语义距离半球效应的ERP研究

以通过视觉通路呈现的汉语双字词为实验材料,操纵启动词与目标词的语义距离。在词汇决定实验中记录ERP,发现：（1）除N300外,P240亦对语义距离敏感,它可能是一种与语义加工有关的新的ERP成分;（2）P240在头皮中央偏左的部位较早出现,但在头皮右侧波幅较大;（3）N300和P240都不存在语义距离的半球效应,该结果没有证实右脑更专擅远距离语义加工的假设,表明使用汉语与使用拼音文字的脑机制存在差异。     

Chronic violent video game exposure and desensitization to violence: Behavioral and event-related brain potential data

Numerous studies have shown that exposure to media violence increases aggression, though the mechanisms of this effect have remained elusive. One theory posits that repeated exposure to media violence desensitizes viewers to real world violence, increasing aggression by blunting aversive reactions to violence and removing normal inhibitions against aggression. Theoretically, violence desensitization should be reflected in the amplitude of the P300 component of the event-related brain potential (ERP), which has been associated with activation of the aversive motivational system. In the current study, violent images elicited reduced P300 amplitudes among violent, as compared to nonviolent video game players. Additionally, this reduced brain response predicted increased aggressive behavior in a later task. Moreover, these effects held after controlling for individual differences in trait aggressiveness. These data are the first to link media violence exposure and aggressive behavior to brain processes hypothetically associated with desensitization.     

Bi-hemispheric anodal transcranial direct current stimulation worsens taekwondo-related performance

Transcranial Direct Current Stimulation (tDCS) is a neuromodulatory technique that has been used as an ergogenic aid in exercise/sports performance. However, little is known about its effects on highly-trained subjects, as athletes. The present study aimed to verify the effects of bi-hemispheric anodal tDCS (a-tDCS) on the performance of taekwondo athletes. Additionally, we investigated the persistence of the effects of the a-tDCS one hour after it. Nineteen Taekwondo athletes received active or sham bi-hemispheric a-tDCS over the primary motor cortex (M1). a-tDCS was delivered at 1.5 mA for 15 min. Athletes performed Countermovement Jumps (CMJ) and the Frequency Speed of Kick Test (FSKT) immediately (Mo1) and one hour after stimulation (Mo2). The athletes also reported their session-rating of perceived exertion (session-RPE). The total number of kicks (TK) was higher in sham than in the active a-tDCS condition (p < 0.01). In addition, TK was higher at Mo2 than at Mo1 (p < 0.05). Similarly, the session-RPE was higher in the a-tDCS condition (p < 0.05) and was greater one-hour post-stimulation (p < 0.01). No differences were found for CMJ performance (p > 0.05). Thus, bi-hemispheric a-tDCS worsens performance of taekwondo athletes, and the effect remains present even 1 h after the stimulation.     

Emergent complexity: What uphill analysis or downhill invention cannot do

In these notes we review emergent phenomena in complex systems, emphasizing ways to identify potential underlying universal mechanisms that generate complexity. The discussion focuses on the emergence of collective behavior in dynamical systems when they are poised near a critical point of a phase transition, either by tuning or by self-organization. We then present the rationale for our proposal that the brain is naturally poised near criticality and review recent results as well as the implications of this view of the functioning brain.     

Autism Overflows: Increasing Prevalence and Proliferating Theories

This selective review examines the lack of an explanation for the sharply increasing prevalence of autism, and the lack of any synthesis of the proliferating theories of autism. The most controversial and most widely disseminated notion for increasing prevalence is the measles–mumps–rubella/thimerosal vaccine theory. Less controversial causes that have been proposed include changes in autism diagnostic criteria, increasing services for autism, and growing awareness of the disorder. Regardless of its causes, the increasing prevalence of autism has put pressure on the field of autism research to generate productive and predictive theories of autism. However, the heterogeneity of brain deficits, impaired behaviors, and genetic variants in autism have challenged researchers and theorists, and despite 45 years of research, no standard causal synthesis has emerged. Research going forward should assume that autism is an aggregation of myriad independent disorders of impaired sociality, social cognition, communication, and motor and cognitive skills.     

Comparison of chemosensory, auditory and visual event-related potential amplitudes

To enhance understanding of neuropsychological processing underlying chemosensory event-related potentials (CSERPs), the objective of the present study was to compare CSERPs with auditory (AERPs) and visual event-related potentials (VERPs), and to approach the question of similarities in neuropsychological processing by means of correlation and cluster analyses. A multisensory ERP protocol was used, in which olfactory/chemosomatosensory (pyridine), auditory (1000-Hz tone) and visual (white circle) stimuli were presented in a pseudo-randomized sequence to 18 young, healthy adults. The results show (1) a morphological relation between P2 and P3 components that is different for the chemosensory than for the auditory and visual modalities, (2) a relatively weak association between the chemosensory and auditory/visual modalities for P3 in terms of both correlation and cluster, and (3) a P2/P3 cluster for the chemosensory but not auditory or visual modality. This supports the claim that the chemosensory P2 and P3 components reflect similar neuropsychological processes.     

The thalamus and basal ganglia: What is exactly where?: A reply to ‘Neuropsychological consequences of right thalamic injury: Case study and review,’ MJ Summers, Brain and Cognition 50 (2002)

The present paper re-analyzes anatomical and clinical data of a previous case report ([Summers, 2002]). In this case study, a patient with severe neuropsychological and behavioral impairments is described and it is claimed that these impairments are causally linked to an right thalamic lesion. A simple method how to perform a lesion analysis is introduced which shows that PD’s lesion was a striatocapsular hematoma, and not a thalamic bleeding. The results of this anatomical re-analysis challenge the original behavioral-lesion hypothesis and emphasize the importance to provide appropriate data on brain lesions and clinical findings in neuropsychological case reports.     

Jolly fat rats? The effects of diet-induced obesity on territorial fighting

In experiment 1, pairs of young male rats became obese on a palatable and complex diet high in fat, sucrose, and protein. The obese pairs exhibited greater within-group weight variability and, when tested as adults, were significantly more aggressive toward an unfamiliar conspecific than chow-fed controls. The increased aggressivity of obese males was not due to the relatively larger resident-intruder weight disparities in these pairs, since weight-matched pairs of unfamiliar animals were as aggressive toward each other as pairs not matched in body weight (experiment 2). The complex and calorically dense diet may have accelerated the development of the experimental animals, producing subjects whose aggressivity was comparable to that of much older animals.     

Auditory evoked potentials and sex-related differences in brain development

Auditory evoked potentials (AEPs) were obtained to probe tones which were delivered during the presentation of complex verbal and nonverbal auditory stimulation to 3-month-old infants. Significant sex-dependent AEP amplitude asymmetries were found. Females produced higher-amplitude responses from the left hemisphere and males produced higher-amplitude responses from the right hemisphere during both the verbal and nonverbal presentations. No significant AEP asymmetries were obtained in an independent group of infants that received only the probe tones. These findings are consistent with theories and behavioral data suggesting differences between males and females in the development of language and spatial functions.