Sustained visuospatial attention enhances lateralized anticipatory ERP activity in sensory areas

Modality predictability modulation confirms the sensorial readiness function of the pre-stimulus activity in sensory brain areas

The auditory Positivity (aP) and the visual Negativity (vN) are recently discovered modality-specific event-related potential (ERP) components associated with sensory readiness, which seems promising to study anticipatory perception and attention. However, a crucial aspect of these waves remains to be determined since it is still unclear if these components are indeed related to sensory readiness or represent the result of stimulus predictably. Indeed, earlier studies found these components in tasks where stimuli were repeatedly presented uniquely in the same sensory modality. To disentangle this issue, we used an experimental design consisting of three passive tasks: a unimodal auditory condition, a unimodal visual condition, and an intermodal condition in which the visual and auditory stimuli were unpredictably alternated. Then, we compared the amplitudes of the aP and vN in the three conditions and performed correlation analyses between pre-stimulus and post-stimulus components. Crucially, results showed that in the intermodal condition the components still occur, but their amplitudes are decreased compared to unimodal condition, providing evidence that they are only partially dependent on the task and that expectancy might modulate them. This result is in line with the "modality-shift effect" costs phenomenon which can occur also for passive tasks even before stimulus presentation. In addition, the amplitude of the post-stimulus components correlated with pre-stimulus ERP. Collectively, the present study confirms that the aP and the vN reflect sensory readiness processes that "boost" post-stimulus auditory N1 and visual P1 components.

The Dominance of Anticipatory Prefrontal Activity in Uncued Sensory-Motor Tasks

Anticipatory event-related potentials (ERPs) precede upcoming events such as stimuli or actions. These ERPs are usually obtained in cued sensory-motor tasks employing a warning stimulus that precedes a probe stimulus as in the contingent negative variation (CNV) paradigms. The CNV wave has been widely studied, from clinical to brain-computer interface (BCI) applications, and has been shown to emerge in medial frontoparietal areas, localized in the cingulate and supplementary motor areas. Several dated studies also suggest the existence of a prefrontal CNV, although this component was not confirmed by later studies due to the contamination of ocular artifacts. Another lesser-known anticipatory ERP is the prefrontal negativity (pN) that precedes the uncued probe stimuli in discriminative response tasks and has been localized in the inferior frontal gyrus. This study aimed to characterize the pN by comparing it with the CNV in cued and uncued tasks and test if the pN could be associated with event preparation, temporal preparation, or both. To achieve these aims, high-density electroencephalographic recording and advanced ERP analysis controlling for ocular activity were obtained in 25 volunteers who performed 4 different visuomotor tasks. Our results showed that the pN amplitude was largest in the condition requiring both time and event preparation, medium in the condition requiring event preparation only, and smallest in the condition requiring temporal preparation only. We concluded that the prefrontal CNV could be associated with the pN, and this activity emerges in complex tasks requiring the anticipation of both the category and timing of the upcoming stimulus. The proposed method can be useful in BCI studies investigating the endogenous neural signatures triggered by different sensorimotor paradigms.

Effect of the side of presentation in the visual field on phase-locked and nonphase-locked alpha and gamma responses

Recent studies have suggested that nonphase-locked activity can reveal cognitive mechanisms that cannot be observed in phase-locked activity. In fact, we describe a concomitant decrease in nonphase-locked alpha activity (desynchronization) when stimuli were processed (alpha phase-locked modulation). This desynchronization may represent a reduction in "background activity" in the visual cortex that facilitates stimulus processing. Alternatively, nonphase-locked gamma activity has been hypothesized to be an index of shifts in attentional focus. In this study, our main aim was to confirm these potential roles for nonphase-locked alpha and gamma activities with a lateralized Go/NoGo paradigm. The results showed that nonphase-locked alpha modulation is bilaterally represented in the scalp compared to the contralateral distribution of the phase-locked response. This finding suggests that the decrease in background activity is not limited to neural areas directly involved in the visual processing of stimuli. Additionally, gamma activity showed a higher desynchronization of nonphase-locked activity in the ipsilateral hemisphere, where the phase-locked activity reached the minimum amplitude. This finding suggests that the possible functions of nonphase-locked gamma activity extend beyond shifts in attentional focus and could represent an attentional filter reducing the gamma representation in the visual area irrelevant to the task.

Does sport type matter? The effect of sport discipline on cognitive control strategies in preadolescents

This study aimed to test the effects of specific sport practices on cognitive sensory-motor performance and underlying brain functions in children. Behavioral performance and event-related potentials (ERP) were investigated during a cognitive visuomotor task in 64 preadolescent children practicing racket (Rack) sports, martial arts (Mart), indoor climbing (Clim), or not practicing any sport (controls, Cont). At the behavioral level, response speed and accuracy were studied. At the electrophysiological level, motor, cognitive and sensory-attentional readiness, and post-perceptual attentional functions were investigated. Behavioral results showed that Mart players had the fastest response time (RT). Rack players had the most consistent RT and committed the lowest omission errors. Clim athletes were the most accurate in terms of false alarms. ERP results showed that motor readiness was largest in Mart players. The Rack group had the largest cognitive preparation and the Clim one had the largest sensory-attentional readiness activity. Rack and Mart players had the largest activity associated with post-perceptual attentional processing. This result shows that practicing specific sports may allow differential benefits on cognitive processing. Racket sports seem to stimulate action speed consistency and improve accuracy for omissions, increasing cognitive preparation, and post-perceptual attentional processing. Mart practice may allow a more speed-oriented response behavior, probably due to large motor preparation and allocation of post-perceptual attentional resources, but only when response execution is required. Indoor climbing may favor response accuracy reducing unwanted responses as indexed by an increased sensory-attentional readiness. Overall, all the considered sports disciplines may improve cognitive processing, but each one is associated with different benefits on cognitive performance by possibly stimulating separate brain processing. This kind of information could be crucial to select the more appropriate sport depending on individual demands.

Neural Basis of Anticipatory Multisensory Integration

The brain is able to gather different sensory information to enhance salient event perception, thus yielding a unified perceptual experience of multisensory events. Multisensory integration has been widely studied, and the literature supports the hypothesis that it can occur across various stages of stimulus processing, including both bottom-up and top-down control. However, evidence on anticipatory multisensory integration occurring in the fore period preceding the presentation of the expected stimulus in passive tasks, is missing. By means of event-related potentials (ERPs), it has been recently proposed that visual and auditory unimodal stimulations are preceded by sensory-specific readiness activities. Accordingly, in the present study, we tested the occurrence of multisensory integration in the endogenous anticipatory phase of sensory processing, combining visual and auditory stimuli during unimodal and multimodal passive ERP paradigms. Results showed that the modality-specific pre-stimulus ERP components (i.e., the auditory positivity -aP- and the visual negativity -vN-) started earlier and were larger in the multimodal stimulation compared with the sum of the ERPs elicited by the unimodal stimulations. The same amplitude effect was also present for the early auditory N1 and visual P1 components. This anticipatory multisensory effect seems to influence stimulus processing, boosting the magnitude of early stimulus processing. This paves the way for new perspectives on the neural basis of multisensory integration.

Deficits in Early Sensory and Cognitive Processing Are Related to Phase and Nonphase EEG Activity in Multiple Sclerosis Patients

Currently, there is scarce knowledge about the relation between spectral bands modulations and the basis of cognitive impairment in multiple sclerosis (MS). In this sense, analyzing the evoked or phase activity can confirm results from traditional event-related potential (ERP) studies. However, studying the induced or nonphase activity may be necessary to elucidate hidden compensatory or affected cognitive mechanisms. In this study, 30 remitting-relapsing multiple sclerosis patients and 30 healthy controls (HCs) matched in sociodemographic variables performed a visual oddball task. The main goal was to analyze phase and nonphase alpha and gamma bands by applying temporal spectral evolution (TSE) and its potential relation with cognitive impairment in these patients. The behavioural results showed slower reaction time and poorer accuracy in MS patients compared to controls. In contrast, the time-frequency analysis of electroencephalography (EEG) revealed a delay in latency and lower amplitude in MS patients in evoked and induced alpha compared to controls. With respect to the gamma band, there were no differences between the groups. In summary, MS patients showed deficits in early sensorial (evoked alpha activity) and cognitive processing (induced alpha activity in longer latencies), whereas the induced gamma band supported the hypothesis of its role in translation of attentional focus (induced activity) and did not show strong activity in this paradigm (visual oddball).