Can transcranial electric stimulation with multiple electrodes reach deep targets?

Area of Science:

• Neuroscience
• Biomedical Engineering
• Medical Physics

Background:

• Transcranial electric stimulation (TES) is typically limited to superficial cortical targets.
• Reaching deep brain structures with TES is challenging due to current dissipation through the scalp and cortex.
• Novel methods propose interfering waveforms or pulsed stimulation for deeper brain access.

Purpose of the Study:

• To investigate if conventional multi-electrode TES can achieve focal deep brain stimulation.
• To determine if optimized conventional TES is comparable to newer stimulation techniques.
• To explore the role of cerebrospinal fluid in guiding currents to deep brain targets.

Main Methods:

• Numerical optimization of multi-electrode configurations for conventional TES.
• Utilizing a detailed and realistic head model for current flow simulations.
• Analyzing current intensity and focality at deep brain target locations.

Main Results:

• Optimized conventional multi-electrode TES can effectively stimulate deep brain targets.
• The proposed method demonstrates comparable or superior performance to novel stimulation approaches.
• Cerebrospinal fluid plays a significant role in channeling currents towards deep brain structures.

Conclusions:

• Conventional TES, when optimized, is a viable method for deep brain stimulation.
• Multi-electrode optimization offers a practical approach to enhance focality and intensity in deep brain targeting.
• Understanding current dynamics, including the influence of cerebrospinal fluid, is crucial for effective TES.