( CNN ) -- The hottest field in science this past decade has been neuroscience . That explosion in research , and our understanding of the human brain , was largely fueled by a new technology called functional magnetic resonance imaging ( fMRI ) that became widely available in the 1990s . Well look out ! Another technology-based neuroscience revolution is in the making , this one perhaps even bigger . The term to watch for in 2013 is `` optogenetics . '' It 's not a sexy term , but it is a very sexy technology . The heritage of optogenetics goes way back to 1979 , when Nobel Laureate Francis Crick , co-discoverer of the structure of DNA with James Watson and Rosalind Franklin , suggested that neuroscientists should seek to learn how to take control of specific cells in the brain . Well , that certainly would seem to be an advance with great potential . Imagine being able to turn the neurons in an animal 's brain on and off from the outside . Sounds like you 'd be turning the creature into a robot , sounds like science fiction . Right ? Well , flash forward thirty-some years , and guess what , optogenetics is a reality ! Here 's how it works ... roughly . An obvious approach would be to stick a tiny electrode into an animal 's brain and stimulate the cells using electricity . Today we have tiny microelectrodes , but they are still too crude for the job . Crick speculated that light could be the tool to use . That turned out to be true : Optogenetics involves inserting fiber-optics tools into an animal 's brain , in order to control the target neurons using pulses of light as a trigger . Learning to shine light on a neuron is not the whole answer , though . In order for the method to work , the neurons have to be re-engineered so that they react to the light . That was made possible by the amazing discovery of a kind of protein that can be used to turn neurons on and off in response to light . The exotic light-sensitive protein is not present in normal neurons , so scientists designed a way to insert it . That is accomplished through a type of gene engineering called `` transfection '' that employs `` vectors '' such as viruses to infect the target neuron , and , once there , to insert genetic material that will cause the neuron to manufacture the light-sensitive protein . Put it all together , and you have that sci-fi-sounding technology : genetically-engineered neurons that you can turn on and off at will , inside the brain of a living and freely-moving animal . It is the combined use of optics and genetics that give optogenetics its name , but it 's not the `` how '' that makes optogenetics exciting , it is the `` what . '' Scientists did n't really develop it to `` take over '' a creature 's brain . They developed it , like fMRI , to learn about the brain , and how the brain works , in this case by studying the effect of stimulating specific types of neurons . The technology is already beginning to pay off , and despite its recent invention , the word on the street is that a Nobel Prize is n't far off . In one application of optogenetics , scientists investigated how neurons that make dopamine , a neurotransmitter in the brain , may give rise to feelings of reward and pleasure . That work may help scientists understand the pleasure-related pathologies involved in clinical depression . In another application , scientists selectively stimulated brain cells in animal models of Parkinson 's disease , a disease that involves the disruption of information-processing in the brain . That research gave new insight into the circuitry involved in the disease , and the way that the therapies we currently prescribe for it operate . It has also suggested new directions for therapeutic intervention . Schizophrenia is another disorder that involves information processing issues in the brain . The illusion of hearing voices , for example , may arise from the failure of an internal mechanism for notifying a person when his or her thoughts are `` self-generated . '' Optogenetics has been employed to better understand a kind of brain activity called `` gamma oscillations '' that appear abnormal in schizophrenia -- and also in autism . Today , we are a long way from the era when a single person working with an assistant or two can make a revolutionary technological breakthrough . It took , instead , decades of work in many fields , which came together , only very recently , to bring Crick 's vision to fruition . But now that it 's here , optogenetics is destined to change the way we treat mental illness , and eventually , even , the way we understand ourselves as human beings . The opinions expressed in this commentary are solely those of Leonard Mlodinow .
Leonard Mlodinow The first thing I noticed about the new iPhone 7 is that it feels a lot lighter than its predecessor. Mlodinow : Imagine being able to turn neurons in a brain on and off from the outside . He says optogenetics can be used to gain insights on diseases , mental illnesses . Mlodinow : It will change the way we understand ourselves as human beings .