Transient destabilization of interhemispheric functional connectivity induced by spreading depolarization

Area of Science:

• Neuroscience
• Systems Neuroscience
• Computational Neuroscience

Background:

• Cortical spreading depolarization (CSD) is a key response to brain insults and a mechanism in migraine aura.
• The impact of CSD on brain network activity remains poorly understood.

Purpose of the Study:

• To investigate the dynamics of cross-hemispheric functional connectivity during unilateral CSD in rats.
• To explore the role of inhibitory transmission in CSD-associated connectivity changes.

Main Methods:

• Utilized undirected (mutual information) and directed (transfer entropy) measures to analyze brain network connectivity.
• Studied unilateral CSD development in freely behaving rats.
• Administered a GABA receptor antagonist (penthylenetetrazole) to modulate cortical inhibition.

Main Results:

• CSD onset led to a transient loss of undirected functional connectivity between hemispheres.
• Following CSD, directed connectivity analysis revealed an increased influence from the unaffected hemisphere to the affected one.
• Mild cortical disinhibition did not alter CSD but attenuated or abolished CSD-induced connectivity alterations.

Conclusions:

• CSD induces significant, transient changes in inter-hemispheric functional connectivity.
• Inhibitory transmission plays a crucial role in modulating these CSD-related network effects.
• CSD-induced connectivity changes may represent a potential network biomarker for CSD in clinical settings.