The association of macro- and microstructure of the corpus callosum and language lateralisation

The present study aimed to examine how differences in functional lateralisation of language are related to interindividual variations in interhemispheric connectivity. Utilising an fMRI silent word-generation paradigm, 89 left- and right-handed subjects were subdivided into four lateralisation subgroups. Applying morphological and diffusion-tensor MRI, midsagittal cross-sectional area as well as quantitative measures of molecular diffusion (anisotropy, mean diffusion) of the corpus callosum were determined to assess interhemispheric connectivity. Statistical analyses revealed group differences in molecular diffusion but not in callosal size, which may be interpreted to reflect a stronger and/or faster interhemispheric connection in strongly left-lateralised subjects as compared to moderately left-lateralised, bilateral, or moderately right-lateralised subjects.     

The premodern and the postmodern: Some parallels,with special reference to Hinduism

Insofar as the postmodern exists, it is held to represent a break with the modern, a break no less radical than that of the modern with the premodern. In this paper I point to certain similarities between on the one hand what are said to be key aspects of the postmodern and on the other hand the premodern. It may well be fruitful to look for further parallels on either side of modernity.     

Communicative deficits in agenesis of the corpus callosum: nonliteral language and affective prosody

While some individuals with agenesis of the corpus callosum can perform normally on standardized intelligence tests, clinical observations suggest that they nevertheless have deficits in the domains of fluid and social intelligence. Particularly important for social competence is adequate understanding and use of paralinguistic information. This study examined the impact of callosal absence on the processing of pragmatic and paralinguistic information. Young adult males with agenesis of the corpus callosum (ACC) were evaluated in the areas of nonliteral language comprehension, proverb recognition and interpretation, and perception of affective prosody. Ten ACC individuals with normal Wechsler IQ were compared to 14 sex, age, and IQ matched normal controls. The Formulaic and Novel Language Comprehension Test (FANL-C), Gorham Proverbs Test, and LA Prosody Test were administered. ACC subjects exhibited significant impairment on the nonliteral items of the FANL-C, but no significant difference from controls in comprehension of literal items. ACC subjects also exhibited significant deficits in both self-generated interpretation and recognition of proverb meaning, and in recognition of affective prosody. These results demonstrate that normally intelligent individuals with ACC are impaired in the understanding of nonliteral language and emotional-prosodic cues that are important in social communication. In all three tests, the performance of individuals with ACC was similar to patients with right hemisphere brain damage. Thus, persons with ACC appear to lack interhemispheric integration of critical aspects of language processed by the right hemisphere.     

The corpus callosum and cerebral speech lateralization

In order to specify the callosal involvement in the establishment of cerebral lateralization, a dichotic listening task was administered to six subjects with congenital absence of the corpus callosum, two callosotomized patients, and two hemispherectomized patients. The acallosal subjects were also compared to six subjects matched for age, sex, and hand dominance as well as to six subjects also matched for IQ. Our findings indicate that language functions, as assessed by dichotic listening performance, are more strongly lateralized in callosal agenesis subjects than in IQ-matched normal controls. Our results also reveal that hemispherectomized patients typically show a strong ear-advantage favoring the ear contralateral to their remaining hemisphere. Callosotomized patients, on the other hand, show a more variable pattern of results that seems to be related to the postsurgical time interval. Finally, our findings suggest that there might be a relationship between IQ and lateralization in subjects with borderline or mild deficiency.     

Aspects of language in children with ADHD: applying functional analyses to explore language use

This article reports some outcomes from an exploratory study that compares children diagnosed with ADHD and without language impairment with typically developing children for aspects of language use. Discourse analysis based on a systemic functional linguistics approach is applied to spoken and written samples from three different text types that are supplied by 11 children diagnosed with ADHD and 11 typically developing children. Comparisons of multiple variables most often show differences in use between the groups. Closer examination of these differences shows that relative to the controls, the ADHD group uses fewer strategies of textual organization and more avoidance, tangential, and unrelated meanings and more abandoned utterances and spelling and punctuation errors. Clinical implications suggest that careful linguistic analysis of spoken and written language of children with ADHD cannot only identify the linguistic resources they use within everyday contexts but may also indicate areas where intervention may be beneficial.     

Idiom comprehension deficits in relation to corpus callosum agenesis and hypoplasia in children with spina bifida meningomyelocele

Idioms are phrases with figurative meanings that are not directly derived from the literal meanings of the words in the phrase. Idiom comprehension varies with: literality, whether the idiom is literally plausible; compositionality, whether individual words contribute to a figurative meaning; and contextual bias. We studied idiom comprehension in children with spina bifida meningomyelocele (SBM), a neurodevelopmental disorder associated with problems in discourse comprehension and agenesis and hypoplasia of the corpus callosum. Compared to age peers, children with SBM understood decomposable idioms (which are processed more like literal language) but not non-decomposable idioms (which require contextual analyses for acquisition). The impairment in non-decomposable idioms was related to congenital agenesis of the corpus callosum, which suggests that the consequences of impaired interhemispheric communication, whether congenital or acquired in adulthood, are borne more by configurational than by compositional language.     

The nature of equity-restoration: Some approval-seeking considerations

Subjects performed a proofreading task and evaluated its difficulty both beforehand and afterwards. They were overpaid or equitably paid by an experimenter who was or was not directly responsible for the level of pay they received, and who they believed would or would not see their post-test ratings. All subjects knew the experimenter would grade their task performance. Consistent with equity theory, overpaid subjects rated the task as having been more difficult than they had expected and did higher quality work than did equitably paid subjects. However, subjects who thought the experimenter would see their ratings (Aware condition) rated it as more difficult and performed more poorly on it than those who thought she would not see them (Unaware condition). Reported task difficulty increased among overpaid subjects under aware conditions, remained stable among overpaid subjects under unaware conditions, and decreased for equitably paid subjects. These findings suggested that what appears to be “equity-restoration” may be a self-presentation strategy designed to win the experimenter's approval, and that task ratings rather than performance will be used for this purpose when they can be communicated to the experimenter. The experimenter's responsibility for the subject's pay had no effect in the present study.