Interhemispheric interaction during childhood: I. Neurologically intact children.
ABSTRACT This study examined the development of interaction between the hemispheres as a function of computational complexity (Banich & Belger, 1990; Belger & Banich, 1992) in 24 children aged 6.5 to 14 years. Participants performed 2 tasks: a less complex physical-identity task and a more complex name-identity task. Children, like adults, exhibit an across-hemisphere advantage on the computationally more complex name-identity task, and neither a within-nor an across-hemisphere advantage for the computationally less complex physical-identity task. Correlations indicated that the younger the child, (a) the greater the size of the within-hemisphere advantage on the less complex task, (b) the greater the size of the across-hemisphere advantage on the more complex task, and (c) the poorer the ability to ignore attentionally distracting information in a selective attention paradigm. These results suggest that interhemispheric interaction in children, like that in adults, serves to deal with the heightened processing demands imposed by increased computational complexity.
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ABSTRACT: Corpus callosum (CC) is the main white matter commissure between the two cerebral hemispheres. Abnormalities of CC have been shown in schizophrenia patients by magnetic resonance imaging (MRI) studies. We here further investigated CC organization with diffusion imaging (DWI) in a sample of schizophrenia patients recruited from the epidemiologically defined catchment area of South Verona, Italy. Sixty-seven patients with schizophrenia and 70 normal controls were studied. Regions of interests (ROIs), standardized at 5 pixels, were placed in CC on the non-diffusion weighted echoplanar images (b = 0) and were then automatically transferred to the corresponding maps to obtain the apparent diffusion coefficient (ADC) of water molecules. ADC measures for all callosal subregions in schizophrenia patients were significantly greater compared to normal controls (ANCOVA, p < 0.05). Positive symptoms significantly correlated with anterior callosal ADC measures (partial correlation analyses, p < 0.05). These findings support the existence of widespread microstructure disruption of CC in schizophrenia, which may ultimately lead to inter-hemispheric misconnection, and also suggest a specific role of anterior transcallosal disconnectivity in underlying positive symptoms. Future longitudinal MRI studies in high risk and first-episode patients together with neurophysiological tests are indicated to further examine CC anatomical abnormalities and inter-hemispheric transmission in schizophrenia.Schizophrenia Research 11/2005; 79(2-3):201-10. · 4.59 Impact Factor
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ABSTRACT: Many studied reported that working memory components receive remarkable changes during lifespan. In order to better investigate this, we evaluated working memory components on human subjects belonging to ﬁve groups (10 subjects each) at different ages 6, 8 and 10 years old, young adult (age) and old adult (age). Our pattern of results shows a major transition in object sequence manipulation performance between ages 8 and 10 years. If related to young adults results, both 10-year- old children and old adults differed in accuracy and RT in both maintenance and manipulation conditions. In particular, young adults and old adults differ in RTs in the manipulation condition. Our results also suggest that a change in response strategy from 6 to 8 years of age, to prioritize accuracy may be present. Our ﬁndings appear consistent with recent neuroscientiﬁc ﬁndings, and lead to novel predictions.Neurological Sciences 06/2014; · 1.41 Impact Factor
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ABSTRACT: The goal of the present study was to determine whether a reduced capacity for interhemispheric integration can explain the attention deficits seen in psychopathic individuals under conditions that place substantial demands on left-hemisphere-specific resources. The present study examined the performance of 54 incarcerated psychopathic and nonpsychopathic male offenders on a same-different global-local paradigm that permits manipulation of both the magnitude of processing demands and the demand for interhemispheric coordination. Prior studies with similar paradigms have demonstrated that the cerebral hemispheres can function more efficiently as relatively independent processors on simple tasks, whereas communication between the hemispheres improves performance when processing demands are heavy. Analyses indicated that psychopathic offenders are not deficient in interhemispheric integration but provided additional evidence consistent with the left hemisphere activation hypothesis of psychopathy.Neuropsychology 02/2007; 21(1):82-93. · 3.58 Impact Factor