Ruth

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Processing biological gender and number information during Chinese pronoun resolution: ERP evidence for functional differentiation

There have been a number of behavioral and neural studies on the processing of syntactic gender and number agreement information, marked by different morpho-syntactic features during sentence comprehension. By using the event-related potential (ERP) technique, the present study investigated whether the processing of semantic gender information and the processing of notional number information can be differentiated and to what extent they might interact during Chinese pronoun resolution. The pronoun (with singular form in Experiment 1 and with plural form in Experiment 2) in a sentence matched its antecedent or mismatched it with respect to either biological gender or notional number or both. While the number mismatch elicited a P600 effect starting from 550 ms (for singular pronoun) or 400 ms (for plural pronoun) post-onset of the pronoun, the gender mismatch elicited an earlier (for singular) and larger (for both singular and plural) P600 effect. More importantly, the double mismatch produced a P600 effect identical to the effect elicited by the single gender mismatch. These results demonstrate that biological gender information and notional number information are processed differentially and have different processing priorities during Chinese pronoun resolution.     

When does the brain distinguish between genuine and ambiguous smiles? An ERP study

Event-related brain potentials (ERPs) were recorded to assess the processing time course of ambiguous facial expressions with a smiling mouth but neutral, fearful, or angry eyes, in comparison with genuinely happy faces (a smile and happy eyes) and non-happy faces (neutral, fearful, or angry mouth and eyes). Participants judged whether the faces looked truly happy or not. Electroencephalographic recordings were made from 64 scalp electrodes to generate ERPs. The neural activation patterns showed early P200 sensitivity (differences between negative and positive or neutral expressions) and EPN sensitivity (differences between positive and neutral expressions) to emotional valence. In contrast, sensitivity to ambiguity (differences between genuine and ambiguous expressions) emerged only in later LPP components. Discrimination of emotional vs. neutral affect occurs between 180 and 430 ms from stimulus onset, whereas the detection and resolution of ambiguity takes place between 470 and 720 ms. In addition, while blended expressions involving a smile with angry eyes can be identified as not happy in the P200 (175–240 ms) component, smiles with fearful or neutral eyes produce the same ERP pattern as genuinely happy faces, thus revealing poor discrimination.     

Corticospinal excitability during the observation of social behavior

Evidence suggests that the observation of an action induces in the observers an enhancement of motor evoked potentials (MEPs) recorded by the observer’s muscles corresponding to those involved in the observed action. Although this is a well-studied phenomenon, it remains still unclear how the viewer’s motor facilitation is influenced by the social content characterizing the observed scene. In the present study we investigated the facilitation of the corticospinal system during the observation of either an action that does not imply a social interaction (i.e., an actor throwing a ball against a wall), or an action which implies a social interaction (i.e., an actor passing a ball to a partner). Results indicate that MEPs amplitude is enhanced during the observation of a social rather than an individual action. We contend that the increase in MEPs activation might reflect an enhancement of the simulative activity stemming from the mirror system during the observation of social interactions. Altogether these findings show that the human corticospinal system is sensitive to social interactions and may support the role of the mirror neurons system in social cognition.     

Impact of intention on the ERP correlates of face recognition

The present study investigated the impact of study-test similarity on face recognition by manipulating, in the same experiment, the expression change (same vs. different) and the task-processing context (inclusion vs. exclusion instructions) as within-subject variables. Consistent with the dual-process framework, the present results showed that participants performed better on the inclusion task than on the exclusion task, with no response bias. A mid-frontal FN400 old/new effect and a parietal old/new effect were found in both tasks. However, modulations of the ERP old/new effects generated by the expression change on recognized faces differed across tasks. The modulations of the ERP old/new effects were proportional to the degree of matching between the study face and the recognition face in the inclusion task, but not in the exclusion task. The observed modulation of the FN400 old/new effect by the task instructions when familiarity and conceptual priming were kept constant indicates that these early ERP correlates of recognition depend on voluntary task-related control. The present results question the idea that FN400 reflects implicit memory processes such as conceptual priming and show that the extent to which the FN400 discriminates between conditions depends on the retrieval orientation at test. They are discussed in relation to recent controversies about the ERP correlates of familiarity in face recognition. This study suggests that while both conceptual and perceptual information can contribute to the familiarity signal reflected by the FN400 effect, their relative contributions vary with the task demands.     

Musical experts recruit action-related neural structures in harmonic anomaly detection: Evidence for embodied cognition in expertise

Humans are extremely good at detecting anomalies in sensory input. For example, while listening to a piece of Western-style music, an anomalous key change or an out-of-key pitch is readily apparent, even to the non-musician. In this paper we investigate differences between musical experts and non-experts during musical anomaly detection. Specifically, we analyzed the electroencephalograms (EEG) of five expert cello players and five non-musicians while they listened to excerpts of J.S. Bach’s Prelude from Cello Suite No. 1. All subjects were familiar with the piece, though experts also had extensive experience playing the piece. Subjects were told that anomalous musical events (AMEs) could occur at random within the excerpts of the piece and were told to report the number of AMEs after each excerpt. Furthermore, subjects were instructed to remain still while listening to the excerpts and their lack of movement was verified via visual and EEG monitoring. Experts had significantly better behavioral performance (i.e. correctly reporting AME counts) than non-experts, though both groups had mean accuracies greater than 80%. These group differences were also reflected in the EEG correlates of key-change detection post-stimulus, with experts showing more significant, greater magnitude, longer periods of, and earlier peaks in condition-discriminating EEG activity than novices. Using the timing of the maximum discriminating neural correlates, we performed source reconstruction and compared significant differences between cellists and non-musicians. We found significant differences that included a slightly right lateralized motor and frontal source distribution. The right lateralized motor activation is consistent with the cortical representation of the left hand – i.e. the hand a cellist would use, while playing, to generate the anomalous key-changes. In general, these results suggest that sensory anomalies detected by experts may in fact be partially a result of an embodied cognition, with a model of the action for generating the anomaly playing a role in its detection.     

Proactive and reactive sequential effects on selective attention

Sequences of events can affect selective attention either through proactive mechanisms, through reactive mechanisms, or through a combination of the two. The current study examined electrophysiological responses to both prime and target stimuli in a primed dichotic listening task. Each trial presented a distractor prime syllable followed by two simultaneous syllables, and participants were asked to report one of the simultaneous syllables. Trials where the participant reported the non-primed syllable showed more negative event-related potentials at prime presentation, which may indicate inhibition of the prime representation. Trials where the participant reported the primed syllable showed more negative event-related potentials at target presentation, which may indicate cognitive conflict and effortful response selection. In context of current theories, the data suggest that the interplay of a proactive inhibition bias and a reactive potential for conflict is involved in causing sequential effects on selective attention mechanisms.     

局部表象产生中行为性别差异的神经基础

行为研究发现女性具有更好的局部表象产生能力, 但其神经基础尚不清楚。研究采用事件相关电位技术以及小世界网络分析方法, 探索局部表象产生中性别差异的大脑信息加工基础。结果显示在局部表象产生中, 女性行为反应较男性更快, 表象产生诱发的P300-650平均波幅更小, 且大脑功能网络的平均路径长度更短。深入分析发现, 反应时与脑网络的平均路径长度之间成正相关。该结果意味着低耗高效的大脑信息加工模式是女性具有更好的局部表象能力的神经基础。     

返回抑制过程中情绪面孔加工优先：ERPs研究

返回抑制(IOR)是指注意过程中个体对已搜索过的位置进行抑制, 从而在随后该位置上出现目标时发生注意重新定向或反应变慢的过程。本研究使用ERPs技术, 采用线索-靶子范式, 考察了情绪目标辨别任务中IOR的发生过程及二者的神经机制。结果发现, 与无效线索相比, 有效线索下的P1波幅更小, N1波幅更大, 正性、负性面孔N170的波幅比中性面孔大。表明当要求被试做情绪辨别任务时, IOR与对情绪信息的反应之间发生了分离, 表现出情绪加工的优先。这说明IOR和情绪偏向是发生在两种不同神经通路上的适应机制, 也为进一步探究注意与情绪的关系问题提供了来自神经电生理学的证据。