大脑两半球与整体和局部性质的选择性加工

研究大脑两半球在加工整体和局部性质中的优势以及两半球能否同时分别选择两个复合刺激的整体和局部性质。实验中把一个复合字母随机呈现在左视野或右视野,或者把两个复合字母同时分别呈现在左视野和右视野。实验一发现,在单侧呈现条件下,被试检测左右视野的整体或局部靶目标的反应时没有显著差别,但在双侧同时呈现条件下,检测右视野局部靶目标比检测左视野局部靶目标时的反应时短。实验二要求被试检测同时呈现在左右视野的整体或局部靶目标,发现当两个视野的靶目标处于同一水平时(整体或局部)反应时较短,两个视野的靶目标处于不同水平时(一侧处于整体水平而另一侧处于局部水平)反应时较长。这些结果提示,当两个复合刺激同时呈现在左右视野时,大脑左半球在选择性加工局部性质时具有优势;左右两半球更容易选择两个复合刺激同一个水平的性质,分别选择两个复合刺激不同水平的性质比较困难。     

Afferent dysgraphia after right cerebral stroke: an autonomous syndrome?

Afferent dysgraphia is an acquired writing deficit characterized by deletions and duplications of letters and strokes. The commonly accepted interpretation states that afferent dysgraphia is associated with three main clinical features: production of spatial writing errors; the presence of left unilateral neglect; and no deterioration in performance when writing blindfolded. In order to test whether these symptoms necessarily co-occur with afferent dysgraphia, we studied the writing performances of a series of eight right brain-damaged patients. In sentence copying, spontaneous handwriting, and writing to dictation they showed afferent dysgraphia. However, signs of left neglect and spatial dysgraphia were evident only in some cases. Furthermore, the frequency of afferent errors increased when patients were required to write without vision. The present study demonstrates that afferent dysgraphia is an autonomous clinical entity and that it results from a selective impairment of a mechanism whose function is that of comparing the information about the number of letters and strokes specified at the level of letter motor programs and the actual number of movements already realized.     

Implicit self and the right hemisphere: Increasing implicit self‐esteem and implicit positive affect by left hand contractions

Unilateral hand contraction typically activates the contralateral hemisphere and has led to changes in psychological states and performances in previous research. Based on a right hemisphere model of the implicit self, we hypothesized and found that left hand contraction increases momentary levels of implicit self‐esteem (Studies 1 and 2) and implicit positive affect (Study 3). The findings are discussed with respect to potential differences between the hemispheres in implicit and explicit affective processing and how they can be integrated in the existing literature on hemisphere asymmetries.     

国外关于右脑的语言功能研究的进展

对国外有关右脑语言功能的研究作了简要概述,对研究中达成的共识和存在的分歧作了初步介绍;在此基础上,对有关右脑的语言功能研究意义和趋势作了概括和预测。从而为国内相关研究提供借鉴和启示。     

Individual differences in risk perception versus risk taking: handedness and interhemispheric interaction

Research indicates that right-hemisphere mechanisms are specifically sensitive to and averse to risk. Research also indicates that mixed degree of handedness is associated with increased access to right hemisphere processing. Accordingly, it was predicted that mixed-handers would exhibit greater risk aversion. Participants were presented with various risky activities and were asked to rate (i) the perceived risk, (ii) the perceived benefit, and (iii) their likelihood to engage in each activity. No handedness differences were found for any of these ratings. Regression analyses, however, indicated that the likelihood to engage in risky activities was predicted primarily by the perceived risks in mixed-handers and by the perceived benefits in strong-handers.     

South African International Migration and its Impact on Older Family Members

In this article, we explore the impact of South African families’ emigration on parents/grandparents who must renegotiate their lives in their loved ones’ physical absence. We adopted a transnational perspective in a bigger qualitative project to consider both sides of the migratory spectrum. Here we focus on elderly family members who remain behind—a group largely neglected in prior research. Our findings illustrate the complex emotions and relational changes experienced by elderly people whose families emigrate. New technologies bridge distances, allowing new ways to connect and take care of each other, and of re-imagining transnational relationships and what constitutes family life, but these bridges cannot negate the loss experienced by those remaining. People have to make sense of the emigration and forge new relational bonds with remaining family members. Our findings stress grandparents’ meaningful role in a family system and highlight some gendered and racial differences in families’ experiences.     

The right hemispheric dominance for face perception in preschool children depends on the visual discrimination level

The developmental origin of human adults’ right hemispheric dominance in response to face stimuli remains unclear, in particular because young infants’ right hemispheric advantage in face‐selective response is no longer present in preschool children, before written language acquisition. Here we used fast periodic visual stimulation (FPVS) with scalp electroencephalography (EEG) to test 52 preschool children (5.5 years old) at two different levels of face discrimination: discrimination of faces against objects, measuring face‐selectivity, or discrimination between individual faces. While the contrast between faces and nonface objects elicits strictly bilateral occipital responses in children, strengthening previous observations, discrimination of individual faces in the same children reveals a strong right hemispheric lateralization over the occipitotemporal cortex. Picture‐plane inversion of the face stimuli significantly decreases the individual discrimination response, although to a much smaller extent than in older children and adults tested with the same paradigm. However, there is only a nonsignificant trend for a decrease in right hemispheric lateralization with inversion. There is no relationship between the right hemispheric lateralization in individual face discrimination and preschool levels of readings abilities. The observed difference in the right hemispheric lateralization obtained in the same population of children with two different paradigms measuring neural responses to faces indicates that the level of visual discrimination is a key factor to consider when making inferences about the development of hemispheric lateralization of face perception in the human brain.     

Frontal Lobe Function and Pain in the Elderly

We review the literature on pain and aging and conclude that evidence supports a hypothesis that right frontal cortex contributes to the mediation of the chronic pain experience in elderly persons with chronic pain syndromes. Evidence for the right frontal pain hypothesis comes from clinical, neurocognitive, and neuroimaging studies, which implicate right inferior and orbitofrontal cortex in (1) the persistent pain experience, (2) negative emotional states, (3) retrieval of negative emotional and autobiographical memories, (4) regulation of autonomic arousal, and (5) regulation of attentional and pain functions of the anterior cingulate region. Right frontal dysfunction is also implicated in the effects of cognitive aging. If right frontal neurocognitive systems are affected in cognitively impaired elderly, and if (by hypothesis) the right frontal cortex also plays a major role in the experience of chronic pain, then cognitively impaired elderly with right frontal dysfunction should be protected to some extent from persistent pain syndromes. Available evidence supports this proposition.     

Covert reading of letters in a case of global alexia

This study describes the case of a global alexic patient with a severe reading deficit affecting words, letters and Arabic numbers, following a left posterior lesion. The patient (VA) could not match spoken letters to their graphic form. A preserved ability to recognize shape and canonical orientation of letters indicates intact access to the representation of letters and numbers as visual objects. A relatively preserved ability to match lowercase to uppercase letters suggests partially spared access to abstract letter identities independently of their visual forms. The patient was also unable to match spoken letters and numbers to their visual form, indicating that she could not access the graphemic representations of letters from their phonological representations. This pattern of performance suggests that the link between graphemic and phonological representations is disrupted in this patient. We hypothesize that VA’ residual reading abilities are supported by the right hemisphere.     

The role of the right hemisphere in speech act comprehension

In this research the role of the RH in the comprehension of speech acts (or illocutionary force) was examined. Two split-screen experiments were conducted in which participants made lexical decisions for lateralized targets after reading a brief conversation remark. On one-half of the trials the target word named the speech act performed with the preceding conversation remark; on the remaining trials the target did not name the speech act that the remark performed. In both experiments, lexical decisions were facilitated for targets representing the speech act performed with the prior utterance, but only when the target was presented to the left visual field (and hence initially processed by the RH) and not when presented to the right visual field. This effect occurred at both short (Experiment 1: 250 ms) and long (Experiment 2: 1000 ms) delays. The results demonstrate the critical role played by the RH in conversation processing.