Neural correlates of the eye dominance effect in human face perception: the left-visual-field superiority for faces revisited.

Faces are processed best when they are presented in the left visual field (LVF), a phenomenon known as LVF superiority. Although one eye contributes more when perceiving faces, it is unclear how the dominant eye (DE), the eye we unconsciously use when performing a monocular task, affects face processing. Here, we examined the influence of the DE on the LVF superiority for faces using event-related potentials. Twenty left-eye-dominant (LDE group) and 23 right-eye-dominant (RDE group) participants performed the experiments. Face stimuli were randomly presented in the LVF or right visual field (RVF). The RDE group exhibited significantly larger N170 amplitudes compared with the LDE group. Faces presented in the LVF elicited N170 amplitudes that were significantly more negative in the RDE group than they were in the LDE group, whereas the amplitudes elicited by stimuli presented in the RVF were equivalent between the groups. The LVF superiority was maintained in the RDE group but not in the LDE group. Our results provide the first neural evidence of the DE's effects on the LVF superiority for faces. We propose that the RDE may be more biologically specialized for face processing.

Event-related Potential Patterns Reflect Reversed Hemispheric Activity during Visual Attention Processing in Children with Dyslexia: A Preliminary Study.

OBJECTIVE: Individuals with dyslexia experience reading difficulties, whereas their other cognitive abilities seem normal. The purpose of this study was to investigate the event-related potential (ERP) patterns of children with dyslexia during a target-detection task. METHODS: Seventeen children with dyslexia and 18 children without this disorder participated in this study. We evaluated their writing and reading ability, symptoms of attention-deficit/hyperactivity disorder, and intelligence quotient. ERPs were recorded while participants performed a target-detection task, and the peak amplitude and latency of P100 and P300 were analyzed. The lateral asymmetry index (LAI) was calculated for each ERP component. RESULTS: The dyslexic group exhibited longer reaction times and larger P100 amplitudes than the non-dyslexic group in the right hemisphere. The P100 latency was also significantly delayed in the right hemisphere of those in the dyslexic group compared with those in the non-dyslexic group. The P300 amplitude was larger in the right hemisphere compared with left hemisphere in the dyslexic group, whereas no interhemispheric differences were observed with respect to the P300 latency. The LAI for P100 showed a significant right hemispheric dominance, whereas the LAI for P100 was significantly correlated with the accuracy of target detection in children with dyslexia. CONCLUSION: Our results suggest that right hemispheric dominance acts as an ancillary system that compensates for poor reading in children with dyslexia.

Quantitative Electroencephalography Reflects Inattention, Visual Error Responses, and Reaction Times in Male Patients with Attention Deficit Hyperactivity Disorder.

OBJECTIVE: Quantitative electroencephalography (qEEG) has been increasingly used to evaluate patients with attention deficit hyperactivity disorder (ADHD). The aim of this study was to assess the correlation between qEEG data and symptom severity in patients with ADHD. METHODS: Fifteen patients with ADHD and 20 healthy controls (HCs) were recruited. Electroencephalography was assessed in the resting-state, and qEEG data were obtained in the eyes-closed state. The Korean version of the ADHD Rating Scale (K-ARS) and continuous performance tests (CPTs) were used to assess all participants. RESULTS: Theta-band (4-7 Hz) power across the brain was significantly positively correlated with inattention scores on the K-ARS, reaction times and commission errors on the CPTs in ADHD patients. Gamma-band (31-50 Hz) power was significantly positively correlated with the results of the auditory CPTs in ADHD patients. The theta/alpha (8-12 Hz) and theta/beta (13-30 Hz) ratios were significantly negatively correlated with commission and omission errors on auditory CPTs in ADHD patients. No significant correlations between qEEG relative power and K-ARS and CPT scores were observed in HCs. CONCLUSION: Our results suggest that qEEG may be a useful adjunctive tool in patients with ADHD.