Intra- and inter-hemispheric network dynamics supporting object recognition and speech production.

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Systems Neuroscience

Background:

• Understanding the neural basis of object recognition and speech production is crucial for cognitive neuroscience.
• Existing brain models often lack millisecond-scale temporal resolution of white matter connectivity dynamics.

Purpose of the Study:

• To construct normative brain atlases detailing intra- and inter-hemispheric white matter connectivity dynamics.
• To visualize functional connectivity modulations supporting object recognition and speech production at high temporal resolution.

Main Methods:

• Quantified electrocorticographic (ECoG) high-gamma activity from 1,114 intracranial electrodes during naming tasks.
• Utilized diffusion-weighted imaging tractography to identify direct white matter streamlines between electrode sites.
• Defined functional connectivity as simultaneous, naming-related high-gamma modulations at connected sites.

Main Results:

• Identified immediate, modality-specific connectivity enhancements post-stimulus onset.
• Observed posterior-to-anterior propagation of left intra-hemispheric connectivity during response preparation.
• Detailed task-specific connectivity patterns for picture naming, environmental sound naming, and auditory descriptive naming.
• Highlighted common network enhancements for perceptual processing, semantic/lexical access, and overt speech.

Conclusions:

• The developed brain atlases provide millisecond-scale insights into white matter connectivity supporting object recognition and speech production.
• These findings enhance current models by incorporating dynamic neural pathways.
• The study elucidates the role of both intra- and inter-hemispheric connectivity in complex cognitive functions.