Using rats, the experiments were successful. According to a January 2014 article published by the US National Library of Medicine National Institutes of Health, optogenetic technology possibly holds the answer for helping patients suffering from depression (1).
Paul R. Albert, PhD writes that optogenetic technology, “gives a whole new meaning to light therapy’.” Albert states this type of therapy “is potentially more effective and rapid and has fewer adverse effects than classic light therapy or pharmacological approaches to treat mental illness.”
Several recent studies for using “optogenetic stimulation” to fight depression demonstrated this potential in modifying not only depression, but also “anxiety-related behaviors in animal models.”
Clinical depression is a very “common psychopathological disorder” that should not be confused with temporary depression or sadness (2). Clinical depression seizes the patient who experiences “persistent negative moods, feelings of sadness, loss of interest and motivation.”
According to Science Alert, in these latest studies scientists first targeted certain brain cells and “genetically” sensitized them to light. Next, they activated these cells with the use of light pulses (3).
The area of the brain researchers targeted was the “hippocampus” known as the “dentate gyrus”. This is the area of the brain where “new episodic memories” are created (4). Other responses that take place in this region, include “responses of avoidance and of appetite.” The dentate gyrus also keeps a record of both “positive and negative experiences.”
The goal is to stimulate this region of the brain to create “happy memories” to aid in combating depression.
The first thing that the scientists did was to genetically engineer a harmless virus. The virus is designed to target specific DNA cells within the brain. With the target identified, the virus then infects the designated cells or more aptly, certain proteins within the cells.
The virus then transforms the proteins into being light sensitive to specific light wavelengths. The rats were also implanted with light fibers. Next, the light pulse is transmitted through the light fibers and the animal responds, or more aptly the infected protein in the cells responds.
Scientists were able to achieve the desired effect in the rats – an artificial happy memory. All of this was made possible by the interaction between the virus protein and the light fiber. The protein channels that are sensitized to light then respond.
Japanese Nobel Prize Winner Cures Mouse’s Depression
Rocket News reported in June 2015 that “Japanese scientists treat depressed male mice by making them remember happy times with lady-mice” (5).
The team of scientists that reversed the depression is led by 1987 Nobel Prize winner for Physiology or Medicine, Susumu Tonegawa. The scientists recorded the firing of the male’s neurons while being with the female mouse.
To test the theory, the male mouse was then isolated and placed in a stressful situation for 10 days. The mouse was wrapped in plastic for 40 minutes each day. As a result, the mouse demonstrated signs of depression, such as lack of interest in sugar water.
Next, the scientists implanted fiber optics in the mouse. The neurons active during the mouse’s earlier encounter with the female mouse were targeted with blue pulses of light from the fiber optics.
The team concluded, “We are seeing a connection between artificially stimulating happy memories and a relief of the symptoms of depression.”
While there will need to be more research, so far all of the data is very promising for this type of light therapy. In fact, it could lead to other possible treatments for other types of mental illness as well as various substance addictions.
References & Image Credits:
(2) TSW: New Cochlear Gene Therapy May Pave the Way for Future Depression Therapy
(3) Science Alert
(4) Wikipedia: Dentate Gyrus
(5) Rocket News