The need for hemispheric separation in pairwise structural disconnection studies

Area of Science:

• Neuroscience
• Computational Neuroscience
• Brain Imaging

Background:

• Recent advances enable indirect measurement of the structural disconnectome.
• Studies often combine left and right hemispheric lesion data for behavioral analysis.
• Hemisphere-specific analyses are underutilized.

Purpose of the Study:

• To compare the effectiveness of joint versus separate hemispheric analyses in identifying true structural disconnections.
• To determine the optimal analytical approach for studying pairwise structural disconnections after brain damage.

Main Methods:

• A simulation study was conducted to model brain damage and connectivity.
• Analyses were performed both jointly (combining hemispheres) and separately (by hemisphere).
• Statistical power and significance thresholds were evaluated for both approaches.

Main Results:

• Joint and separate analyses yielded distinct disconnection patterns.
• Joint analyses exhibited a bias against detecting intra-hemispheric disconnections.
• Intra-hemispheric connections were statistically underpowered and less likely to reach significance in joint analyses.

Conclusions:

• Joint analysis of left and right hemispheric lesions introduces bias, underestimating intra-hemispheric disconnections.
• Hemisphere-specific analyses are crucial for accurately mapping structural disconnections.
• Future research on pairwise structural disconnections should prioritize separate analyses by hemisphere.