Summary: Deep brain stimulation applied to a small brain area associated with reward and motivation resulted in brain metabolic changes over 12 months after implantation and alleviated some symptoms of depression in people with treatment-resistant depression.
Source: UT Houston
Deep brain stimulation (DBS) of the superolateral branch of the medial forebrain bundle (MFB), which is related to reward and motivation, revealed brain metabolic changes over 12 months after DBS implantation, which which makes it a strong potential therapy for treatment-resistant depression according to researchers at UTHealth Houston.
The results of the study, which included 10 patients, were published today in Molecular psychiatry.
“It’s something people have been trying to do for a long time, but we haven’t always had great success using DBS for psychiatric illnesses,” said first author Christopher Conner, MD, Ph. .D., former neurosurgical resident in the Vivian L. Smith Department of Neurosurgery at McGovern Medical School at UTHealth Houston.
“But this PET study shows that we are changing how the brain works in the long term and we are starting to change the way the brain starts to organize itself and process information and data.” Conner is currently a Fellow at the University of Toronto.
For years, DBS has been used to treat patients with movement disorders such as Parkinson’s disease, tremors and dystonia, and studied as a possible treatment for patients with treatment-resistant depression. In DBS, electrodes are implanted in certain areas of the brain, where they generate electrical impulses to affect brain activity.
However, finding which part of the brain should be targeted to treat long-term depression has been difficult.
“We targeted a bundle of fibers that leave this small area of the brainstem to travel to other areas of the brain,” Conner said.
“The PET scans indicated that this small target area has very diffuse downstream effects. This is not a one-size-fits-all effect as there is no single area of the brain linked to depression. The whole brain needs to be changed and thanks to this little target, that’s what we were able to do.
The researchers performed an initial PET scan before the DBS procedure on the 10 study patients for a baseline image. They performed additional PET scans at six and 12 months to assess changes after treatment. The scans of 8 of the 10 patients showed a response.
“A responder to treatment means that your depression potentially decreases by at least 50%; you feel much better,” said co-author João de Quevedo, MD, Ph.D., professor in the Louis A. Faillace, MD, Department of Psychiatry and Behavioral Sciences at McGovern Medical School.
“So for patients with treatment-resistant severe chronic depression, halving our symptoms is a lot. It’s the difference between being disabled and being able to do something. Correlated with PET image changes, our patients reported that their depression decreased after treatment.” De Quevedo is also director of the Translational Psychiatry Program and the Treatment-Resistant Depression Program, part of the Mood Disorders Center of Excellence.
About This Depression and DBS Research News
Author: Press office
Source: UT Houston
Contact: Press Office – UT Houston
Image: Image is in public domain
Original research: Access closed.
“Metabolic brain changes and clinical response to deep brain stimulation of the superolateral forebrain medial bundle for treatment-resistant depression” by Christopher R. Conner et al. Molecular psychiatry
Brain metabolic changes and clinical response to superolateral forebrain medial bundle deep brain stimulation for treatment-resistant depression
Deep brain stimulation (DBS) of the superolateral branch of the medial forebrain bundle is an effective therapy for treatment-resistant depression, providing rapid antidepressant effects. In this study, we use 18F-fluorodeoxyglucose positron emission tomography (PET) to identify brain metabolic changes over 12 months after DBS implantation in ten of our patients, compared to baseline.
The primary outcome was a 50% reduction in the Montgomery-Åsberg Depression Rating Scale (MADRS) score, which was interpreted as a response. Deterministic fiber tracking was used to individually map the target area; Probabilistic tractography was used to identify modulated fiber bundles modeled using cathodic contacts.
Eight of the ten patients included in this study were responders. PET imaging revealed significant decreases in bilateral metabolism of the caudate, mediodorsal thalamus, and dorsal anterior cingulate cortex that were evident at 6 months and continued through 12 months after surgery.
At 12 months after surgery, significant left ventral prefrontal cortical metabolic decreases were also observed. The right caudal metabolic decrease at 12 months was significantly correlated with the mean reduction in MADRS. Probabilistic tractography modeling revealed that such metabolic changes were along cortico-limbic nodes structurally connected to the DBS target site.
Such metabolic changes observed after DBS correlated with clinical response provide insights into how future studies can elaborate such data to create biomarkers to predict response, the development of which will likely require multimodal imaging analysis.
Deep brain stimulation of brain area related to reward and motivation is a potential therapy for depression – Neuroscience News