Transcranial Magnetic Stimulation Elicits Coupled Neural and Hemodynamic Consequences

TLDR

Transcranial magnetic stimulation is widely used to selectively alter neural processing, yet its precise physiological effects remain uncertain. The study applied TMS to the cat visual cortex and measured both neural activity and hemodynamic responses to assess their relationship. Short TMS pulse trains produced an initial activation lasting about one minute followed by 5–10 minutes of suppression, disrupted phase relationships, and the neural changes were quantitatively coupled to hemodynamic signals across stimulation parameters, demonstrating long‑lasting neural responses that can be monitored with neuroimaging.

Abstract

Transcranial magnetic stimulation (TMS) is an increasingly common technique used to selectively modify neural processing. However, application of TMS is limited by uncertainty concerning its physiological effects. We applied TMS to the cat visual cortex and evaluated the neural and hemodynamic consequences. Short TMS pulse trains elicited initial activation (approximately 1 minute) and prolonged suppression (5 to 10 minutes) of neural responses. Furthermore, TMS disrupted the temporal structure of activity by altering phase relationships between neural signals. Despite the complexity of this response, neural changes were faithfully reflected in hemodynamic signals; quantitative coupling was present over a range of stimulation parameters. These results demonstrate long-lasting neural responses to TMS and support the use of hemodynamic-based neuroimaging to effectively monitor these changes over time.