DARPA claims breakthrough for the treatment of depression, anxiety and other mood disorders

DARPA's SUBNETS project aims to improve current understanding of various sub-networks of brain

Researchers working for the US Defense Advanced Research Projects Agency (DARPA) SUBNETS (Systems-Based Neurotechnology for Emerging Therapies) claim to have made a breakthroughs that could radically improve the treatment of depression, anxiety and other mood disorders.

DARPA's SUBNETS programme was started four years ago under the White House BRAIN Initiative. It aims to improve current understanding of various sub-networks of brain and discover the patterns exhibited by a healthy brain activity across these sub-networks.

Researchers working on the programme are currently trying to develop responsive, closed-loop therapies that can help treat neuro-psychiatric illnesses. To develop such therapies, researchers need to record and analyse brain activity with near-real-time neural stimulation.

The SUBNETS programme is being led by the researchers from the University of California, San Francisco (UCSF), who work in collaboration with the Massachusetts General Hospital and the University of Southern California (USC).

In the past three months, SUBNETS research team has reported - in three separate studies - breakthroughs that could pave the way for better treatment of depression and other neuropsychiatric illness in patients.

In the first study, published in the journal Nature Biotechnology, researchers from USC provided details of a new technology that can analyse and decode recorded neural signals to predict changes in mood in a person.

In the second study, published in journal Cell, the team reported identifying a specific sub-network of the brain that likely contributes to low mood, especially in individuals prone to anxiety. Researchers mapped those feelings to activity in the amygdala and hippocampus regions of the brain, which are usually linked to negative emotions and memory, respectively.

In the latest study, published in journal Current Biology, UCSF researchers revealed how they used open-loop neural stimulation to successfully relieve the symptoms of moderate to severe depression in some patients.

According to researchers, the unilateral neural stimulation delivered to the lateral orbitofrontal cortex (OFC) region in the brain modulated a sub-network which was found to contribute to depression. The stimulation produced acute, dose-dependent mood improvement in research participants suffering from moderate-to-severe baseline depression.

The study also revealed that the OFC stimulation corrected mood only in subjects who suffered from depression. In these subjects, the stimulation did not trigger mania symptom, such as grandiosity, hyperactivity or distractibility.

The research participants who did not suffer from depression remained unaffected by the OFC stimulation.

These results suggested that the lateral OFC stimulation was effective in normalising pathological activity in circuits that mediate mood variation.

"There are millions of veterans in the US who suffer from neuropsychiatric illness, and for many of them existing treatments do not offer meaningful relief," said Justin Sanchez, the director of DARPA's Biological Technologies Office, who oversees the SUBNETS programme.

"The results we have demonstrated just four years into SUBNETS have validated DARPA's approach and illuminated a path forward for developing a closed-loop system that addresses patients' unique needs."