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Choice reaction time performance correlates with diffusion anisotropy in white matter pathways supporting
David S Tuch1, David H Salat, Jonathan J Wisco
1Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, 149 13th Street, Room 2301, Charlestown, MA 02129, USA. dtuch@nmr.mgh.harvard.edu
Summary
Individual differences in reaction time (RT) are linked to white matter (WM) properties. This study found correlations between fractional anisotropy (FA) in specific WM pathways and visual choice reaction time (CRT) performance.
Area of Science:
- Neuroscience
- Neuroimaging
- Human Behavior
Background:
- Human reaction time (RT) shows significant interindividual variability.
- The neural mechanisms driving this variability, particularly in white matter (WM) pathways, are not well understood.
- Previous research has not demonstrated a link between WM physiological properties and RT in healthy adults' cortical pathways.
Purpose of the Study:
- To investigate the relationship between white matter (WM) integrity and behavioral reaction time (RT) variability.
- To determine if diffusion tensor fractional anisotropy (FA) in specific WM pathways correlates with performance on a visual self-paced choice RT (CRT) task.
- To explore the neural underpinnings of individual differences in visuospatial attention and reaction time.
Main Methods:
- Diffusion tensor MRI (DTI) was used to measure white matter (WM) properties.
- Fractional anisotropy (FA), a measure of water diffusion coherence, was calculated.
- FA values were correlated with performance on a visual self-paced choice reaction time (CRT) task.
Main Results:
- Choice reaction time (CRT) performance significantly correlated with FA in WM pathways crucial for visuospatial attention, including the right optic radiation, right posterior thalamus, and right medial precuneus.
- Additional correlations were found in the left superior temporal sulcus WM and left parietal operculum.
- The observed correlations were predominantly in visual and parietal WM pathways, not motor or interhemispheric pathways, suggesting a link to the visuospatial attention network.
Conclusions:
- Individual differences in visual choice reaction time (CRT) performance are associated with variations in white matter (WM) integrity within the visuospatial attention network.
- The findings highlight the role of specific WM pathways, particularly in the right hemisphere, in modulating reaction time.
- This study provides evidence that WM physiological properties in visual and parietal pathways, rather than motor pathways, underlie interindividual variability in reaction time.