Opportunities and obstacles in non-invasive brain stimulation

Area of Science:

• Neuroscience
• Biomedical Engineering

Background:

• Non-invasive brain stimulation (NIBS) is a rapidly evolving field with potential for widespread clinical application.
• Understanding the mechanisms of different NIBS modalities is crucial for optimizing therapeutic efficacy.

Purpose of the Study:

• To review the mechanisms of four distinct non-invasive brain stimulation techniques: electrical, magnetic, light, and ultrasound.
• To discuss the challenges and opportunities in advancing NIBS research and application.

Main Methods:

• Review of existing literature on the mechanisms of electrical, magnetic, light, and ultrasound brain stimulation.
• Analysis of the complexities of brain activity (stochastic and deterministic) and their impact on NIBS.
• Identification of key challenges including inter-individual variability, dose-response relationships, bias, and neuroanatomical heterogeneity.

Main Results:

• Detailed examination of the four primary NIBS modalities and their underlying principles.
• Discussion of how the complex nature of brain activity influences NIBS efficacy.
• Highlighting significant challenges that currently limit the precision and effectiveness of NIBS.

Conclusions:

• NIBS holds significant promise for accessible brain modulation.
• Addressing challenges in variability, targeting, bias, and sample size is critical for future progress.
• Five key areas for future research include closed-loop systems, consistent targeting, bias reduction, multimodal approaches, and strategies for small sample sizes.