Local polymorphic delta activity in cortical lesions causes global decreases in functional connectivity

Area of Science:

• Neuroscience
• Computational Neuroscience
• Brain Network Dynamics

Background:

• Local brain lesions often lead to global network changes attributed to disconnection.
• However, damaged areas may retain altered neural activity, a factor less explored in network models.

Purpose of the Study:

• To investigate if altered local neural activity, specifically polymorphic delta activity (PDA), can explain global functional connectivity decreases observed in patients with brain lesions.
• To model the impact of PDA and structural disconnection on brain network function.

Main Methods:

• Simulated human brain activity using a network of 78 coupled neural masses based on the structural connectome.
• Introduced lesions by simulating PDA, weakening structural connections, or deleting connections to mimic focal damage, tumors, or resection.

Main Results:

• Simulated PDA alone, independent of structural disconnection, significantly decreased global functional connectivity.
• Altered functional connectivity was observed even in regions not directly lesioned, with PDA's impact varying based on the lesioned area's network properties.

Conclusions:

• Locally disturbed neural activity (PDA) is a key mechanism driving global functional connectivity changes after brain lesions, even without structural disconnection.
• The effects of focal brain lesions extend beyond the damaged area, influencing the entire brain network and necessitating a holistic network perspective.