Characterization and validation of a neuronavigated robotic system for two transcranial magnetic stimulation stimulators

• Grant number: 24/14104-7
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: September 01, 2024
• End date: July 31, 2025
• Field of knowledge: Physical Sciences and Mathematics - Physics
• Principal Investigator: Oswaldo Baffa Filho
• Grantee: Ana Carolina de Paula Cavalheri
• Host Institution: Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (FFCLRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
• Associated research grant: 13/07699-0 - Research, Innovation and Dissemination Center for Neuromathematics - NeuroMat, AP.CEPID

Abstract

Transcranial magnetic stimulation, or TMS, is a non-invasive method of brain stimulation where an intense magnetic field that varies rapidly over time induces an electrical field capable of depolarizing cortical neurons and evoking action potentials, stimulating a cerebral target. Among its applications, motor mapping stands out, a technique in which the pulses are applied to the primary motor cortex and the area of muscle representation on the cortical surface is delimited. Generally, mapping is performed with the application of single pulses (pTMS). However, the use of paired pulses (ppTMS) has been shown to be more efficient in cases of motor impairment. In ppTMS, pulses are delivered with controlled intensity and latency. Depending on the temporal interval between them, the phenomena of inhibition (SICI, short interval cortical inhibition) or intracortical facilitation (ICF) can be observed. The application of contralateral paired pulses (dual site TMS) also allows studies on brain connectivity and new possibilities regarding motor mapping. Therefore, this project proposes the improvement and characterization of a system with two robots integrated with neuronavigation for the positioning of two TMS stimulators, which allows experiments to be carried out with contralateral paired pulses with controlled latency. It is essential that the pulses are applied to the primary motor cortex and that the system assures the appropriate time interval between pulses, as millisecond differences between stimuli evoke different responses.