无意识活动与静息态脑能量消耗

静息态脑活动的研究关注个体在清醒、静卧、闭眼时脑的活动情况,大量实验证明静息状态下大脑仍进行着持续不断的信息加工活动,并且消耗大量能量。本文在阐述无意识活动特性以及总结静息态脑能量消耗研究的基础上,提出用无意识活动解释静息态脑能量消耗的观点,强调在研究无意识活动的心理意义的同时,还要研究无意识活动的神经机制及其生理表现。     

Modeling the Ecological Validity of Neurocognitive Assessment in Adults with Acquired Brain Injury

Neuropsychologists are increasingly asked to make judgments regarding treatment options and rehabilitation strategies in addition to evaluating the degree and scope of neuropsychological impairment following acquired brain injuries. The capacity to make informed clinical decisions relies upon research investigating the relationships between neuropsychological and psychosocial status (i.e., ecological validity). Unfortunately, much of this research employs exploratory analyses, an approach that can lead to theoretical ambiguity and ad-hoc interpretations. The current availability and accessibility of analytical tools, like structural equation modeling (SEM), however, permits the testing of specific hypotheses regarding ecological validity and promotes a-priori theory development. In the current study, a theory-driven model of the ecological validity of a neurocognitive assessment was tested against data obtained from individuals with acquired brain injury using SEM. The results provide confirmatory evidence for the ecological validity of neurocognitive constructs and empirical support for a theory-driven analytical approach to ecological validity research.     

Valence specific laterality effects in prosody: expectancy account and the effects of morphed prosody and stimulus lead

The majority of studies have demonstrated a right hemisphere (RH) advantage for the perception of emotions. Other studies have found that the involvement of each hemisphere is valence specific, with the RH better at perceiving negative emotions and the LH better at perceiving positive emotions [Reuter-Lorenz, P., & Davidson, R.J. (1981) Differential contributions of the 2 cerebral hemispheres to the perception of happy and sad faces. Neuropsychologia, 19, 609-613]. To account for valence laterality effects in emotion perception we propose an 'expectancy' hypothesis which suggests that valence effects are obtained when the top-down expectancy to perceive an emotion outweighs the strength of bottom-up perceptual information enabling the discrimination of an emotion. A dichotic listening task was used to examine alternative explanations of valence effects in emotion perception. Emotional sentences (spoken in a happy or sad tone of voice), and morphed-happy and morphed-sad sentences (which blended a neutral version of the sentence with the pitch of the emotion sentence) were paired with neutral versions of each sentence and presented dichotically. A control condition was also used, consisting of two identical neutral sentences presented dichotically, with one channel arriving before the other by 7 ms. In support of the RH hypothesis there was a left ear advantage for the perception of sad and happy emotional sentences. However, morphed sentences showed no ear advantage, suggesting that the RH is specialised for the perception of genuine emotions and that a laterality effect may be a useful tool for the detection of fake emotion. Finally, for the control condition we obtained an interaction between the expected emotion and the effect of ear lead. Participants tended to select the ear that received the sentence first, when they expected a 'sad' sentence, but not when they expected a 'happy' sentence. The results are discussed in relation to the different theoretical explanations of valence laterality effects in emotion perception.     

Responsiveness and functional connectivity of the scene-sensitive retrosplenial complex in 7–11-year-old children

Brain imaging studies have identified two cortical areas, the parahippocampal place area (PPA) and the retrosplenial complex (RSC), that respond preferentially to the viewing of scenes. Contrary to the PPA, little is known about the functional maturation and cognitive control of the RSC. Here we used functional magnetic resonance imaging and tasks that required attention to scene (or face) images and suppression of face (or scene) images, respectively, to investigate task-dependent modulation of activity in the RSC and whole-brain functional connectivity (FC) of this area in 7–11-year-old children and young adults. We compared responsiveness of the RSC with that of the PPA. The RSC was selectively activated by scene images in both groups, albeit less than the PPA. Children modulated activity between the tasks similarly in the RSC and PPA, and to the same extent as adults in PPA, whereas adults modulated activity in the RSC less than in PPA. In children, the whole brain FC of the RSC was stronger in the Sf than Fs task between the left RSC and right fusiform gyrus. The between groups comparison suggested stronger FC in children than adults in the Sf task between the right RSC and the left inferior parietal lobule and intraparietal sulcus. Together the results suggest that the function of the RSC and the related networks undergo dynamic changes over the development from 7–11-year-old children to adulthood.     

The association of physical activity to occipito-temporal processing during face recognition

ObjectivesThis study examined the association between physical activity level and primitive cognitive processing during a face recognition task in young adults, a topic that has received little attention.DesignCross-sectional.MethodsThe face recognition task required participants to respond to famous faces but not respond to unfamiliar faces. Task performance and several occipito-temporal event-related brain potentials reflecting the various stages of face processing, from perceptual encoding (N170) to recognition (N250 and face-N400), were assessed during the face recognition task.ResultsAlthough analyses revealed no significant group differences in behavioral performance measures, neuroelectric data showed different time courses of face recognition processes between groups. Active individuals exhibited larger N250 amplitude, reflecting an early stage of facial recognition, for famous relative to unfamiliar faces, whereas inactive individuals did not exhibit such a difference.ConclusionsThese findings are suggestive of a possible association between physical activity and relatively early, primitive cognitive processes.     

Conscious and unconscious processing of facial expressions: Evidence from two split‐brain patients

We investigated how the brain's hemispheres process explicit and implicit facial expressions in two ‘split‐brain’ patients (one with a complete and one with a partial anterior resection). Photographs of faces expressing positive, negative or neutral emotions were shown either centrally or bilaterally. The task consisted in judging the friendliness of each person in the photographs. Half of the photograph stimuli were ‘hybrid faces’, that is an amalgamation of filtered images which contained emotional information only in the low range of spatial frequency, blended to a neutral expression of the same individual in the rest of the spatial frequencies. The other half of the images contained unfiltered faces. With the hybrid faces the patients and a matched control group were more influenced in their social judgements by the emotional expression of the face shown in the left visual field (LVF). When the expressions were shown explicitly, that is without filtering, the control group and the partially callosotomized patient based their judgement on the face shown in the LVF, whereas the complete split‐brain patient based his ratings mainly on the face presented in the right visual field. We conclude that the processing of implicit emotions does not require the integrity of callosal fibres and can take place within subcortical routes lateralized in the right hemisphere.     

神经成像读心中的认知本体论疑难

认知神经科学的研究者们在使用神经成像技术进行读心时,运用到了反向推理和大脑解码两种策略。但目前相关研究中所涉及的同一认知过程或心理功能的具体内涵并不统一,反映出认知神经科学部分术语存在定义混乱的现象。这一方面使得反向推理面临相关脑区缺乏选择性的难题,另一方面也限制了大脑解码的准确率。对此最有希望的一种解决办法是建立认知本体论,可它仍然在技术、方法以及哲学三个层面上存在疑难,这削弱了利用神经成像去读取他人思想这一做法的可靠性及合理性。

     

关于二类疫苗医疗损害责任类型化的思考

基于法的规范分析,二类疫苗预防接种损害责任的法律关系及性质比较复杂,体现了违约与侵权责任的竞合,兼具一般医疗技术损害责任和医疗产品责任的双重性质,由此导致其损害责任的构成要件、案由选择、法律适用及救济路径也各不相同。二类疫苗预防接种技术损害责任采用过错归责原则,而二类疫苗的产品损害责任适用无过错归责原则,疫苗的产品责任属于不真正连带责任。深入分析二类疫苗损害责任的性质,有助于厘清其损害责任的承担,促进其损害救济体系的完善。     

大脑电刺激在听觉语言加工研究中的应用

大脑电刺激是历史悠久但近年来才广泛应用在人类被试上的实验技术。通过对颅内刺激位点进行电刺激, 并分析引发的暂时性行为功能变化和记录位点的电位活动, 大脑电刺激技术可以揭示认知加工过程中脑区内的功能作用与脑区间的有效连接。通过对听觉语言加工过程相关的丘脑、听觉皮层、高级语言皮层进行电刺激, 现有研究发现了各个脑区的不同功能特点以及不同脑区间的信息传递机制, 为进一步探索听觉语言加工的神经机制提供了新的视角。