According to the disconnection hypothesis of cognitive aging, cognitive deficits associated with brain aging could be a result of damage to connective fibres. It has been suggested that the age-related decline in cognitive abilities is accompanied by age-related changes in interhemispheric communication ensured by commissural fibres. This study aimed to contribute to this topic by investigating the effects of aging on the efficiency of interhemispheric transfer of tactile information. A total of 168 right-handed subjects, aged 20-90 years, have been tested using the fingertip cross-localization task: the subject must respond to a tactile stimulus presented to one hand using the ipsilateral (uncrossed condition) or contralateral hand (crossed condition). Because the crossed task requires interhemispheric transfer of information, the value of the difference between the uncrossed and crossed conditions (CUD) can be deemed to be a reliable measure of the efficiency of the interhemispheric interactions. The uncrossed condition was more accurate than the crossed condition for all ages. However, the degree of the CUD was significantly age-dependent. The effectiveness of the interhemispheric transfer of tactile information decreased significantly with age and may indicate the occurrence of age-related changes of the corpus callosum. Considerably, performance appears to decline around the seventh decade of life with the fastest decline in the subsequent decades. The results suggest a relationship between brain aging and the efficiency of the interhemispheric transfer of tactile information. The findings are discussed in relation to the strategic role of white matter integrity in preserving behavioural performances.
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http://dx.doi.org/10.1016/j.jocn.2020.05.035 | DOI Listing |
Neurosci Biobehav Rev
December 2024
School of Psychology, University of Leeds, Leeds LS2 9JT, UK.
The corpus callosum plays a critical role in inter-hemispheric communication by coordinating the transfer of sensory, motor, cognitive, and emotional information between the two hemispheres. However, as part of the normal aging process, the corpus callosum undergoes significant structural changes, including reductions in both its size and microstructural integrity. These age-related alterations can profoundly impact the brain's ability to coordinate functions across hemispheres, leading to a decline in various aspects of sensory processing, motor coordination, cognitive functioning, and emotional regulation.
View Article and Find Full Text PDFJ Clin Med
November 2024
Department of Radiology, School of Medicine, South Lake Union Campus, University of Washington, 850 Republican St., Seattle, WA 98109, USA.
The fundamental question of normal brain myelination in human is still poorly understood. : Age-dependent global, regional, and interhemispheric sex-related differences in brain myelination of 42 (19 men, 23 women) healthy adults (19-67 years) were explored using the MRI method of fast macromolecular fraction (MPF) mapping. : Higher brain myelination in males compared to females was found in global white matter (WM), most WM tracts, juxtacortical WM regions, and putamen.
View Article and Find Full Text PDFFront Hum Neurosci
October 2024
Department of Psychiatry and Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, Los Angeles, CA, United States.
Introduction: Neuroimaging has expanded our understanding of pediatric brain disorders in which white matter organization and connectivity are crucial to functioning. Paralleling the known pathobiology of many neurodevelopmental disorders, traumatic brain injury (TBI) in childhood can alter trajectories of brain development. Specifically, diffusion tensor imaging (DTI) studies in TBI have demonstrated white matter (WM) abnormalities that suggest microstructural disruptions that may underlie atypical neurodevelopment.
View Article and Find Full Text PDFNeuropsychology
November 2024
Department of Psychology, University of Houston.
eNeuro
November 2024
Department of Molecular and Cellular Biology and Center for Brain Science, Harvard University, Cambridge, Massachusetts 02138
Each olfactory cortical hemisphere receives ipsilateral odor information directly from the olfactory bulb and contralateral information indirectly from the other cortical hemisphere. Since neural projections to the olfactory cortex (OC) are disordered and nontopographic, spatial information cannot be used to align projections from the two sides like in the visual cortex. Therefore, how bilateral information is integrated in individual cortical neurons is unknown.
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