The research could lead to pills being developed to combat depression, anxiety, paranoia and obsessive-compulsive disorder.
American scientists implanted special light-sensitive proteins into the brains of rodents and used fibre-optic filaments to stimulate and monitor the animals’ responses.
The breakthrough process allows the researchers to control specific pathways in the rodents’ brains and measure the effect of differing levels of light.
The research could herald “a new chapter” in how we treat mental disorders, the scientists say. Researchers also believe their work could slow the ravages of dementia by stimulating brain activity.
The scientists’ groundbreaking techniques allowed them to map the brain’s neural circuitry and discover the genetic triggers that can cause certain categories of mental illness.
The project leader described it as a “major landscape shift that will bear huge fruits” in the battle to control psychiatric disorders.
He believes the drugs could be more powerful in reversing depressive conditions than the current best treatments.
Dr Karoly Nikolich, of Circuit Therapeutics, said: “It is very promising and we are heading for an entirely new chapter in how we can treat these conditions. It is only a matter of time before the drugs are developed.
“The tools we can use are becoming more sophisticated and we have so much data as we understand more about the genome [human DNA].
“Our goal is that people with depression, anxiety and OCD will be able to take a pill to modulate their behaviour and responses.” The pill could also replace certain anti-psychotic drugs and arrest the growing use of antidepressants.