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The Neurobiology of TMS

The Neurobiology of TMS

Written by: Dr. Sean David Vanniasingham

Principles of Transcranial Magnetic Stimulation (TMS)

In the 1800s, world-renowned English physicist Michael Faraday discovered the principles of electromagnetic induction. Fast forward to the 21st century, Faraday’s discovery was harnessed into the clinical practice of transcranial magnetic stimulation (TMS) for the treatment of mood disorders. Based on Faraday’s Law, TMS can stimulate brain neuronal circuits with tiny electrical currents induced by a changing magnetic field.


Application of TMS in Singapore 

In Singapore, the practical application of TMS is employed in the form of repetitive transcranial magnetic stimulation (rTMS). In rTMS, magnetic pulses are delivered in trains at specific frequencies. “Fast” (high frequency e.g. 10Hz) stimulation increases cortical excitability for the treatment of depression. Whereas “slow” (low frequency e.g. 1Hz) stimulation reduces cortical excitability for treating anxiety disorders. Furthermore, TMS can be targeted at focused regions of the cortex for superior precision treatment of specific conditions e.g. rTMS at 1Hz to the right orbitofrontal cortex (OFC) reduces intrusive obsessions in obsessive-compulsive disorder (OCD).

Mood disturbances such as depression are increasingly understood as disorders of connectivity in neural networks linking cortical and subcortical grey structures of the brain. Functional brain imaging has shown dysfunction in cortical regions such as the dorsolateral prefrontal cortex (DLPFC) and anterior cingulate cortex (ACC), as well as deep grey matter structures including the amygdala, nucleus accumbens, hippocampus and hypothalamus. These brain circuits are pivotal for executive functioning, regulation of emotions, reward processing and preservation of memory and cognition. They also link the nervous system to the endocrine system, which mediates the body’s response to stress. 


Neuroplasticity and TMS

Evidence suggests that TMS induces neuroplastic changes in these circuits. Neuroplasticity is the ability of the brain to reorganize itself by forming new neural connections. TMS helps readjust neurotransmitter (e.g. serotonin and dopamine) levels in a variety of brain regions. TMS also appears to exert a neuroprotective effect on the brain. Research has shown that TMS decreases brain inflammatory factors reducing oxidative stress on the brain. TMS also boosts the levels of brain-derived neurotrophic factor (BDNF), encouraging neuronal growth in regions such as the hippocampus which is vital for learning and memory. It is postulated that the anti-depressant properties of TMS may also help in normalizing the body’s neuroendocrine stress response system.


rTMS has achieved its place on international treatment guidelines as an augmentation treatment modality to be strongly considered in treatment-resistant depression. It is reported that 30-40% of depressed patients may have inadequate responses to anti-depressant medication treatment. The direct neuronal effects of rTMS may explain why rTMS may work for this group of patients. 


rTMS for OCD Treatment and other neurological disorders

In May 2022, the U.S. Food and Drug Administration (FDA) approved the use of the NeuroStar TMS system as an adjunct for treating adult patients suffering from OCD. Promising research is ongoing for the clinical application of TMS in treating Post-Traumatic Stress Disorder (PTSD), addictions, chronic pain, insomnia and many other neurological disorders.


TMS and recovery

With further advancements in TMS research and the incorporation of TMS in routine clinical practice, there is strong hope for recovery and the regaining of optimal functioning for patients afflicted by complex neuropsychiatric conditions.



1) Transcranial Magnetic Stimulation

Clinical Applications for Psychiatric Practice

2018 American Psychiatric Association Publishing, First Edition

2) The Science of Transcranial Magnetic Stimulation 

William M. Sauvé, MD; and Lawrence J. Crowther, Meng

Psychiatric Annals, Vol44, No.6, 2014

3) Repetitive transcranial magnetic stimulation increases serum brain-derived neurotrophic factor and decreases interleukin-1b and tumour necrosis factor-a in elderly patients with refractory depression 

Xiangxiang Zhao, Yanpeng Li, Qing Tian, Bingqian Zhu and Zhongxin Zhao

Journal of International Medical Research 2019, Vol. 47(5) 1848–1855

4) What is repetitive transcranial magnetic stimulation and how does it actually work?

Paul Fitzgerald, Professor of Psychiatry, Monash University

The Conversation AU, published May 13 2021

Alternative Depression Treatment: Transcranial Magnetic Stimulation

Alternative Depression Treatment: Transcranial Magnetic Stimulation

Non-Medication, FDA Approved Depression Treatment

Targeted magnetic pulses stimulate brain regions implicated in depression

Depression is a complex and nebulous beast. More than 264 million people worldwide are afflicted with the disease, and you or a loved one might be experiencing the crippling dysfunction of depression. Here’s where TMS comes in. It’s a technology which employs magnetic stimulation of brain activity to treat physiological and neurological conditions, borne out of a need to more effectively treat depression.

Over a decade ago, the United States Food and Drug Administration approved the use of transcranial magnetic stimulation to treat depression.1 Since then, TMS has become the most widely adopted method for brain stimulation, overtaking electroconvulsive therapy and deep brain stimulation. In 2012, a study demonstrated that regardless of the number of antidepressant medications that failed depressed clinical subjects, TMS delivered a consistent rate of response at 60%, and a remission rate of 40%.2 Even if you’ve been disappointed by numerous rounds of antidepressants, there is hope for you yet.

TMS delivers targeted magnetic pulses to the left dorsolateral prefrontal cortex – an area of the brain responsible for establishing positive feelings and inhibiting negative emotions generated by limbic structures such as the amygdalae. In depressed people, it is this part of the brain that shows the greatest sign of weakness or under-activity. Essentially, the precept of TMS is to stimulate neuronal activity by inducing an electric current in the prefrontal cortex.

So, you might well think of TMS as exercise for your brain – helping it achieve ‘balance’. During TMS therapy, which lasts for forty minutes a session every weekday for four to six weeks, there’s very little you actually have to do. The clinician might ask that you do some questionnaires to help him gauge the efficacy of the treatment and the extent of your depression, but that’s about it. All you have to do is sit in a chair alert and awake, and possibly make some small talk – if you are so inclined. When the electromagnetic coil fires, you’ll hear a series of clicks and there’s a small chance you may experience slight discomfort (think mild headache), but your clinician will have some aspirin ready.

As TMS is a non-invasive, non-drug therapy, you won’t have to muddle through the litany of possible side effects that come with antidepressant medication. Nor will you have to subject yourself to electroconvulsive therapy (inducing a medically controlled seizure while you’re under general anaesthesia). TMS is a remarkably well-tolerated procedure with benign side effects. In fact, it’s safer than current antidepressant medication – the seizure rate of TMS is 0.001%, compared to antidepressants’ 0.1% (a conservative estimate). You’d be a hundred times safer. Treating depression with medication is often an inexact science – trial-and-error, hit-or-miss. Drugs interact with your entire physiology. Unintended consequences and attendant side effects are part of the territory. In contrast, TMS interacts with the targeted area of your brain only, tapping into the network of its electrical circuitry. The markedly low number of side effects3 which can occur during TMS compared with drug therapy means it is a rational, sensible choice if your antidepressant medication isn’t working – there’s no need to complicate your mental health journey with another stressful round of antidepressants and their consequences.


The side effects of anti-depressants are numerous.

TMS isn’t just used to treat depression. Since the pulses can target different areas of the brain and the configuration of those pulses adjustable (scientists have discovered that modulating pulse frequencies has an effect on the change in neuronal activity), it stands to reason that it will show promise for treating other physiological or neurological conditions. In fact, TMS has catalysed a wave of clinical trials around the world that explore its efficacy in diverse disease states including autism, epilepsy, migraine, tinnitus, stroke recovery, schizophrenia, insomnia, Parkinson’s and Alzheimer’s disease.

If you’re considering TMS therapy, our experienced clinicians will work with you to formulate a holistic treatment plan with your values and goals in mind. You can discover more information about TMS therapy and if it’s a right fit for you over at the TMS Singapore website.

1More, A. (2019, August 28). Transcranial Magnetic Stimulator Industry 2019 Global Market Growth, Size, Demand, Trends, Insights and Forecast 2024. Retrieved from

2Carpenter LL, et al. (2012). Transcranial Magnetic Stimulation (TMS) for Major Depression: A Multisite, Naturalistic, Observational Study of Acute Treatment Outcomes in Clinical Practice. Depression & Anxiety 29(7):587–596.

3Janicak, P.G and Dokucu, M.E. (June 2015). Transcranial magnetic stimulation for the treatment of major depression. Neuropsychiatric Disease and Treatment. 2015:11, pp 1549-1560

NeuroStar TMS Therapy® for Depression

NeuroStar TMS Therapy® for Depression


How Does NeuroStar TMS Therapy® Work?

Transcranial magnetic stimulation (TMS) uses a targeted pulsed magnetic field, similar to what is used in an MRI (magnetic resonance imaging) machine. While the patient is awake and alert, NeuroStar TMS Therapy stimulates areas of the brain that are underactive in depression.2

NeuroStar TMS Therapy is an in-office treatment that takes 37 minutes, is performed while the patient sits in a chair, and is administered five days a week, for up to four to six weeks.

Simple steps for NeuroStar TMS Therapy:

  • Step One: The patient reclines comfortably in the treatment chair, awake and alert
  • Step Two: A small curved device containing the magnetic coil rests lightly on the patient’s head
  • Step Three: The device delivers focused magnetic stimulation directly to the target areas of the brain
  • Step Four: The patient can immediately resume normal activities

During treatment, the patient hears a clicking sound and feels a tapping sensation on the head. The most common side effect is generally mild-to-moderate pain or discomfort at or near the treatment area during the session. When this occurs it is temporary, and typically occurs only during the first week of treatment.

There are no effects on alertness or understanding; patients being treated with NeuroStar TMS Therapy can drive themselves to and from their treatment sessions. Above information is taken from:

Targeted Zaps to Treat Depression

Targeted Zaps to Treat Depression

Freedom from depression is possible through TMS treatment.

Each of us has a different genetic make-up, which is why anti-depressants may prove ineffective. Depression is a chronic mental illness that cannot be overcome simply by practicing positive thinking. For many who suffer from depression, a ‘normal life’ is often painfully out of reach. They may become more isolated and withdrawn, because it’s simply too difficult and agonising to ‘live a normal life’.

Promises Healthcare is the pioneer in providing rTMS treatment in Singapore.

rTMS stands for Repetitive Transcranial Magnetic Stimulation or repetitive magnetic brain stimulation (also called TMS). It is a non-drug alternative to anti-depressants without any of the side effects. It’s non-invasive, unlike the dated practice of electroconvulsive therapy. The treatment requires 20-30 sessions lasting 40 minutes each. During each session, around 3000 targeted magnetic pulses are delivered to the specific area of the brain that regulates moods.

It is an FDA approved treatment for depression that is proven to work – and if you are treatment-resistant (to anti-depressant medication), TMS may just be that ray of hope.

Promises Healthcare also harnesses the power of TMS to treat anxiety disorders.

For more information on the rTMS treatment, please contact our clinic.

Introducing a New Treatment for Depression: Transcranial Magnetic Stimulation

Introducing a New Treatment for Depression: Transcranial Magnetic Stimulation

Promises is the first psychiatric practice in Singapore to be able to offer Neurostar® TMS Therapy to our patients for depression treatment. Transcranial Magnetic Stimulation Therapy is one of the most technologically advanced treatments for depression available.