A study of epilepsy patients with implanted electrodes provides an unprecedented view of the changes in brain activity created by electrical stimulation.
These findings, published in Journal of Neuroscience, have the potential to improve noninvasive stimulation approaches toward the treatment of neuropsychiatric disorders.
Repetitive transcranial magnetic stimulation (rTMS) is increasingly used in patients with disorders such as depression that do not respond well to medication or psychotherapy.
Although the effects of stimulation on the motor cortex have been characterized in animal models and humans, its effects on other brain areas — including the prefrontal cortex, the target of rTMS in depression — are unclear.
Corey Keller and colleagues mimicked rTMS of the prefrontal cortex in four epileptic patients who were previously implanted with brain electrodes to manage their condition.
This allowed the researchers to study changes in the neural activity of specific regions with a resolution that is not possible with noninvasive brain stimulation and imaging.
Baseline excitability can predict regions of change following stimulation. Left panel: Single subject baseline excitability. Middle: Regions of change after 10Hz stimulation. Right: Example of brain dynamics during and after 10Hz stimulation (arrowhead). image is credited to Corey Keller.
Comparing participants’ brain excitability before and after the rTMS treatment, the team found that they were able to accurately predict which brain regions would be affected by the stimulation. This research could inform the development of individualized stimulation protocols.
Funding: The study was financed by the NIH/National Institute of Neurological Disorders and Stroke.
Source: David Barnstone – SfN
Image Source: Corey Keller.
Original Research: Abstract for “Induction and quantification of excitability changes in human cortical networks” by Corey J. Keller, Yuhao Huang, Jose L. Herrero, Maria Fini, Victor Du, Fred A. Lado, Christopher J. Honey and Ashesh D. Mehta in Journal of Neuroscience. Published May 21 2018.
doi:10.1523/JNEUROSCI.1088-17.2018
