Attention, Not Performance, Correlates With Afterdischarge Termination During Cortical Stimulation.

Area of Science:

• Neuroscience
• Cognitive Science
• Neurophysiology

Background:

• Cortical stimulation is a century-old brain mapping technique.
• A common assumption is that stimulation effects are localized.
• Afterdischarges from stimulation can cause seizures and interfere with functional localization.

Purpose of the Study:

• To investigate if afterdischarge termination can precede cognitive task performance.
• To explore the spatiotemporal dynamics of brain activity during cognitive task-induced afterdischarge termination.
• To challenge the assumption of localized effects in cortical stimulation and brain mapping.

Main Methods:

• Utilized electrocorticography (ECoG) to monitor brain activity.
• Applied cortical stimulation and induced afterdischarges.
• Assessed the timing of afterdischarge termination relative to cognitive task execution.
• Analyzed widespread cortical changes during afterdischarge termination.

Main Results:

• Afterdischarge termination was observed to occur before overt cognitive task performance.
• Electrocorticography revealed widespread cortical changes, not limited to stimulation or task-relevant sites.
• Thresholds for afterdischarges and functional responses varied across stimulation trials.
• Task-related brain changes were found to be diffuse in location and extended in time.

Conclusions:

• Task-related brain activity influencing performance is not restricted to specific functional regions or networks.
• Brain activity affecting task execution can be diffuse and extended in time, challenging localized models.
• Fluctuations in attention, engagement, or motivation may contribute to these widespread brain effects.
• Understanding diffuse and temporally extended brain activity is crucial for accurate brain mapping and interpreting clinical behaviors.