New research shows that weakening the connections between specific groups of brain cells can prevent the recall of fear memories in mice. The study, published earlier this week in the journal Neuron, has led some – including the study authors themselves – to speculate that this will eventually lead to treatments for conditions such as post-traumatic stress disorder and, inevitably, to news stories mentioning the 2004 film Eternal Sunshine of the Spotless Mind, in which an estranged couple undergo a procedure to erase memories of each other from their brains.

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Woong Bin Kim and Jun-Hyeong Cho of the University of California, Riverside used a combination of sophisticated techniques to identify those brain cells in mice that encode a specific type of fearful memory, and then to suppress them, so that the memory could not subsequently be “reactivated”.

Contrary to some of the news stories, however, this is not “a new approach to wiping memories from the brain”. Over the past five years, there has been a whole series of studies using optogenetics to manipulate memories in various ways, most notably from Susumu Tonegawa’s lab at the Massachusetts Institute of Technology. The novelty of this new study is the identification of the neuronal circuitry that encodes this particular type of fear memory – it has determined exactly which cells in the mouse brain do so and, equally importantly, the precise pattern of the connections they form with neurons in other parts of the brain.

So does this bring us one step closer to making Charlie Kaufman’s film a reality, as some have claimed? In 2013, at least one commentator suggested that optogenetics is hugely overhyped, and that it is nothing more than an experimental tool which has no therapeutic value.

But this is not the case: last year, a blind woman from Texas became the first person in the world to receive optogenetic therapy, and has been recruited with others for a clinical trial to test its efficacy in treating retinitis pigmentosa, which causes progressive degeneration of the light-sensitive cells at the back of the eye.

This trial involves injecting a virus carrying the Channelrhodopsin gene into patients’ eyes, in the hope that it will be taken up by cells in the retina, so that natural light entering the eyes will stimulate them to send signals along the optic nerve to the brain.

The effectiveness of such a treatment remains to be seen, and optogenetic treatments for manipulating memories in the human brain face far bigger challenges.

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For example, the method of using viruses has its limitations, and many of the studies done in mice involve techniques which will never be feasible in humans. And although the brains of mice and men are similar in many ways, there are also major anatomical differences between them, and the approach that Kim and Cho used to identify the amygdala cells is not applicable to humans. Finally, the amygdala lies deep in the brain, so the cells could not be activated by natural light, and would instead require an optical fibre placed into the brain, which would make any such therapy more invasive.

It is possible that these challenges could eventually be overcome in the distant future, so that we can have optogenetic erasure of memories from the human brain. Meanwhile, research like this should continue to advance our understanding of how the brain works, by revealing more of the finer details about how its cells function together to encode, store and retrieve different kinds of memories.

• Mo Costandi trained as a developmental neurobiologist and now works as a freelance science writer