Stanford University researchers claim that they have identified a specific group of cells that can be direct targets of deep brain stimulation (DBS), a Parkinson's treatment.
Lead researcher Karl Deisseroth attributes this advance to a technique to systematically characterize disease circuits in the brain.
The researcher says that the NSF-funded technology, termed optogenetics, enabled them to precisely control individual components of the circuit implicated in Parkinson's disease.
The novel technology uses light-activated proteins, originally isolated from bacteria, in combination with genetic approaches to control specific parts of the brain.
It is a vast improvement over previous methods because it allows researchers to precisely stimulate neurons, and measure the effect of treatment simultaneously in animals with Parkinson's-like symptoms.
Deisseroth's team found that they could reduce disease symptoms by preferentially activating neurons that link to the subthalamic nucleus region of the brain.
The researchers first treated these specific cells in a way that made them sensitive to stimulation by blue light, and then implanted an optical fibre in the brain.
When researchers rapidly flashed blue light inside the animals' brains the disease symptoms improved.
They said that treating with slower flashes of light actually made the symptoms worse, and targeting other kinds of cells had no effect at all, indicating both proper cell type and stimulation frequency are crucial components of effective treatment.
According to the research team, flashing blue light on portions of the same neurons found closer to the outer surface of the brain had an effect similar to treatment deep within the brain, raising the possibility that researchers may be able to develop treatments that are less invasive than current options.
Deisseroth said: "The brain is an electrical device, but it is a very complicated device. Think of it as an orchestra without sections: all of the types of instruments, or cells, are mixed together. Treatments like DBS are unrefined, in that they stimulate all of the cells or instruments. The optogenetic approach allows us to control stimulation of specific cells in the brain on the appropriate timescale, much like a conductor directing specific sections of an orchestra at the appropriate time."
He added: "We need to understand the players before we can develop effective treatment strategies."
An article on the research team's work has been published in the journal Science.