Hemihypokinesia after right hemisphere stroke

We tested the hypothesis that the right hemisphere is dominant for motor activation of "intention." If the right hemisphere is dominant for intention and if intention is a prerequisite for movement, motor impairment should be worse after an infarct in the right hemisphere than in the left. We asked nine subjects with right and nine with left hemisphere infarcts to elevate each shoulder independently. Subjects with right hemisphere lesions had more trouble moving the contralateral shoulder. The data are consistent with the hypothesis that the right hemisphere is dominant for motor activation or intention.     

Motherhood: a potential source of bias in employment decisions

Results of 2 experimental studies in which job incumbents were said to be applying for promotions to traditionally male positions demonstrated bias against mothers in competence expectations and in screening recommendations. This bias occurred regardless of whether the research participants were students (Study 1) or working people (Study 2). Although anticipated job commitment, achievement striving, and dependability were rated as generally lower for parents than for nonparents, anticipated competence was uniquely low for mothers. Mediational analyses indicated that, as predicted, negativity in competence expectations, not anticipated job commitment or achievement striving, promoted the motherhood bias in screening recommendations; expected deficits in agentic behaviors, not in dependability, were found to fuel these competence expectations. These findings suggest that motherhood can indeed hinder the career advancement of women and that it is the heightened association with gender stereotypes that occurs when women are mothers that is the source of motherhood's potentially adverse consequences.     

Affective aprosodia from a medial frontal stroke

BACKGROUND AND OBJECTIVES: Whereas injury to the left hemisphere induces aphasia, injury to the right hemisphere's perisylvian region induces an impairment of emotional speech prosody (affective aprosodia). Left-sided medial frontal lesions are associated with reduced verbal fluency with relatively intact comprehension and repetition (transcortical motor aphasia), but persistent affective prosodic defects associated with right medial frontal lesions have not been described. METHODS: We assessed the prosody of a man who sustained a right medial frontal cerebral infarction seven years prior. RESULTS: While propositional speech expression was normal including syntactic prosody, the patient was impaired at expressing emotions using prosody. His comprehension and repetition of prosody were also impaired but less so than expression. CONCLUSIONS: Right medial frontal lesions can induce an affective aprosodia that primarily impairs expression.     

Choice or circumstance: When are women penalized for their success?

Past research shows that successful women in traditionally masculine roles often experience interpersonal penalties not sustained by similarly successful men. In two studies we, addressed the question of how the perceived motivation of women for counter-stereotypical positions affects whether such penalties occur. Specifically, we investigated whether women who are successful in male gender-typed roles are less likely to be penalized when their attainment of the role is due to circumstance than to focused and intentional goal pursuit. In Study 1, we compared reactions to women and men who had been successful in a leadership role on a STEM project and showed that when a woman had been arbitrarily assigned to the leadership role she incurred fewer interpersonal penalties than when she had actively pursued it. In Study 2, we replicated and extended these findings by demonstrating similar effects for a successful woman in a financial position when she had attained her position due to a series of lucky breaks rather than purposeful goal-directed efforts. The results of these studies support the idea that the perception that women have actively chosen to pursue counter-normative goals plays an important role in determining whether they are penalized for their success in traditionally male domains. It was not simply being in the role, but how she got there, that determined whether the derogation and dislike shown to be directed at successful women in past research occurred.     

Right up there: hemispatial and hand asymmetries of altitudinal pseudoneglect

Background

Pseudoneglect is a normal left sided spatial bias observed with attempted bisections of horizontal lines and a normal upward bias observed with attempted bisections of vertical lines. Horizontal pseudoneglect has been attributed to right hemispheric dominance for the allocation of attention. The goal of this study was to test the hypothesis that the upward bias in vertical line bisection may also relate to right hemispheric dominance for the allocation of attention and/or action-intention.

Methods

Twenty right handed healthy adults were asked to bisect vertical lines presented in the midsagittal plane (center space) and in sagittal planes to the left and right of the midsagittal plane (left and right hemispace) when using a pen held in either the right or left hand.

Results

Vertical line bisections were biased upward in all three sagittal planes and higher in left than right hemispace. However, bisections made with the left hand were lower than those made with the right hand.

Discussion

Whereas these results suggest a left hemispace-right hemispheric visuospatial attentional upward bias and a relative left hemispheric-right hand upward action-intentional bias, further studies are needed to document this intentional versus attentional bias and to understand the brain mechanisms that produce these biases.     

Recall of word lists is enhanced with increased spreading activation

ABSTRACT

Some evidence exists supporting a relationship between spreading activation in semantic/lexical memory networks and episodic memory. However, the results have been mixed and there have been no investigations examining whether a relationship exists between variability in spreading activation and episodic memory. Hence, we sought to investigate these potential relationships. Thirteen individuals were administered the Hopkins Verbal Learning Test–Revised (HVLT-R) and the Controlled Oral Word Association Test (COWAT). The average word frequency of all the “F” words generated on the COWAT was used as a measure of spreading activation. Variability in spreading activation was assessed by calculating the variability of the word frequencies from the COWAT across time. The results confirmed our hypotheses, with significant negative correlations found between free recall on the HVLT-R and both the average word frequency and measures of variability in spreading activation.     

Apraxia in corticobasal degeneration.

Corticobasal degeneration (CBD) is a degenerative disease that often presents with an asymmetric progressive ideomotor limb apraxia. Some apraxic subjects may fail to perform skilled purposive movements on command because they have lost the memories or representations that specify how these movements should be performed (representational deficit). In contrast, other apraxic subjects may have the movement representations but are unable to utilize the information contained in them to execute skilled purposive movements (production-execution deficit). To learn if the apraxic deficit in CBD is induced by a representational or a production-execution deficit, we tested three nondemented subjects with CBD on tasks requiring production of meaningful or meaningless gestures to command, gesture imitation, gesture discrimination, and novel gesture learning. A fourth subject with incomplete data also is presented. The results suggest that the apraxia associated with CBD is initially induced by a production-execution defect with relative sparing of the movement representations.     

Linguistic semantic agraphia: A dissociation of the lexical spelling system from semantics

Two spelling systems have been described. The phonological system transcodes speech sounds to letters and is thought to be useful for spelling regular words and pronounceable nonwords. Although the second system, the lexical-semantic system, is thought to use visual word images and meaning to spell irregular words, it is not known if this system is dependent on semantic knowledge. We used a homophone spelling test to examine the lexical-semantic system in five patients. The patients were asked to spell individual homophones (doe or dough) using the context of a sentence. Semantically incorrect and correct homophones were spelled equally well, whether they were regular or irregular. These results demonstrate that an irregular word may be spelled without knowledge of the word's meaning. Therefore, the lexical system can be dissociated from semantic influence.     

Reading: dissociation of the lexical and phonologic mechanisms

Three distinct reading mechanisms have been proposed: the phonologic conversion system in which letters are converted to their sound equivalents (phonemes) before meaning is established, and two lexical or whole-word mechanisms in which a word (or root morpheme) is identified as a single unit rather than by phonologic conversion. The two lexical mechanisms differ in that one is inextricably linked to semantics but the other is not. The phonologic conversion system may depend more on the perisylvian phonologic system than do the lexical mechanisms, which may be mediated by left parietal or occipital areas or by the right hemisphere. Described here is a patient who had an infarction that partially isolated the perisylvian speech areas and disconnected the partially preserved lexical systems from the phonologic mechanism. He read visually presented orthographically irregular words but could not pronounce orally spelled irregular words. Although he could not read nonwords, he could pronounce orally spelled nonwords and orthographically regular words. These observations suggest that the lexical and phonologic conversion systems are functionally and anatomically distinct.