An Underestimation Bias in the Numerical Perception of Rewarding Stimuli: An ERP Study.

ERP studies have associated posttraumatic stress disorder (PTSD) with enhanced P3 amplitudes in response to trauma-related stimuli, along with reduced amplitudes in the context of neutral (trauma-unrelated) stimuli. Additionally, a bias toward trauma-related stimuli is also observed among trauma-exposed participants not meeting criteria for PTSD, suggesting that trauma exposure itself, and not only the severity of posttraumatic stress (PTS), is a critical factor in information processing changes. However, previous examination of the response of trauma-exposed (PTSD and non-PTSD) participants to novel, neutral stimuli has produced conflicting findings. The current study examined ERPs in response to a novelty oddball paradigm comprised of neutral distractor sounds. Participants were 16 individuals with PTSD, 21 trauma-exposed individuals without PTSD, and 12 nontraumatized controls. Detailed trauma histories and PTS symptoms were collected. A significant effect of group on early ERPs was observed, showing an increase in the N1-P2 complex peak amplitude among the PTSD group, relative to controls. Among the entire sample, significant positive correlations were observed between PTS symptom severity, as well as trauma history, and early N1-P2 complex peak amplitudes, in response to novel stimuli. Furthermore, trauma-exposed participants with no PTS symptoms exhibited larger N1 amplitudes compared to participants with no trauma history. No trauma-related alterations in later ERP components were observed. These results suggest that trauma exposure may lead to hyperarousal at early processing levels, even in response to neutral novel stimuli. The findings concur with the neurocircuitry model that associates PTSD with hyperresponsivity of the amygdala.

Brain Response to Visceral Aversive Conditioning: A Functional Magnetic Resonance Imaging Study

Multiple-cue probabilistic learning in spider-fearful and in panic-prone individuals

Non‐verbal number sense has been shown to significantly correlate with arithmetic fluency. Accumulated behavioral evidence indicates that the cognitive mechanism relies on visual perception. However, few studies have investigated the neural mechanism underlying this association. Following the visual perception account, we hypothesized that there would be a neural association in occipital areas of the brain between non‐verbal number sense, arithmetic fluency, and visual perception. We analyzed event‐related potentials that are sensitive to neural responses while participants performed five cognitive tasks: simple addition, simple subtraction, numerosity comparison, figure matching, and character rhyming. The single‐trial ERP‐behavior correlation approach was used to enhance the statistical power. The results showed that the N1 component significantly correlated with reaction time at occipital electrodes on all tasks except for character rhyming. The N1 component for arithmetic fluency (simple addition and subtraction) and character rhyming correlated with the reaction time for numerosity comparison and figure matching. The results suggest that there are neural associations between arithmetic fluency, non‐verbal number sense, and visual perception in the occipital cortex, and that visual perception is the shared mechanism for both non‐verbal number sense and arithmetic fluency.

To explore whether the use of personally relevant stimuli, for some tasks in the Coma Recovery Scale - Revised (CRS-R), generates more responses in patients with prolonged disorders of consciousness compared with neutral stimuli. Multiple single-case design. Three patients with prolonged disorders of consciousness recruited from an inpatient department at a regional brain injury rehabilitation clinic in Stockholm, Sweden. Patients were repeatedly assessed with the CRS-R. Randomization tests (bootstrapping) were used to compare the number of responses generated by personally relevant and neutral stimuli on 5 items in the CRS-R. Compared with neutral stimuli, photographs of relatives generated significantly more visual fixations. A mirror generated visual pursuit to a significantly greater extent than other self-relevant stimuli. On other items, no significant differences between neutral and personally relevant stimuli were seen. Personally relevant visual stimuli may minimize the risk of missing visual fixation, compared with the neutral stimuli used in the current gold standard behavioural assessment measure (CRS-R). However, due to the single-subject design this conclusion is tentative and more research is needed.

Background Identifying predictors of developmental outcomes in non-suicidal self-injury (NSSI) is crucial and goes beyond tracking its progression. EEG technology is notable for its consistent and objective neurophysiological recordings in NSSI detection. Using ERP components in deep learning models for predicting these outcomes is still underexplored. Methods Twenty-six in the remission group (RG), twenty-nine in the aggravation group (AG), and twenty-seven in the healthy group (HG) completed the affective Stroop task with EEG. N2 and P3 component differences were analyzed across groups, and the EEGNet model was used to assess NSSI developmental outcomes. Result A significant interaction was observed between group and emotion on N2 (F (2, 79) = 16.934, p < 0.001, η2 = 0.300). Under neutral stimuli, N2 was smallest in HG, larger in RG, and largest in AG, while for negative stimuli, N2 in HG was smaller than in RG and AG. A significant group effect on P3 was noted (F (2, 79) = 7.607, p < 0.001, η2 = 0.161), with HG exhibiting larger P3 compared to RG and AG. The N2 under neutral stimuli achieved the highest classification accuracy (94.31%). Conclusion The findings indicate that NSSI is linked to cognitive processing deficits, including impaired control and resource allocation to stimuli. Additionally, N2 amplitudes were shown to reliably predict developmental outcomes in NSSI.

Previous studies have highlighted the role of the brain reward and cognitive control systems in the etiology of anorexia nervosa (AN). In an attempt to disentangle the relative contribution of these systems to the disorder, we used functional magnetic resonance imaging (fMRI) to investigate hemodynamic responses to reward-related stimuli presented both subliminally and supraliminally in acutely underweight AN patients and age-matched healthy controls (HC). fMRI data were collected from a total of 35 AN patients and 35 HC, while they passively viewed subliminally and supraliminally presented streams of food, positive social, and neutral stimuli. Activation patterns of the group × stimulation condition × stimulus type interaction were interrogated to investigate potential group differences in processing different stimulus types under the two stimulation conditions. Moreover, changes in functional connectivity were investigated using generalized psychophysiological interaction analysis. AN patients showed a generally increased response to supraliminally presented stimuli in the inferior frontal junction (IFJ), but no alterations within the reward system. Increased activation during supraliminal stimulation with food stimuli was observed in the AN group in visual regions including superior occipital gyrus and the fusiform gyrus/parahippocampal gyrus. No group difference was found with respect to the subliminal stimulation condition and functional connectivity. Increased IFJ activation in AN during supraliminal stimulation may indicate hyperactive cognitive control, which resonates with clinical presentation of excessive self-control in AN patients. Increased activation to food stimuli in visual regions may be interpreted in light of an attentional food bias in AN.

Many studies have shown that increasing the number of neutral stimuli in a display decreases distractor interference. This result has been interpreted within two different frameworks; a perceptual load account, based on a reduction in spare resources, and a dilution account, based on a degradation in distractor representation and/or an increase in crosstalk between the distractor and the neutral stimuli that contain visually similar features. In four experiments, we systematically manipulated the extent of attentional focus, stimulus category, and preknowledge of the target to examine how these factors would interact with the display set size to influence the degree of distractor processing. Display set size did not affect the degree of distractor processing in all situations. Increasing the number of neutral items decreased distractor processing only when a task induced a broad attentional focus that included the neutral stimuli, when the neutral stimuli were in the same category as the target and distractor, and when the preknowledge of the target was insufficient to guide attention to the target efficiently. These results suggest that the effect of neutral stimuli on the degree of distractor processing is more complex than previously assumed. They provide new insight into the competitive interactions between bottom-up and top-down processes that govern the efficiency of visual selective attention.

Disruption of implicit perceptual memory by intervening neutral stimuli

Emotional picture processing in children: An ERP study

Money priming enhances sensitivity to the outcome feedback of decision-making under uncertainty: Evidence from an ERP study

Abstract. Emotional signals from the face and body are normally perceived as an integrated whole in everyday life. Previous studies have revealed an incongruent effect which refers to distinctive behavioral and neural responses to emotionally congruent versus incongruent face-body compounds. However, it remains unknown which kind of the face-body compounds caused the incongruence effect. In the present study, we added neutral face and neutral body stimuli to form new face-body compounds. Forty subjects with normal or corrected-to-normal vision participated in this experiment. By comparing the face-body compounds with emotional conflict and face-body compounds with neutral stimuli, we could investigate the source of the incongruent effect. For both behavioral and event-related potential (ERP) data, a 2 (bodily expression: happiness, fear) × 2 (congruence: congruent, incongruent) repeated-measure analysis of variance (ANOVA) was performed to re-investigate the incongruent effect and a 3 (facial expression: fearful, happy, neutral) × 3 (bodily expression: fearful, happy, neutral) repeated-measure ANOVA was performed to clarify the source of the incongruent effect. As expected, both behavioral and ERP results have successfully repeated the incongruent effect. Specifically, the behavioral data showed that emotionally congruent versus incongruent face-body compounds were recognized more accurately ( p < .05). The ERP component of N2 was modulated by the emotional congruency between the facial and bodily expression showing that the emotionally incongruent compounds elicited greater N2 amplitudes than emotionally congruent compounds ( p < .05). No incongruent effect was found for P1 or P3 component ( p = .079, p = .99, respectively). Furthermore, by comparing the emotionally incongruent pairs with the neutral baseline, the present study suggests that the source of the incongruent effect might be from the happy face-fearful body compounds. We speculate that the emotion expressed by the fearful body was much more intensive than the emotion expressed by the happy body and thus caused a stronger interference in judging the facial expressions.

Chapter 17 Adaptive dopaminergic neurons report the appetitive value of environmental stimuli

Despite an initial focus on negative threatening stimuli, researchers have more recently expanded the investigation of attentional biases toward positive rewarding stimuli. The present meta-analysis systematically compared attentional bias for positive compared with neutral visual stimuli across 243 studies (N = 9,120 healthy participants) that used different types of attentional paradigms and positive stimuli. Factors were tested that, as postulated by several attentional models derived from theories of emotion, might modulate this bias. Overall, results showed a significant, albeit modest (Hedges' g = .258), attentional bias for positive as compared with neutral stimuli. Moderator analyses revealed that the magnitude of this attentional bias varied as a function of arousal and that this bias was significantly larger when the emotional stimulus was relevant to specific concerns (e.g., hunger) of the participants compared with other positive stimuli that were less relevant to the participants' concerns. Moreover, the moderator analyses showed that attentional bias for positive stimuli was larger in paradigms that measure early, rather than late, attentional processing, suggesting that attentional bias for positive stimuli occurs rapidly and involuntarily. Implications for theories of emotion and attention are discussed.

This study used in vivo microdialysis to examine the release of dopamine (DA) in the nucleus accumbens (nAc) during the performance of a previously learned, signalled sucrose reward task, and during conditioning of a neutral tone stimulus to this reward. Behavioural measures (magazine entries) confirmed that stimuli associated with sucrose presentation became secondary rewarding stimuli, and DA release was also monitored during subsequent presentation of these stimuli alone. Perhaps surprisingly, during magazine entry for consumption of sucrose, i.e. in conditions similar to routine training, dialysate DA levels in the nAc did not increase. In contrast, during conditioning of the tone with light-sucrose, dopamine levels increased consistently and significantly. Interestingly, DA levels were somewhat, but significantly, increased when tone alone was presented in a test session, i.e. two hours after conditioning, and even more so when tone was combined with the light previously associated with sucrose. In this latter case the number of magazine entries increased to a level similar to that seen during conditioning. Presentation of light alone resulted in a similar level of magazine entries to tone alone, but no significant increase in DA. In summary, these studies confirm that a neutral stimulus can acquire the behavioural properties of reward when conditioned. The neurochemical data, on the other hand, suggest that increases of DA in nAc are more likely to be related to new associative learning than to established incentive or consumatory processes. The increase in DA release in the test session may be related either to the secondary reinforcing properties acquired by the stimulus, or to the change in contingencies, or to the aversive effects of the omission of reward.