Understanding Motor Awareness Through Normal and Pathological Behavior

ABSTRACT— Data on patients with localized brain damage and on neurologically intact subjects show that normal motor control depends on the functionality of a chain of neurobiological events. These events, through the activation of internal representations of the desired, predicted, and actual condition of one's body with respect to the external world, contribute to the construction of conscious knowledge of voluntary actions and to self-awareness.     

非稳态噪声对动物行为及心脏自由基损伤的影响

本研究用采集的多用木工机床和冲击电钻发出的噪声对 5天、1 0天和 2 0天三个噪声干扰组的动物进行干扰 ,以研究非稳态噪声对动物行为及心脏组织自由基损伤的影响。结果发现 ,非稳态噪声可引起动物旷场反应中走格数减少 ,站立及洗脸次数增加 ,并可诱发心脏组织的自由基反应 ,导致心脏组织的损害。因此得出结论 :①非稳态噪声可以对动物行为产生影响 ,并随着噪声暴露时间的延长而增强 ;②非稳态噪声可以造成心脏组织的自由基损伤。这一现象提示自由基损伤是介导噪声对心脏功能影响的重要因素之一。     

Bilateral facilitation of motor control in chronic hemiplegia

The present study addressed the efficacy of concurrently moving both arms, with and without a load added to the uninvolved arm, in facilitating the quality of movement of the involved side in individuals with moderate, chronic hemiplegia. Six hemiplegic cerebrovascular accident (CVA) subjects with left-hemisphere lesions participated in the study. The four males and two females ranged from 46 to 77 years of age and 30–96 months post-CVA. All subjects scored at least 70% on the Fugl-Meyer test of motor function. The task was to perform discrete unilateral and bilateral elbow extensions in the horizontal plane. The movements were 45° in amplitude and were to terminate in a 10° target zone that was indicated by an illustration of a coffee mug. The instructions were to move toward the mug as smoothly as possible in a movement time (MT) determined to be 20% longer than their minimal MT for that distance. The primary dependent variable was the percentage of continuous vs. discontinuous trajectories observed in each condition, based on whether or not a transient hesitation or reversal was observed. Phase of peak velocity was also quantified as a general indication of the symmetry of the velocity profile. Three of the six subjects exhibited a greater percentage of continuous movements of the involved arm in the nonloaded bilateral condition than the unimanual condition. Five subjects benefited when the uninvolved arm was inertially loaded in the bilateral condition when compared with unimanual performance. Only the oldest subject failed to exhibit facilitation. Peak velocity phase tended to normalize toward symmetry in the bilateral conditions. These findings are consistent with prior evidence that the control of the involved arm improves during bimanual performance for some hemiplegic subjects. It further suggests loading the uninvolved arm may benefit some subjects with respect to unimanual performance, with age perhaps playing a role in determining efficacy.     

Preserved visual lexicosemantics in global aphasia: a right-hemisphere contribution?

Extensive testing of a patient, GP, who encountered large-scale destruction of left-hemisphere (LH) language regions was undertaken in order to address several issues concerning the ability of nonperisylvian areas to extract meaning from printed words. Testing revealed recognition of superordinate boundaries of animals, tools, vegetables, fruit, clothes, and furniture. GP was able to distinguish proper names from other nouns and from nonwords. GP was also able to differentiate words representing living things from those denoting nonliving things. The extent of LH infarct resulting in a global impairment to phonological and syntactic processing suggests LH specificity for these functions but considerable right-hemisphere (RH) participation in visual lexicosemantic processing. The relative preservation of visual lexicosemantic abilities despite severe impairment to all aspects of phonological coding demonstrates the importance of the direct route to the meaning of single printed words.     

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.     

The Electroconvulsive Therapy Controversy: Evidence and Ethics

The author reviews literature pertaining to the efficacy and safety of electroconvulsive therapy (ECT), with emphasis on the controversy concerning whether ECT causes brain damage. ECT does appear to be effective in the treatment of severe depression and possibly mania. The types of memory problems caused by ECT are discussed, and evidence suggests that most of these deficits are transitory. Although most evidence points toward modern ECT not causing brain damage, there are still some findings that raise questions about safety. Ethical issues involving this treatment's use, its availability to the public, and informed consent procedures are discussed.     

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.