Differential visual field-interhemispheric transfer: can it explain sex and handedness differences in lateralization?

Area of Science:

• Neuroscience
• Cognitive Psychology
• Human Behavior

Background:

• Hemispheric lateralization influences cognitive functions, including spatial information processing.
• Understanding visual field-hemispheric transfer is crucial for mapping brain functions and potential deficits.

Purpose of the Study:

• To investigate the directionality of spatial information transfer between cerebral hemispheres in right- and left-handed individuals.
• To determine if sex influences hemispheric transfer of spatial information.

Main Methods:

• A dot-localization task was administered to 104 participants (men and women).
• Stimuli were presented to either the left visual field of the right hemisphere (LVF-RH) or the right visual field of the left hemisphere (RVF-LH).
• The order of visual field presentation was manipulated to assess transfer effects.

Main Results:

• Right-handed subjects demonstrated significant improvement in spatial tasks when information transferred from the left hemisphere to the right hemisphere (RVF-LH to LVF-RH).
• No improvement was observed when the transfer order was reversed (LVF-RH to RVF-LH) for right-handers.
• Left-handed subjects showed no significant improvement in either transfer direction, indicating potential inhibition or lack of transfer.

Conclusions:

• Spatial information transfer to the right hemisphere is facilitated in right-handers, while transfer to the left hemisphere appears inhibited.
• Left-handed individuals may process spatial information differently, with inhibited or absent transfer in either direction.
• Findings suggest distinct neural mechanisms for functional lateralization in women and left-handers, despite observed similarities.