Handedness and White Matter Networks

Area of Science:

• Neuroscience
• Human Motor Behavior
• Brain Imaging

Background:

• Human motor behavior is characterized by laterality, most notably hand preference.
• The neural underpinnings of handedness, or asymmetrical hand use, remain incompletely understood despite extensive research.
• Advances in neuroimaging offer new ways to investigate the brain structures associated with handedness.

Purpose of the Study:

• To review the current understanding of the neural basis of handedness.
• To explore how white matter structural connectivity relates to handedness.
• To identify future research directions in handedness and neuroanatomy.

Main Methods:

• Review of existing literature on handedness and neuroimaging.
• Focus on diffusion magnetic resonance imaging (dMRI) studies.
• Analysis of white matter pathways, including intrahemispheric and interhemispheric tracts.

Main Results:

• Structural connectivity of white matter differs between left- and right-handers.
• Handedness is associated with asymmetries in intrahemispheric pathways (e.g., superior longitudinal fasciculus) crucial for visuomotor and visuospatial functions.
• Variability in the corpus callosum's structure is linked to handedness, but projection tracts for motor execution (corticospinal tract) show less clear associations.

Conclusions:

• White matter structural connectivity provides insights into the neural basis of handedness.
• Specific pathways involved in sensory-motor integration and visuospatial processing appear more relevant to handedness than direct motor execution pathways.
• Further neuroscientific and genetic research is needed to fully elucidate the complexities of handedness.