Understanding Magnetic Fields in Medicine

How Magnetic Fields Interact with the Brain

Electromagnetic induction, first discovered by Michael Faraday in the 19th century, is the key mechanism behind TMS. In practice, the TMS coil generates a rapidly changing magnetic field that passes through the skull without resistance. When this magnetic field reaches the brain tissue, it induces a localized electrical current. This current stimulates or inhibits neuronal activity, depending on the frequency and intensity of the magnetic pulses.

MRI and TMS: Harnessing Magnetic Fields

MRI technology is widely recognized among the general population and has proven to be a reliable and effective tool in modern medicine. It has revolutionized diagnostic imaging by providing detailed insights into the body's internal structures, particularly the brain, through the use of electromagnetic fields. Just as MRI has become a cornerstone of medical diagnostics, TMS is emerging as a powerful therapeutic tool, leveraging magnetic fields to influence brain function and treat various neurological and psychiatric conditions.

Promoting Brain Plasticity

One of the remarkable outcomes of TMS is its ability to encourage brain plasticity—the brain's natural ability to adapt and reorganize neural pathways in response to new experiences. TMS achieves this by strengthening or weakening connections in specific neural circuits, paving the way for long-term improvements in conditions like depression and anxiety. This ability to modulate neural circuits is particularly significant for patients with treatment-resistant conditions, as it provides a means to "reset" disrupted brain activity. Further discussion on neuroplasticity and its role in TMS will be explored in an upcoming chapter.

Sources:

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• Valero-Cabré, A., Amengual, J. L., et al. (2017). TMS in basic and clinical neuroscience. Neuroscientist, 23(4), 326-350. Source
• Huang, Y. Z., et al. (2005). Theta burst stimulation of the human motor cortex. Neuron, 45(2), 201-206. Source
• Barker, A. T., Jalinous, R., & Freeston, I. L. (1985). Non-invasive magnetic stimulation of the human motor cortex. The Lancet, 325(8437), 1106-1107. Source