRTs). EEG was recorded from 28 healthy old (Age: 72.2 ± 4.7 years) and 14 young (Age: 22.2 ± 2.4 years) individuals during an SRT and a DRT. Depending on the CR median score, old participants were divided into either a high (High-CR) or a low CR (Low-CR) group. Behavioral performance and electrophysiological data were compared across the 3 groups. Compared with the Low-CR, the High-CR group showed larger prestimulus prefrontal (prefrontal negativity) and premotor activity (Bereitschaftspotential–BP), in the SRT, and increased premotor readiness (BP), in the DRT. The High-CR was faster and more accurate than the Low-CR group in the DRT and SRT, respectively. The High-CR group revealed enhanced brain preparatory activities that, paralleled to their behavioral performance, might reflect neural compensation and maintenance effects possibly counteracting the age-related decline in cognitive functioning.
•High cognitive reserve is associated with enhanced brain preparatory activities.•Enhanced behavioral performance was observed in individuals with high cognitive reserve.•Event-related potentials and behavioral results suggest neural compensation and maintenance effects.
The event-related potential (ERP) literature described two error-related brain activities: the error-related negativity (Ne/ERN) and the error positivity (Pe), peaking immediately after the erroneous ...response. ERP studies on error processing adopted a response-locked approach, thus, the question about the activities preceding the error is still open. In the present study, we tested the hypothesis that the activities preceding the false alarms (FA) are different from those occurring in the correct (responded or inhibited) trials. To this aim, we studied a sample of 36 Go/No-go performers, adopting a stimulus-locked segmentation also including the pre-motor brain activities. Present results showed that neither pre-stimulus nor perceptual activities explain why we commit FA. In contrast, we observed condition-related differences in two pre-response components: the fronto-central N2 and the prefrontal positivity (pP), respectively peaking at 250ms and 310ms after the stimulus onset. The N2 amplitude of FA was identical to that recorded in No-go trials, and larger than Hits. Because the new findings challenge the previous interpretations on the N2, a new perspective is discussed. On the other hand, the pP in the FA trials was larger than No-go and smaller than Go, suggesting an erroneous processing at the stimulus-response mapping level: because this stage triggers the response execution, we concluded that the neural processes underlying the pP were mainly responsible for the subsequent error commission. Finally, sLORETA source analyses of the post-error potentials extended previous findings indicating, for the first time in the ERP literature, the right anterior insula as Pe generator.
•The motor error is accounted by erroneous stimulus–response mapping.•The pP component predicts the motor error 80ms before its execution.•New interpretations are provided about the modulation of the N2 component.•sLORETA indicated the right anterior insula as Pe generator.
Objective: The aim of the present study was to investigate the cortical correlates of the intraindividual coefficient of variation (ICV) in a go/no-go task, focusing on the prefrontal cortex (PFC) ...contribution and evaluating both pre- and poststimulus brain activity. Method: We recorded event-related potentials (ERPs) in 40 subjects, arranged a posteriori in 2 groups on the basis of their ICV values. By this method, we formed the consistent (low ICV; n = 20) and inconsistent (high ICV; n = 20) group: the age, speed, and accuracy performance of the 2 groups were matched. Results: The prestimulus anticipatory PFC activity, as reflected by the prefrontal negativity (pN) wave, and the poststimulus P3 component were larger in the consistent than in the inconsistent group. In contrast, no differences were observed between groups in the brain activities associated to motor preparation and early sensory processing. Conclusions: Data are interpreted as an enhanced top-down control in consistent performers, likely characterized by a greater sustained attention on the task.
The literature on aerobic exercise and neurocognition reports acute post-exercise enhancement of neural activity linked to motor preparation in the premotor area and inhibitory control in the ...frontoparietal areas. However, the acute effect of vigorous-intensity aerobic exercise (VIAE) on the prefrontal, the insular, and the occipito-parietal activities linked to proactive control, early perceptual, and attentional processing is indeterminate. Thus, the present study investigated the acute effect of VIAE on the neurobehavioral correlates of these proactive and reactive neurocognitive functions. Young, healthy subjects participated in two separate experimental sessions: 30 min of VIAE and 30 min of internet browsing. Before and immediately after the two sessions, we recorded high-resolution electroencephalograms while performing a visuomotor discriminative response task. For testing the effect of VIAE on cognitive processing, we analyzed the behavioral performance and event-related potentials (ERPs). The analysis of behavioral data did not reveal any VIAE effect on task performance. The analysis of ERPs showed no significant VIAE effect on the proactive functions in the premotor and the prefrontal areas, but significant effects on the reactive functions related to selective attention in parietal areas (indexed by the N1 amplitude) and perceptual awareness in the anterior insula (indexed by the pN1 latency). We concluded that a single bout of VIAE does not affect the proactive functions in the premotor and the prefrontal areas, but modulates the early reactive neural mechanisms underlying perceptual awareness of stimuli in the insular cortex and selective attention in the parieto-occipital areas.
•The study investigated the acute effect of Vigorous Intensity Aerobic Exercise (VIAE) on cognitive functions.•The ERP analysis shows acute VIAE effect on the reactive, but not on the proactive cognitive functions.•The neural mechanisms linked to selective visual attention and perceptual processing were affected.
The aim of this study was to describe the spectral features of pre-stimulus event-related potential (ERP) components elicited in visual tasks such as the Bereitschaftspotential (BP), prefrontal ...negativity (pN) and visual negativity (vN). ERPs are considered time-locked and phase-locked (evoked) activity, but we have also analyzed the non-phase but time-locked (induced) activity in the same interval by applying the temporal spectral evolution (TSE) method. Participants (N = 26) were tested in a passive task, a simple response task (SRT) and a discriminative response task (DRT), where EEG activity was recorded with 64 scalp electrodes. We analyzed the time-frequency modulations (phase and non-phase) prior to the onset of the stimuli in the sub-delta, delta, theta, alpha, beta, and gamma frequency bands. The results showed that all the pre-stimulus ERP components were mainly regulated by evoked activity in the sub-delta band. On the other hand, induced activity seems to be linked to evoked responses but with a different psychophysiological role. We concluded that other preparatory cognitive mechanisms associated with ERPs can also be detected by the TSE method. This finding may suggest underlying mechanisms in non-phase activity and requires the addition of non-phase activity analysis to the traditional analysis (phase and evoked activity).
Event-Related Potentials (ERPs) occurring independently from any stimulus are purely endogenous (emitted potentials) and their neural generators can be unequivocally linked with cognitive processes. ...In the present study, the subjects performed two similar visual counting tasks: a standard two-stimulus oddball, and an omitted-target oddball task, characterized by the physical absence of the target stimulus. Our investigation aimed at localizing the neural sources of the scalp-recorded endogenous/emitted ERPs. To optimize the source localization, the high temporal resolution of electrophysiology was combined with the fine spatial information provided by the simultaneous recording of functional magnetic resonance (fMRI). Both tasks identified two endogenous ERP components in the 300 to 520 ms interval. An earlier component, pP2, showed a bilateral generator in the anterior Insula. A later P3 component (P3b) was generated bilaterally in the temporal-parietal junction, the premotor and motor area and the anterior intraparietal sulcus (this latter one only in the standard oddball). Anticipatory slow waves (beginning 900 to 500 ms pre-stimulus), also of endogenous nature, were produced by the inferior and middle frontal gyrus and the supplementary and cingulate motor areas. Our protocol disentangled pre- from post-stimulus fMRI activations and provided original clues to the psychophysiological interpretation of emitted/endogenous ERPs.
The existence of neural correlates of spatial attention is not limited to the reactive stage of stimulus processing: neural activities subtending spatial attention are deployed well ahead of stimulus ...onset. ERP evidence supporting this proactive (top-down) attentional control is based on trial-by-trial S1–S2 paradigms, where the onset of a directional cue (S1) indicates on which side attention must be directed to respond to an upcoming target stimulus (S2). Crucially, S1 onset trigger both attention and motor preparation, therefore, these paradigms are not ideal to demonstrate the effect of attention at preparatory stage of processing. To isolate top-down anticipatory attention, the present study used a sustained attention paradigm based on a steady cue that indicates the attended side constantly throughout an entire block of trials, without any onset of an attentional cue. The main result consists in the description of the attention effect on the visual negativity (vN) component, a growing neural activity starting before stimulus presentation in extrastriate visual areas. The vN was consistently lateralized in the hemisphere contralateral to the attended side, regardless of the hand to be used. At the opposite, the lateralized motor activity emerged long after, confirming that the hand-selection process followed the spatial attention orientation process. The present study confirms the anticipatory nature of the vN component and corroborate its role in terms of preparatory visuospatial attention.
ERPs occurring independently of any specific sensory event are purely endogenous (emitted potentials) and their neural generators univocally linked with cognitive components. Aim of the study was to ...localize and compare the sources of the scalp-recorded ERPs from two visual tasks: a standard two-stimulus oddball and an omitted-target oddball task, combining the high temporal resolution of electrophysiology with the fine spatial information provided by fMRI.
Thirteen healthy right-handed volunteers (5 females; mean age 26 years, range 22–29), were enrolled. The source modelling (dipole analysis) of ERPs was seeded to the clusters of fMRI activations. The simultaneous EEG-fMRI recording guaranteed the same cognitive states during the experimental session.
Data depicted an antero-to-posterior neural circuitry for the rare, task–relevant events. P300 (P3b) was generated in frontal, temporo-parietal and parietal areas (these latter only in the standard oddball), namely the temporo-parietal junction (TPj), the premotor and motor area (M1) and the anterior intraparietal sulcus (aIPs). Anterior Insula contributed to the pP2, a recently described prefrontal component (different from the P3a) associated with the stimulus–response mapping. The anticipatory prefrontal negativity (pN) and Bereitschaftspotential (BP) were produced by anterior areas, namely the inferior and middle frontal gyrus over the lateral brain surface and the SMA-CMA areas over the medial cortex.
Recording emitted ERPs from omission of target stimuli in a simultaneous EEG-fMRI event-related paradigm allows a detailed spatio-temporal modeling of the neural generators of purely endogenous late potentials and provide useful insight to the interpretation of emitted/endogenous ERPs.
Emotional perception has been extensively studied, but only a few studies have investigated the brain activity preceding exposure to emotional stimuli, especially when they are triggered by the ...subject himself. Here, we sought to investigate the emotional expectancy by means of movement related cortical potentials (MRCPs) in a self-paced task, in which the subjects begin the affective experience by pressing a key. In this experiment, participants had to alternatively press two keys to concomitantly display positive, negative, neutral, and scrambled images extracted from the International Affective Pictures System (IAPS). Each key press corresponded to a specific emotional category, and the experimenter communicated the coupling before each trial so that the subjects always knew the valence of the forthcoming picture. The main results of the present study included a bilateral positive activity in prefrontal areas during expectancy of more arousing pictures (positive and negative) and an early and sustained positivity over occipital areas, especially during negative expectancy. In addition, we observed more pronounced and anteriorly distributed Late Positive Potential (LPPs) components in the emotional conditions. In conclusion, these results show that emotional expectancy can influence brain activity in both motor preparation and stimulus perception, suggesting enhanced pre-processing in the to-be-stimulated areas. We propose that before a predictable emotional stimulus, both appetitive and defensive motivational systems act to facilitate the forthcoming processing of survival-relevant contents by means of an enhancement of attention toward more arousing pictures.
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