Binding of cortical functional modules by synchronous high-frequency oscillations.

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Electrophysiology

Background:

• The role of high-frequency phase-locked oscillations in integrating information across cortical areas remains debated.
• Understanding neural mechanisms of information binding is crucial for cognitive neuroscience.

Purpose of the Study:

• To investigate the involvement of cortico-cortical co-ripples in information binding during cognitive tasks.
• To determine the timing, location, and characteristics of co-ripples during reading and semantic decisions.

Main Methods:

• Intracranial electroencephalography (iEEG) was used to record brain activity.
• Analysis focused on ~90 Hz oscillations (co-ripples) and their synchronization across cortical areas.
• Non-oscillatory high gamma activity was used as a control for general co-activation.

Main Results:

• Cortico-cortical co-ripples significantly increased during reading and semantic decision tasks.
• Fusiform wordform areas co-rippled with language areas, peaking 200-400 ms post-word onset.
• Co-ripples were phase-locked over long distances (>12 cm), suggesting widespread integration.
• Co-activation (high gamma) preceded co-ripple activity.

Conclusions:

• Widespread synchronous cortico-cortical co-ripples may play a key role in integrating information across distributed brain networks.
• These oscillations appear to support sustained cognitive processes like reading and semantic processing.
• The findings provide evidence for a specific neural mechanism underlying information binding in the human brain.