Brain’s emotion code is cracked

PATTERNS of electrical brain activity have been used to tell when people are sad, happy or depressed. The advance could lead to new ways of treating those with depression or anxiety using devices that constantly monitor their mood via brain signals.

By activating electrodes implanted in specific regions of people’s brains – a process
called deep brain stimulation, or DBS – it is already possible to ease conditions including depression, bipolar disorder, Tourette’s syndrome and obsessive compulsive disorder. There have also been advances towards “mind-reading”: deducing memories and internal thoughts by monitoring the brain’s electrical activity. Ultimately, the aim is to program the devices so they activate mood-uplifting brain networks when they detect potentially dangerous negative emotions.

Now it is possible to decipher mood too. “We’ve discovered how mood variations can be decoded from neural signals in the human brain,” says Maryam Shanechi at the University of Southern California, who is lead researcher on the project. “It’s a significant step towards creating new therapies that use brain stimulation to treat debilitating mood and anxiety disorders.” Shanechi and her colleagues recruited seven people with epilepsy who had each been temporarily fitted with implanted electrodes to identify major sources of their seizures. By monitoring the electrical output from the electrodes, the team homed in on “fingerprint” patterns of activity across the brain that closely corresponded with the specific moods each person was experiencing.

Shanechi stresses that decoding is only a first step. For a device to be able to treat people as well as monitor mood, for example, the team needs to establish which parts of the brain must be stimulated to head off impending depression or anxiety. The safety and inconvenience of implanting electrodes is also a major hurdle, but non-invasive systems are being developed that use electrodes on the head to stimulate brain regions. “Mood is very hard to measure,” says Thomas Schlaepfer, who uses DBS to treat depression at University Hospital Freiburg in Germany. “The fact they find mood correlates with predictive electrical signals is stunning, and a lovely concept.” ■

Source : www.newscientist.com