Dynamic cognitive processes of text-picture integration revealed by event-related potentials.

The integration of text and picture is the core of multimedia information processing. Relevant theories suggest that text and picture are processed through different channels in the early stage, and integrated in the late stage of processing. Based on these theories, the current study adopted measures of event-related potentials to examine the cognitive and neural processes of text-picture integration. The results showed that in the early stage of text-picture integration, picture processing evoked a more negative N1 over the occipital area and a N300 over the prefrontal area, which might reflect the discrimination process of visual stimuli and the imagery representation of the picture, respectively; in the late stage, the text-picture induced a N400 in the central area and an LPC over the central, parietal and temporal areas, which might be associated with the semantic activation and integration of text and picture, respectively. These results not only provide support for existing theories, but also further elucidate the dynamic neural processing of text-picture integration in terms of its temporal and spatial characteristics.

Neural correlates of cultural differences in moral decision making: a combined ERP and sLORETA study.

Cultures affect human social behaviors including moral decision making. However, the brain mechanism underlying cross-cultural moral decision making is still unclear. In the current study, the neural correlates of cultural differences in moral decision making between Chinese and westerners were investigated by combining the event-related potential technique with standardized Low-Resolution brain Electromagnetic Tomography (sLORETA) analyses. Behavioral results showed that participants made a smaller proportion of utilitarian judgments and had longer reaction times in response to personal than impersonal dilemmas, with no obvious differences between westerners and Chinese. However, the event-related potential components were significantly different between the two cultural groups. Smaller P3 amplitudes were evoked by personal than impersonal dilemmas for westerners, while for Chinese, smaller P260 deflections were elicited by personal compared with impersonal dilemmas. The current source density analysis with sLORETA revealed significantly different brain activities for P2, P3, and P260 components elicited by personal and impersonal dilemmas. Different from the sources of P2 and P3 components, which mainly localized in cingulate gyrus and medial frontal areas, the P260 component mainly activated areas in the posterior cingulate, parahippocampal gyrus, and cuneus and precuneus cortices. These findings suggest a relatively earlier initiation of the moral decision-making process for westerners and a relatively integrated processing during the solution of moral decision making for Chinese.

EEG dynamics reflects the partial and holistic effects in mental imagery generation.

Mental imagery generation is essential in the retrieval and storage of knowledge. Previous studies have indicated that the holistic properties of mental imagery generation can be evaluated more easily than the partial properties. However, the relationship between partial and holistic mental imagery generations has not been clearly demonstrated. To address this issue, we designed a task to investigate the changes in the spectrum of the electroencephalogram (EEG) during partial or holistic imagery generation. EEG signals were obtained from 18 healthy subjects, and a statistical measure of spectral dynamics between two EEG signals in per frequency band was performed. Additionally, a bicoherence spectrum analysis was used to detect the phase coupling within these two imagery conditions. Our results indicated that EEG of the partial imagery appeared earlier and stronger than that of the holistic imagery in the theta (5-8 Hz) range in a time window around 220 to 300 ms after cue onset, and a slight decrease in the alpha (8-12 Hz) band was observed at around 270 ms. The scalp topography of these changes in the theta and alpha bands distributed overall significantly in the frontal and central-temporal areas. The significant phase coupling within two conditions was remarkable at high frequency. From these results, we infer that there are complex relations between partial and holistic imageries. The generation of partial mental imagery is not a subprocess of holistic imagery, but it is relevant to holistic imagery and requires correct modification from the holistic information.

Sex differences of event-related potential effects during three-dimensional mental rotation.

Sex differences in performance and in cortical activation patterns during mental rotation have rather consistently been reported. Data regarding sex differences of event-related potentials during the classic three-dimensional mental rotation task developed by Shepard and Metzler, however, are absent, and were therefore being addressed by this study. Mental rotation-related event-related potential effects were observed 900-1000 ms poststimulus at parietal electrodes and 600-700 as well as 800-900 ms poststimulus at right frontal leads, respectively. Sex differences, however, were observed already 400-700 ms poststimulus at right frontal electrodes. These findings suggest that sex differences during three-dimensional mental rotation occurred in relatively early cognitive processing stages presumably including perception and identification of stimuli instead of mental rotation itself.

Short-term meditation training improves attention and self-regulation.

Recent studies suggest that months to years of intensive and systematic meditation training can improve attention. However, the lengthy training required has made it difficult to use random assignment of participants to conditions to confirm these findings. This article shows that a group randomly assigned to 5 days of meditation practice with the integrative body-mind training method shows significantly better attention and control of stress than a similarly chosen control group given relaxation training. The training method comes from traditional Chinese medicine and incorporates aspects of other meditation and mindfulness training. Compared with the control group, the experimental group of 40 undergraduate Chinese students given 5 days of 20-min integrative training showed greater improvement in conflict scores on the Attention Network Test, lower anxiety, depression, anger, and fatigue, and higher vigor on the Profile of Mood States scale, a significant decrease in stress-related cortisol, and an increase in immunoreactivity. These results provide a convenient method for studying the influence of meditation training by using experimental and control methods similar to those used to test drugs or other interventions.