2: Safety assessment of transcranial radio frequency stimulation for non-invasive brain stimulation

Abstract: The world health organization (WHO) estimates that one out of three people worldwide suffer from neurological disorders, many of which deal with drug-resistant conditions. Brain stimulation techniques have shown great merit in the treatment of many of those patients. Among them, non-invasive brain stimulation (NIBS) techniques are of particularly high value as, when effective, they can potentially prevent invasive procedures. Some of the established NIBS methods, e.g. transcranial electrical stimulation, transcranial magnetic stimulation, and transcranial focused ultrasound stimulation, are now widely used in clinical practice, including rehabilitation and treatment of mental disease. Each of these methods carry associated benefits and limitations. Therefore, the search for novel approaches to non-invasively modulate neural activity, providing a wider range of possible treatments for future clinical applications, is of great interest to the scientific community. Recently, our lab introduced transcranial radiofrequency stimulation (TRFS), a novel and innovative NIBS method. We have demonstrated its efficacy in modulating ongoing neural activity through in vivo proof-of-concept studies in mice. Whereas TRFS has shown promise as a therapeutic neuromodulation technique, evaluation of its safety profile warrants scientific exploration. In this study, we assessed the neurobiological safety of this method in murine models. Wild type male and female mice were randomly assigned to either the control group, or the RF stimulation group. After the stimulation, mice were euthanized and their brain tissues were harvested. Immunohistochemical analysis was performed using IBA1, GFAP, and Caspase 3 antibodies to look for neuroinflammation, microglial activity, astrocyte reactivity, and apoptosis. Quantitative analysis was performed using FIJI and custom MATLAB code to evaluate neurological expression and perform statistical comparison between groups.