Repetition priming reveals hemispheric differences in compound word processing

The left (LH) and right (RH) hemispheres are thought to implement different mechanisms for visual word recognition; the LH’s parallel encoding strategy is more efficient than the RH’s serial, letter-by-letter analysis. Here we examine differences in hemispheric language processing strategy by investigating repetition priming of compound words (e.g. buttercup) and their constituents (e.g. butter, cup). Eighty-eight right-handed participants (29 M, 59 F) completed a lexical decision experiment in which centrally-presented compounds primed related (whole compound, first constituent, second constituent) and unrelated targets presented laterally to the left or right visual field; participants made button-press word/nonword decisions. Consistent with the LH parallel/RH serial distinction, repetition priming prompted an RH advantage for first constituents, whereas the LH performed equally efficiently in response to both first and second constituents. These data thus highlight differences in the hemispheres’ language processing strategies, offering new evidence supporting a relative parallel/serial distinction in LH/RH visual word recognition.     

Does Traumatic Brain Injury Attenuate the Exposure Therapy Process?

Research indicates that exposure therapy is efficacious for combat-related posttraumatic stress disorder (PTSD) comorbid with traumatic brain injury (TBI) as is shown by reduced PTSD treatment outcome scores. What is unknown, however, is whether the process of fear extinction is attenuated in veterans with TBI history. Increased PTSD symptomatology and possible cognitive deficits associated with TBI sequelae may indicate additional or longer exposure sessions to achieve habituation and extinction comparable to individuals without TBI history. As such, a more extensive course of treatment may be necessary to achieve comparable PTSD treatment outcome scores for individuals with TBI history. Using a sample of veterans with combat-related PTSD, some of whom were comorbid for TBI, this study compared process variables considered relevant to successful treatment outcome in exposure therapy. Individuals with and without TBI demonstrated similar rates of fear activation, length and number of exposure sessions, within-session habituation, between-session habituation, and extinction rate; results remained consistent when controlling for differential PTSD symptomatology. Furthermore, results indicated that self-perception of executive dysfunction did not impact the exposure process. Results suggest that individuals with PTSD and TBI history engage successfully and no differently in the exposure therapy process as compared to individuals with PTSD alone. Findings further support exposure therapy as a first-line treatment for combat-related PTSD regardless of TBI history.     

“集体主义—个体主义”的差异:来自基因、大脑的证据

文章以"集体主义—个体主义"这一基本文化差异维度为基础,围绕文化、基因和大脑之间的关系,介绍了国内外最新研究进展。研究显示当人类执行各种文化任务时,那些为人类生存提供有力帮助的基因会被选择和保留下来;在自我表征,注意和知觉,决策、情绪和意向推断等心理状态或过程上的"集体主义—个体主义"文化差异都可追溯到脑功能的差异。研究者先后提出社会脑假设、文化—基因协同进化论、神经—文化交互作用模型等理论来解释基因、文化与大脑交互作用的现象。文章分析了当前研究中存在的问题,并对未来的研究进行了展望。     

A dissociation between selective attention and conscious awareness in the representation of temporal order information

Previous electrophysiological studies have shown that attentional selection processes are highly sensitive to the temporal order of task-relevant visual events. When two successively presented colour-defined target stimuli are separated by a stimulus onset asynchrony (SOA) of only 10 ms, the onset latencies of N2pc components to these stimuli (which reflect their attentional selection) precisely match their objective temporal separation. We tested whether such small onset differences are accessible to conscious awareness by instructing participants to report the category (letter or digit) of the first of two target-colour items that were separated by an SOA of 10, 20, or 30 ms. Performance was at chance level for the 10 ms SOA, demonstrating that temporal order information which is available to attentional control processes cannot be utilized for conscious temporal order judgments. These results provide new evidence that selective attention and conscious awareness are functionally separable, and support the hypothesis that attention and awareness operate at different stages of cognitive processing.     

Comparison of brain mechanisms underlying the processing of Chinese characters and pseudo-characters: an event-related potential study

Most Chinese characters are composed of a semantic radical on the left and a phonetic radical on the right. The semantic radical provides the semantic information; the phonetic radical provides information concerning the pronunciation of the whole character. The pseudo‐characters in the study consisted of different sub‐lexical parts of real Chinese characters and consequently they also had the semantic radical and the phonetic radical. But they were not readable and had no actual meaning. In order to investigate the spatiotemporal cortical activation patterns underlying the orthographic, phonological and semantic processing of Chinese characters, we used event‐related brain potentials (ERPs) to explore the processing of Chinese characters and pseudo‐characters when 14 healthy Chinese college students viewed the characters passively. Results showed that both Chinese characters and pseudo‐characters elicited an evident negative potential peaking around 120 ms (N120), which appeared to reflect initial orthographic distinction and evaluation. Then, Chinese pseudo‐characters elicited a more positive ERP deflection (P220) than did Chinese characters 200–250 ms after onset of the stimuli. It was similar to the recognition potential (RP) and might reflect the integration processes of phonological and semantic processing on the basis of early orthographic information. Dipole source analysis of the difference wave (pseudo‐characters minus characters) indicated that a generator localized in the left temporal‐occipital junction contributed to this effect, which was possibly related to phonological and perceptual–semantic information integration. Between 350–450 ms, a greater negativity (N360) in pseudo‐characters as compared to characters was found over midline fronto‐central scalp regions. Dipole analysis localized the generator of N360 in the right parahippocampal cortex. Therefore, the N360 might be an N400 component and reflect the higher‐level semantic activation on the basis of orthographic, phonological and perceptual–semantic processing.     

Effects of Accelerated Reading Rate on Processing Words' Syntactic Functions by Normal and Dyslexic Readers: Event Related Potentials Evidence

In the present study, the authors examined differences in brain activity, as measured by amplitudes and latencies of event related potentials (ERP) components, in Hebrew-speaking adult dyslexic and normal readers when processing sentence components with different grammatical functions. Participants were 20 dyslexic and 20 normally reading male college students aged 18–27 years. The authors examined the processing of normal word strings in word–by-word reading of sentences having subject-verb-object (SVO) syntactic structure in self- and fast-paced conditions. Data revealed that in both reading conditions, the N100 and P300 ERP components were sensitive to internal processes such as recognition of words' grammatical functions. However, the results revealed that fast-paced reading rate might affect this process, as was reflected in the systematic changes of amplitudes and latencies of both ERP components. In accelerated reading, a significant decrease of latencies and increase of amplitudes in dyslexics were shown. It was also found that influence of fast-paced reading rate was realized in the full usage of the word-order strategy in sentence processing. In turn, this fact confirmed the hypothesis concerning a syntactic processing “weakness” in dyslexia.     

Executive functions and social skills in survivors of pediatric brain tumor

Medical advances have resulted in increased survival rates for children with brain tumors. Consequently, issues related to survivorship have become more critical. The use of multimodal treatment, in particular cranial radiation therapy, has been associated with subsequent cognitive decline. Specifically, deficits in executive functions have been reported in survivors of various types of pediatric brain tumor. Survivors are left with difficulties, particularly in self-monitoring, initiation, inhibition, and planning, to name a few. Another domain in which survivors of pediatric brain tumor have been reported to show difficulty is that of social skills. Parents, teachers, and survivors themselves have reported decreased social functioning following treatment. Deficits in executive functions and social skills are likely interrelated in this population, as executive skills are needed to navigate various aspects of social interaction; however, this has yet to be studied empirically. Twenty-four survivors of pediatric brain tumor were assessed using a computerized task of executive functions, as well as paper-and-pencil measures of social skills and real-world executive skills. Social functioning was related to a specific aspect of executive functions, that is, the survivors' variability in response time, such that inconsistent responding was associated with better parent-reported and survivor-reported social skills, independent of intellectual abilities. Additionally, parent-reported real-world global executive abilities predicted parent-reported social skills. The implications of these findings for social skills interventions and future research are discussed.