Jiajin Yuan

Gender differences in behavioral inhibitory control: ERP evidence from a two-choice oddball task

The inhibition of inappropriate behaviors is important for adaptive living in changing environments. The present study investigated gender-related behavioral inhibitory control by recording event-related potentials for standard and deviant stimuli while subjects performed a standard/deviant distinction task by accurately pressing different keys within 1000 ms. The results showed faster reaction times (RTs) for deviant stimuli in women than in men, although RTs for standard stimuli were similar across genders. There were significant gender and stimulus interaction effects on mean amplitudes during each of the 170-230-ms, 250-330-ms, and 350-600-ms intervals, and women exhibited shorter latencies and larger amplitudes than men at deviant-related P2, N2, and P3 components. As an accurate, fast response to the rare deviant stimuli involves behavioral inhibitory control on the prepotent response whereas the response to the standard stimuli does not, it is clear that there is a general gender difference in behavioral control for human adults. This may relate to differential inhibitory demands by each gender during evolution.

The timing of cognitive control in partially incongruent categorization

We designed a novel task, partially incongruent categorization (PIC), to examine the timing of cognitive control. In the PIC task, participants categorized the probe stimulus according to a specific concept, and the number of features corresponding to the concept was varied. When there was one feature (c1 condition), the probe would elicit only categorization, but when there was more than one feature (c2 and c3 conditions), the probe would also elicit cognitive control. Here, the high temporal resolution of event‐related potentials (ERPs) was utilized to investigate the temporal patterns of activity during conflict detection and control. Cognitive control elicited a N2 that was much larger in response to c2 and c3 than c1 in stimulus‐locked waveforms, and no difference was evident between c2 and c3. The N2 was followed by a P3 that was much less on c2 and c3 than c1 trials, with no difference between c2 and c3. A dipole source analysis for two difference waves, c2−c1 and c3−c1, further showed that the corresponding dipoles of the N2 and P3 in the cognitive control conditions were in the anterior cingulate cortex (ACC) and prefrontal cortex (PFC), respectively. Taken together, the present findings support that ERP components in response to the PIC task reflect the time course of cognitive control: the N2 responds to conflict information and subsequently activates the P3 to control this conflict. The connection between the ACC and PFC is supported by their sequential activation within trials. Hum Brain Mapp, 2008.

The temporal features of self-referential processing evoked by chinese handwriting

To explore the temporal features and underlying brain structures of self-referential processing, participants were shown examples of Chinese handwriting, half of which were their own and the other half belonged to others, and asked to judge whether the handwriting was their own. In Experiment 1, the task was to categorize the handwriting by pressing the correct key as quickly as possible. In Experiment 2, after the participants recognized the stimuli, they were required to gaze at the handwriting for 3000 msec before making a response rather than responding immediately after stimulus onset. The results showed prominent differences in event-related potentials elicited by own and other handwriting conditions in the 200500 msec and 10002000 msec time windows. Dipole analyses of the difference waves, own minus other, were conducted in both of these time windows. There were two dipoles in the 200500 msec time window localized to the medial-temporal lobe and the anterior cingulate cortex (ACC), and MTL activation preceded ACC activation. Only one dipole at the posterior cingulate cortex was fitted to the 10002000 msec time window. These structures were activated sequentially in a temporal course, which provides evidence that the cortex middle structures potentially form a specific self-related processing unit, which is involved in processing various aspects of the self.

Electrophysiological correlates of category induction: PSW amplitude as an index of identifying shared attributes.

Event-related potentials (ERPs) were recorded from 15 healthy adults while they performed a category induction task. Two geometric figures characterized by three dimensions (color, shape, and stripe orientation) were presented simultaneously to subjects who were asked to identify their shared attributes. Pairs of figures sharing common attributes composed the category induction condition and pairs of identical figures composed the non-induction condition. It was hypothesized that non-induction only involves abstracting shared attributes from one stimulus, but category induction involves identifying shared attributes by comparing the two stimuli. The ERP waves elicited by induction and non-induction did not differ on N1, P2 and P3b components, but larger frontal N2 and smaller central-parietal PSW components were elicited by category induction. These results suggest that the processing of category induction is reflected in the PSW 400-650 ms post-stimulus.

Auditory-induced emotion modulates processes of response inhibition: an event-related potential study

This study investigated the impact of auditory-induced emotion on response inhibition. Fifty kinds of positive, neutral, and negative sounds were used as emotional materials whose presentation was followed by a Go/Nogo task. Event-related potentials were recorded for Go and Nogo tones. The response times for Go stimuli were longer under negative than under positive and neutral emotions. In addition, Go and Nogo stimuli elicited larger N1 amplitudes during neutral than during emotional conditions. Moreover, Nogo-related N2 was larger for neutral sounds than for positive and negative sounds. The Nogo-N2, however, was not different between positive and negative sounds. Therefore, auditory-induced emotions significantly modulated the behavioral performance and the process of response conflict monitoring, a central component to the activity of response inhibition.

THE VALENCE STRENGTH OF NEGATIVE STIMULI MODULATES VISUAL NOVELTY PROCESSING: ELECTROPHYSIOLOGICAL EVIDENCE FROM AN EVENT-RELATED POTENTIAL STUDY

In natural settings, the occurrence of unpredictable infrequent events is often associated with emotional reactions in the brain. Previous research suggested a special sensitivity of the brain to valence differences in emotionally negative stimuli. Thus, the present study hypothesizes that valence changes in infrequent negative stimuli would have differential effects on visual novelty processing. Event-related potentials (ERPs) were recorded for highly negative (HN), moderately negative (MN) and Neutral infrequent stimuli, and for the frequent standard stimulus while subjects performed a frequent/infrequent categorization task, irrespective of the emotional valence of the infrequent stimuli. The infrequent-frequent difference waves, which index visual novelty processing, displayed larger N2 amplitudes during HN condition than during MN condition which, in turn, elicited greater N2 amplitude than the Neutral condition. Similarly, in the infrequent-frequent difference waves, the frontocentral P3a and parietal LPC (late positive complex) elicited by the HN condition were more negative than those by MN stimuli, which elicited more negative amplitudes than the Neutral condition. This suggests that negative emotions of diverse strength, as induced by negative stimuli of varying valences, are clearly different in their impact on visual novelty processing. Novel stimuli of increased negativity elicited more attentional resources during the early novelty detection, and recruited increased inhibitive and evaluative processing during the later stages of response decision and reaction readiness, relative to novel stimuli of reduced negativity.

The valence strength of unpleasant emotion modulates brain processing of behavioral inhibitory control: neural correlates.

As an ability critical for adaptive social living, behavioral inhibitory control (BIC) is known to be influenced substantially by unpleasant emotion. Nevertheless, how unpleasant emotion of diverse strength influences this control, and the spatiotemporal dynamics underlying this influence, remain undetermined. For this purpose, Event-related potentials (ERPs) were recorded for standard stimulus which required no BIC, and for deviant stimuli that required controlling habitual responses, during highly unpleasant (HU), mildly unpleasant (MU) and Neutral blocks. The results showed delayed response latencies for deviant compared to standard stimuli, irrespective of emotionality. Moreover, there were significant main effects of stimulus type, and significant stimulus type and block interaction effects on the averaged amplitudes of the 230-310 ms and 330-430 ms intervals. In the deviant-standard difference waves which directly index BIC-relevant processing, these interactions were manifested by increased negative potentials as a function of the strength of unpleasant emotion across N2 and P3 components. In addition, these influences are specific to unpleasant emotion, as pleasant emotion of diverse strength produced a similar impact in the control experiment. Therefore, unpleasant emotion of diverse strength is different in impact on brain processing of behavioral inhibitory control. This impact is evident not only in early monitoring of response conflicts, but also in late processing of response inhibition.

Event-related potential correlates of the extraverts' sensitivity to valence changes in positive stimuli.

This study investigated whether the human sensitivity to valence intensity changes in positive stimuli varies with extraversion. Event-related potentials were recorded for highly positive, moderately positive, and neutral stimuli while participants (extraverts and nonextraverts) performed a standard/deviant categorization task, irrespective of the emotionality of deviants. The results of extraverts showed larger P2 and P3 amplitudes during highly positive condition than during moderately positive condition which, in turn, elicited larger P2 than neutral condition. Conversely, nonextraverts showed no differences at both P2 and P3 components. Thus, extraverts, unlike less extraverted individuals, are sensitive to valence changes in positive stimuli, which may be underlain by certain biogenetic mechanism.

Neural correlates of the belief-bias effect in syllogistic reasoning: an event-related potential study.

This study investigated electrophysiological correlates of belief-bias effects in syllogistic reasoning. Event-related brain potentials were recorded for minor premises with which participants were required to draw a logic conclusion during three conditions: the inhibitory belief condition (IBC, the belief is inhibitory to the logical task), the facilitatory belief condition (FBC, the belief is facilitatory to the logical task), and the baseline condition. The results demonstrated a more positive event-related potential deflection during IBC and FBC conditions than during the noninference baseline condition in both the 300–500 and the 1000–1600 ms time windows. Moreover, IBC elicited a more positive event-related potential deflection (P500) than did FBC across central-frontal cortical regions during the 300–600 ms interval. Therefore, this study observed a clear belief-bias effect, and the enhanced P500 activity during IBC, which relates to the belief bias that obstructs normal inferences, most likely reflects an inhibition to beliefs during later relation integration stage.

The recognition potential and rotated Chinese characters

The recognition potential (RP), which is recorded at occipital-temporal sites 200-300 ms poststimulus onset, is an event-related potential (ERP) response to a recognizable stimulus during an object recognition task. Using the rapid stream stimulation (RSS) paradigm and a word detection task, the present study investigated the effect of word detection on RP activity by manipulating angular orientation and image version of Chinese characters. The results showed larger RP amplitude during the normal condition than during the mirror-reversed condition across angular orientations. Moreover, the RP latencies were delayed for 60 degrees , 120 degrees , and 180 degrees orientations relative to the upright, and the amplitudes were larger for 0 degrees and 60 degrees orientations than for 120 degrees and 180 degrees orientations only during the normal condition. This suggests that, as mirrored by RP activity, different strategies depend on the difficulty of word recognition. More specially, piecemeal and serial processing strategy would be used when incoming information is sufficient for word recognition, whereas holistic strategy and the global analysis of categorical features would be used when a word cannot be recognized due to the degraded quality of incoming stimuli.