Axono-cortical evoked potentials: A proof-of-concept study

Area of Science:

• Neurosurgery
• Neurophysiology
• Cognitive Neuroscience

Background:

• Awake surgery is optimal for precise tumor removal based on functional areas.
• The precise mechanisms of how electrical stimulation affects brain function are not fully understood.
• Investigating direct electrical stimulation of white matter pathways is crucial for understanding brain connectivity.

Observation:

• A novel technique was used to explore signal propagation from white matter pathways to cortical sites.
• During awake surgery for a left ventral premotor cortex cavernoma, 60Hz stimulation of opercular white matter induced anomia.

Findings:

• Stimulating the same white matter site at 1Hz allowed recording of axono-cortical evoked potentials (ACEPs) in Broca's area and the central sulcus.
• ACEPs were obtained by averaging time-locked unitary responses, providing insights into signal propagation.

Implications:

• This method offers a new way to investigate the functional connectivity of white matter tracts during neurosurgical procedures.
• Findings contribute to a better understanding of the neural mechanisms underlying speech arrest induced by white matter stimulation.