Brain stimulation and imaging in children with ADHD.


Attention Deficit/Hyperactivity Disorder (ADHD) is a common condition affecting Canadian children. It can have significant negative long-term outcomes when it is not effectively treated. Current treatments (such as stimulant medication) can be effective, but don't work for everyone and can have significant side effects. These treatments work on specific neurotransmitters in the brain (dopamine and noradrenaline) and we know that ADHD has a large genetic component. However, we do not fully understand how these neurotransmitter dysfunctions cause ADHD symptoms.

TMS is a non-invasive way of affecting brain functioning in a specific area and has been used to investigate brain excitability. It has also been used in the treatment of depression and anxiety in adults. For this study participants will receive only one session, which can result in a change in excitability for 30-60min i.e. is not long lasting.

To examine how neurotransmitters relate to specific symptoms in ADHD we will use advance MRI techniques that can show both structure, function and dopamine production in the brain. We will then have participants complete executive function cognitive tasks to measure their abilities to control their behaviour and attention. Participants will then receive transcranial magnetic stimulation (TMS) to an area of the brain associated with attention.

In this project we hope to better characterize the role of dopamine in children with ADHD through the use of a novel neuroimaging technique (neuromelanin-MRI). We then want to determine the excitability of different cortical targets using safe, non-invasive brain stimulation and behavioural measures. Together this will further the understanding of the neurobiology in pediatric ADHD and help determine how to better personalize treatments for this population going forward.


Currently recruiting participants: Yes

Eligible gender: Male, Female, Transgender, Other

Eligible ages: 10 to 16

Accepts healthy participants: Yes

Inclusion criteria:

We are recruiting participants with and without ADHD.

Inclusion Criteria (for participants with and without ADHD):
(1) age 10-16 years

Inclusion Criteria (for participants with ADHD):
(1) diagnosis of ADHD confirmed by a qualified medical professional,
(2) receiving treatment consisting of a single stimulant medication for the past 3 months at a consistent type and dose
(3) persistent symptoms while on stimulant medication

Exclusion criteria:

Exclusion Criteria (for participants with and without ADHD):
(1) other psychoactive medications (aside from stimulant medication in ADHD group)
(2) Impediments to TMS or MRI (i.e., metal implants in body);
(3) Prior electroconvulsive therapy or vagus nerve stimulation;
(4) Prior diagnosis of other chronic neurologic disease or brain injury, mania, psychosis, autism or bipolar disorder
(5) unable to understand instructions in English.

Exclusion Criteria (for participants without ADHD):
(1) diagnosis of any neurodevelopmental condition (ADHD, Autism, intellectual disability).


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Additional information

Contact information

Participants can contact research team through email or phone.

Principal investigator:

Kara Murias

Clinical trial: