Optogenetics is the amazing field that combines optics and genetics in order to control events in living cells. First predicted by Francis Crick (yes, THAT Crick) in 1999, a breakthrough came in 2005 when researchers found that mammalian neurons could be targeted and manipulated through this process (Fancy!). Optogenetics depends on manipulating channelrhodopsin, a type of chemical pathway in cells that has the unique ability of being controllable with light. It allows for them to be activated or suppressed when differently colored lights are directed at points on the membrane, changing their chemical balance. One of the most significant results of this is that scientists can selectively fire individual or groups of neurons in the brain with a high degree of accuracy. Sparking a mini-revolution in neurosciences, optogenetics allows the study of specific brain functions, including behavior. Since exploding in 2006, researchers have discovered methods to control the ability for mice to awake from a nap, the speed of eye movements in nonhuman primates, changing of social behaviors (such as angry to friendly) and possibly to teach new cells in the eye to see. The latter is one of the first movements towards therapeutic uses, aiming to improve or return sight to those whose primary sight cells (cones and rods) are dead. Tests on rodents seem to indicate that optogenetics will allow for possible therapies for human brain disorders, but it is unknown if some practices will scale to the complexity of the human brain.

Guest article written by Andrew Kays (ThePublicScience.tumblr.com)

Light Work

Understanding more about the human brain’s estimated 100 billion interconnected nerve cells, or neurons, could help us develop new treatments for disorders such as Parkinson’s disease, autism, schizophrenia and epilepsy. One method of investigating brain activity is to genetically engineer an animal, such as a mouse, so that its neurons produce a light-sensitive protein, opsin. Neuron activity can then be triggered by shining light on the brain, once it’s exposed in the anaesthetised animal. The computer simulation here illustrates a light beam hitting clusters of opsin on a neuron surface. The resulting nerve signals can be detected in connected neurons by inserting tiny probes to measure the electrical and genetic activity inside them. Scientists have recently developed a computer-guided robotic arm to insert the probes with greater accuracy than previously possible.

Written by Mick Warwicker

  • Ed Boyden
  • MIT McGovern Institute and Sputnik Animation
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TED Talk: Gero Miesenboeck reengineers a brain

I used to want to be a neurologist so badly. This is why. 

“Somewhere in pattern like this, there is you. Your perceptions, your emotions, your memories, your plans for the future. But we don’t know where, since we don’t know how to read the patter. We don’t understand the code used by the brain. To make progress, we need to break the code. But how?”