...understanding decisional processes, and reasons of decision failure, would be helpful to clarify the executive dysfunctions of clinical conditions such as obsessive compulsive disorders, ...impulsivity, and addictions (typically intended as a failure of inhibition; Chamberlain et al., 2005; Crews and Boettiger, 2009; Álvarez-Moya et al., 2011), as well as success in real-life tasks (e.g., car driving; Bunce et al., 2012) and goal-directed behaviors (e.g., complying with diet schedules; Jahanshahi et al., 2015). ...except for the motor preparation activities of the frontal areas, as reflected by the Bereitschaftspotential (BP; e.g., Shibasaki and Hallett, 2006) and the lateralized readiness potential (LRP; e.g., Rinkenauer et al., 2004), only the very recent literature started to report the ERP correlates of the PFC in the executive functioning and variability (for a review see Di Russo et al., 2017). Looking into the Frontal Lobes: Emerging Evidence on the ERP Correlates of Executive Functions When performing a decision-making task, the contribution of the PFC executive functions is manifested mainly through cognitive processes like top-down attentional control, maintenance of information in the short-term memory, ability to ignore distractors and focus on relevant features, and inhibition of the wrong schema and selection of the appropriate one. Since even one of these processes would be able to affect the inter- and intra-individual variability of the performance, they should be dissociated and investigated separately. A prefrontal activity compatible with the pN was described by West and Alain (2000) adopting a Stroop task: findings are consistent in revealing that momentary lapses of attention are associated with a pre-stimulus change in the ERP activity over the frontal regions. ...it was shown that also inter-individual variability of performance was associated with the individual level of pN activity: in other words, the more consistent performers are marked by larger pN activity than the less consistent ones (Perri et al., 2015a).
Hypnotizability refers to the individual responsiveness to hypnosis, and literature shows that the greater the hypnotizability, the more effective the hypnotic suggestions. So far, few studies ...attempted to enhance hypnotizability, and only two adopted brain stimulation with magnetic pulses. In the present study, we aimed to boost hypnotizability through transcranial direct current stimulation (tDCS). To this aim, bilateral tDCS was applied over the dorsolateral prefrontal cortex (DLPFC) with the target electrode providing negative current (cathodal stimulation) over the left hemisphere. Twenty-nine subjects participated in the study and they were randomly assigned to the sham or the active group in a double-blind design. The hypnotic experience was assessed before and after the stimulation through a phenomenological measure of consciousness (the PCI-HAP). The main findings revealed that a single tDCS session enhanced the hypnotic depth by 11% and reduced the volitional control by 30%, while no differences emerged in the sham group. This is the first study adopting the electrical neurostimulation to produce an alteration of hypnotizability and sense of agency, and confirmed the key-role of the DLPFC and executive control in the hypnotic phenomena. If confirmed, these findings could have relevant implications as enhanced hypnotizability could be translated into better outcomes for many hypnotic interventions.
The anticipation of upcoming events is a key-feature of cognition. Previous investigations on anticipatory visuospatial attention mainly adopted transient and–more rarely–sustained tasks, whose main ...difference consists in the presence of transient or sustained cue stimuli and different involvement of top-down or bottom-up forms of attention. In particular, while top-down control has been suggested to drive sustained attention, it is not clear whether both endogenous and exogenous controls are recruited in transient attention task, or whether the cue-evoked attention may be interpreted as a mainly bottom-up guided process. To solve this issue, the present study focused on the preparatory brain activity of participants performing a sustained and a transient attention task. To this aim, the focus was on pre-stimulus event-related potential (ERP) components, i.e., the prefrontal negativity (pN) and the visual negativity (vN), associated with cognitive and sensorial preparation, emerging from prefrontal and visual areas, respectively. Results indicated that the pN was specific for the sustained task, while the vN emerged for both tasks, although smaller in the transient task, with a hemispheric lateralization contralateral to the attended hemifield. The present findings support the interpretation of the vN as a modality-specific index of attentional preparation, and suggest the presence of cognitive endogenous control in sustained tasks only, as revealed by the presence of a prefrontal activity that was interpreted as the locus of the top-down attentional modulation during the stimulus expectancy stage.
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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