HBP scientists have developed personalised brain models to improve the treatment of depression

Deep Brain Stimulation (DBS) is an invasive procedure carried out to treat patients with neurological and psychiatric conditions who are resistant to other forms of treatment. Electrodes are inserted into the brain and targeted pulses of electrical current are administered to patients. Generic brain stimulation models have been previously developed for Parkinson's disease, but this is the first time researchers have used this approach to model the response to DBS of patients with depression.

Despite improvements in the surgery and electrode placement, DBS in treatment-resistant depression currently has a success rate of approximately 50%. “The design space for DBS treatment is often very big, with many variables to consider. Treatments involve adjustment of the stimulation parameters over time and then waiting to see if the symptoms improve,” explains Jan Fousek from the Institut de Neurosciences des Systèmes in Marseille (INS), one of the authors of the study. “Modelling a virtual brain, tailored to each patient, that simulates their response to DBS could improve the efficacy of the procedure”.

The researchers have developed the models in The Virtual Brain - the neuroinformatics platform for constructing and simulating brain network models in EBRAINS. They are built based on the individual EEG and structural MRI data of the patient. EBRAINS provides the necessary computing power for systematic parameter exploration of the high-resolution models, which are the key to success in this DBS study. 

“High resolution brain modeling with active tissue properties has been a focus in HBP and is unique to our approach” say two principal investigators of the study Andrea Protzner from the University of Calgary and Viktor Jirsa from INS. “For DBS and electroencephalography we do not necessarily need cellular resolution, but we have to be at least in the mm range to operate effectively, as the brain tissue varies extensively at this scale.”

To calibrate the models, the researchers measured each patient’s brain response to low-frequency stimulation and found out the models were able to replicate the measured response. “Therapeutic stimulation is applied continuously over time at high frequency to control the emotion regulation circuitry” explains Sora An from Ewha Womans University in Korea, the lead author in this study. “Our next step is to improve the tissue model by including more details on the biophysical mechanisms of therapeutic stimulation and then develop clinical applications for DBS based on the models.”

Text by Roberto Inchingolo

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This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (2020R1I1A1A01073605) and RP-Grant 2020 of Ewha Womans University to SA, Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grants (05299–2020) to ABP and (04126–2017) to ZHTK. Alberta Innovates Health Solutions provided the funding to ZHTK and RR for the clinical trial in which these patients were enrolled. This research was supported by the EBRAINS research infrastructure and funded through the European Union's Horizon 2020 Framework Programme for Research and Innovation under the Specific Grant Agreement No. 945539 (Human Brain Project SGA3) to VKJ.