Enhancement of visual dominance effects at the response level in children with attention-deficit/hyperactivity disorder.

Previous studies have widely demonstrated that individuals with attention-deficit/hyperactivity disorder (ADHD) exhibit deficits in conflict control tasks. However, there is limited evidence regarding the performance of children with ADHD in cross-modal conflict processing tasks. The current study aimed to investigate whether children with ADHD have poor conflict control, which has an impact on sensory dominance effects at different levels of information processing under the influence of visual similarity. A total of 82 children aged 7 to 14 years, including 41 children with ADHD and 41 age- and sex-matched typically developing (TD) children, were recruited. We used the 2:1 mapping paradigm to separate levels of conflict, and the congruency of the audiovisual stimuli was divided into three conditions. In C trials, the target stimulus and the distractor stimulus were identical, and the bimodal stimuli corresponded to the same response keys. In PRIC trials, the distractor stimulus differed from the target stimulus and did not correspond to any response keys. In RIC trials, the distractor stimulus differed from the target stimulus, and the bimodal stimuli corresponded to different response keys. Therefore, we explicitly differentiated cross-modal conflict into a preresponse level (PRIC > C), corresponding to the encoding process, and a response level (RIC > PRIC), corresponding to the response selection process. Our results suggested that auditory distractors caused more interference during visual processing than visual distractors caused during auditory processing (i.e., typical auditory dominance) at the preresponse level regardless of group. However, visual dominance effects were observed in the ADHD group, whereas no visual dominance effects were observed in the TD group at the response level. A possible explanation is that the increased interference effects due to visual similarity and children with ADHD made it more difficult to control conflict when simultaneously confronted with incongruent visual and auditory inputs. The current study highlights how children with ADHD process cross-modal conflicts at multiple levels of information processing, thereby shedding light on the mechanisms underlying ADHD.

Cross-modal conflict deficit in children with attention-deficit/hyperactivity disorder.

The difference between the audiovisual incongruent condition and the audiovisual congruent condition is known as cross-modal conflict, which is an important behavioral index to measure the conflict control function. Previous studies have found conflict control deficits in children with attention-deficit/hyperactivity disorder (ADHD), but it is not clear whether and how cross-modal conflict occurs in children with ADHD at different processing levels. The current study adopted the cross-modal matching paradigm to recruit 25 children with ADHD (19 boys and 6 girls) and 24 TD children (17 boys and 7 girls), aiming to investigate the cross-modal conflict effect at the perception and response levels of children with ADHD. The results showed that both groups of children showed significant cross-modal conflict, and there was no significant difference between the ADHD and TD groups in the number of error trials and mean response time. However, the cross-modal conflict effect caused by auditory distractors was different between the ADHD and TD groups; the TD group had stronger auditory conflict at the response level, whereas the ADHD group had weaker auditory conflict. This indicates that the ADHD group had a deficit of auditory conflict at the response level.

Effect of Audiovisual Cross-Modal Conflict during Working Memory Tasks: A Near-Infrared Spectroscopy Study.

Cognitive conflict effects are well characterized within unimodality. However, little is known about cross-modal conflicts and their neural bases. This study characterizes the two types of visual and auditory cross-modal conflicts through working memory tasks and brain activities. The participants consisted of 31 healthy, right-handed, young male adults. The Paced Auditory Serial Addition Test (PASAT) and the Paced Visual Serial Addition Test (PVSAT) were performed under distractor and no distractor conditions. Distractor conditions comprised two conditions in which either the PASAT or PVSAT was the target task, and the other was used as a distractor stimulus. Additionally, oxygenated hemoglobin (Oxy-Hb) concentration changes in the frontoparietal regions were measured during tasks. The results showed significantly lower PASAT performance under distractor conditions than under no distractor conditions, but not in the PVSAT. Oxy-Hb changes in the bilateral ventrolateral prefrontal cortex (VLPFC) and inferior parietal cortex (IPC) significantly increased in the PASAT with distractor compared with no distractor conditions, but not in the PVSAT. Furthermore, there were significant positive correlations between Δtask performance accuracy and ΔOxy-Hb in the bilateral IPC only in the PASAT. Visual cross-modal conflict significantly impairs auditory task performance, and bilateral VLPFC and IPC are key regions in inhibiting visual cross-modal distractors.

The Tactile-Visual Conflict Processing and Its Modulation by Tactile-Induced Emotional States: An Event-Related Potential Study.

This experiment used event-related potentials (ERPs) to study the tactile-visual information conflict processing in a tactile-visual pairing task and its modulation by tactile-induced emotional states. Eighteen participants were asked to indicate whether the tactile sensation on their body matched or did not match the expected tactile sensation associated with the object depicted in an image. The type of tactile-visual stimuli (matched vs. mismatched) and the valence of tactile-induced emotional states (positive vs. negative) were manipulated following a 2 × 2 factorial design. Electrophysiological analyses revealed a mismatched minus matched negative difference component between 420 and 620 ms after stimulus onset in the negative tactile-induced emotional state condition. This ND420-620 component was considered as a sign of the cross-modal conflict processing during the processing of incongruent tactile-visual information. In contrast, no significant mismatched minus matched negative difference component was found in the positive tactile-induced emotional state condition. Together, these results support the hypothesis that a positive emotional state induced by a positive tactile stimulation improves tactile-visual conflict processing abilities.

Reward enhances cross-modal conflict control in object categorization: Electrophysiological evidence.

Cross-modal conflict arises when information from different sensory modalities are incompatible with each other. Such conflict may influence the processing of stimuli in the task-relevant modality and call for cognitive control to resolve this conflict. Here, we investigate how reward modulates cross-modal conflict control during object categorization. Participants categorized pictures as representing animate or inanimate objects while ignoring auditory stimuli. We manipulated the audiovisual congruency and performance-dependent reward (reward vs. no-reward). Behavioral results showed a significant cross-modal interference effect only in the no-reward condition, not in the reward condition. Neurally, we found that the frontocentral N2and theta band oscillations were larger in the incongruent condition than in the congruent condition, but only when there was no reward for performance. The converging behavioral and electrophysiological evidence demonstrates that reward enhances cognitive control in a cross-modal context and reduces cross-modal conflict.