|Posted on December 29, 2014 at 1:20 PM|
Written by Matthew Peniket
Mind control once was thought to be purely fictitious, but recent developments have made this concept a more plausible possibility. Optogenetics is the controlling of certain pathways in the brain by shining light onto a particular neuron. Under normal circumstances, this would achieve nothing, but with genetic modification, this will trigger the neuron to fire.
But how does this work? Chlamydomonas reinhardtii is a green alga that is reliant upon two flagella to move. The action of these two flagella is determined by an ion channel (a protein which allows ions to pass through it). The distinctive feature of this ion channel is that it is activated by light - i.e. when light is incident upon it, it ‘opens up’ and allows ions to pass through. This protein is called channelrhodopsin.
The gene that codes for this channelrhodopsin protein can be cut out of the DNA of the C. reinhardtii and subsequently transferred into the DNA of a mouse. This is done by inserting the channelrhodopsin gene into a modified virus, followed by the injection of this virus into the brain. After this, a fibre-optic cable is inserted into the brain of the mouse so that when light of a certain wavelength is shone upon a certain type of neuron, the light-gated ion channel will open and the neuron will be caused to fire. This will allow the mapping out of certain pathways in the brain dependent on this type of neuron firing. This method also means that if certain neurons are programmed to fire under the presence of light in mice, certain actions will be performed, such as walking in circles. Halorhodopsin is another ion channel which can be inserted into the brain, however when this ion channel is exposed to light, the activity of that neuron will be silenced. Some of these remarkable mind control-esque phenomena resulting from optogenetic techniques can be viewed here: http://www.youtube.com/watch?feature=player_embedded&v=I64X7vHSHOE.
There are a variety of potential implications of optogenetics. Our knowledge of the exact workings of the brain is currently limited. Optogenetics will offer a highly precise means of mapping out the structure of the brain and through a better understanding of the structure of the brain, we will be able to develop new treatments for diseases which affect the brain. One example of an interesting recent experiment involved the melanin concentrating hormone (MCH) located in the hypothalamus, which is thought to be involved in the regulation of sleep. In a recent study (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3685832/), when MCH neurons were activated by optogenetic means, sleep was induced in mice. This could potentially be applied therapeutically in the treatment of insomnia. It is thought that optogenetics could also be used to treat diseases such as Parkinson’s.
Co-discoverer of the structure of DNA (Francis Crick) suggested in 1979 that a major challenge facing neuroscience was the need to have a means of influencing the action of a single type of cell in the brain. With optogenetics, this is now possible.
Original image, copyright Emma Lewis.