This region of the brain is involved in many aspects of cognition, such as reasoning, problem-solving, comprehension, and impulse control. It also happens to be a brain region that has been linked to MDD.
Prefrontal cortex dysfunction, for example, has been linked to symptoms such as rumination and suicidal ideation.
In this study, researchers used TBS to target the prefrontal cortex in youth participants for four weeks.
The researchers then used a multimodal brain mapping technique of transcranial magnetic stimulation combined with electroencephalography to observe and monitor changes in brain activity.
At the end of the four-week trial, researchers noted significant changes in brain activity at the treatment regions as well as in regions that were not directly stimulated with TBS.
Changes in brain activity were also associated with a reduction in depressive and rumination scores.
More treatment options needed, "Major Depressive Disorder affects approximately 11 per cent of adolescents and youth but existing treatments, such as medication and/or psychotherapy, fail to significantly improve symptoms in about 30 - 50 per cent of cases," says Farzan, a professor in SFU's School of Mechatronic Systems Engineering (MSE).
She also holds the chair in Technology Innovations for Youth Addiction Recovery and Mental Health and heads SFU's new eBrain Lab.
Researchers note that some medications have also been associated with side effects in youth such as suicidal thoughts and behaviours - leading to the search for safer treatment options.
Building on previous research: Previous research has shown a link between dysfunction of the prefrontal cortex and MDD.
"Using TMS-EEG brain mapping technology, we also found that the prefrontal cortex in youth with MDD exhibited greater brain activity relative to healthy youth.”
“It was very interesting to see in the current study that four weeks of TBS treatment seemed to reduce this excessive brain activity, possibly reflecting a return to a 'healthy' state," says SFU doctoral student Prabhjot Dhami, the study's first author.
Prefrontal cortex impairments in youth with MDD may also contribute to symptoms such as rumination and suicidal ideation/behaviour, Farzan notes.
Since the prefrontal cortex is critical for executive functioning, dysfunction or deficits in this region can lead to the onset and maintenance of depressive symptoms.
The researchers say neurotechnological treatments, such as the combination of TBS targeted to the prefrontal cortex, followed by a cognitive exercise that may also engage this brain area, have the potential to optimise the impact on the prefrontal cortex in youth MDD to alleviate symptoms more effectively.