Cortico-cortical connectivity: the road from basic neurophysiological interactions to therapeutic applications

Area of Science:

• Neuroscience
• Neurophysiology
• Brain Stimulation Techniques

Background:

• Transcranial magnetic stimulation (TMS) offers real-time evaluation of brain electrical activity.
• Dual-site TMS, inspired by Professor John Rothwell, investigates physiological interactions between brain areas by applying paired pulses.
• This method allows for testing causal effects between interconnected brain regions.

Purpose of the Study:

• To review the development and features of dual-coil TMS protocols.
• To explore the physiological role and dynamic nature of TMS-evoked pathways.
• To discuss the therapeutic implications of multi-site TMS for neurological and psychiatric conditions.

Main Methods:

• Review of dual-site TMS protocols, particularly those pioneered in Professor John Rothwell's lab.
• Investigation of short-latency interactions within the human parieto-frontal network.
• Exploration of how functional interactions vary with brain activation, condition, and timing.

Main Results:

• Discovery of a distributed system of short-latency interactions in the human parieto-frontal network, likely mediated by direct pathways.
• Demonstration that TMS-evoked pathways are dynamic and condition-dependent.
• Evidence that repeated dual-coil TMS can induce spike-time-dependent plasticity and potentiate physiological connectivity.

Conclusions:

• Dual-site TMS is a powerful tool for understanding brain connectivity and plasticity.
• Multi-site TMS can identify synaptic dysfunction markers and monitor disease progression.
• This technique holds potential for novel therapeutic strategies in neurological and psychiatric disorders by modulating brain plasticity.