Just like a very complicated computer, our brains control our thoughts and behaviours via electrical bursts of activity. Essentially, that means we should be able to both understand and control how it works, but our brains are coded in a language we don't understand just yet.

Now, however, researchers from University College London in the UK have developed a new method that has allowed them to both read and write brain signals in mice using flashes of light.

The development takes us a step closer to better understanding how the brain works, and potentially how to program it.

Their method involved genetically encoding activity sensors that allow nerve cells to visibly light up when they're active. The neuroscientists also genetically engineered these same nerve cells to express light-sensitive proteins, which means that they could be activated with flashes of light. 

The technique has now been described in Nature Methods, and they're hoping it will allow us to finally learn more about the "language" our brain uses to process information.

"Combining reading and writing of activity in the same neurons in the intact brain could revolutionise how neuroscientists can interact with and understand brain activity," Michael Hausser, the lead author of the study, said in a press release.   

"One of the best things about having an extended conversation with someone is that you can really get to know them. With time, their responses can give you a feel for the key questions to ask in order to understand their character," added Hausser. 

"Just as we combine specific words into sentences that elicit a reply from someone we talk to, we used light to activate specific combinations of nerve cells in the intact brain and record how the other cells respond. In this way, we hope to be able to ask the brain questions and, from its answers, better understand how it works."

To do this, the team used a holographic technique to split a beam of light and direct it into individual cells - this allowed them to activate multiple brain cells at once.

They used this technique to activate a group of neurons in the cortex that are specifically responsive to the sensation of touch - essentially try tricked the mice's brains into "feeling" touch.

The team then recorded the flashes of activity in both the activated neurons and those neighbouring it, which allowed them to essentially "interrogate" the circuit to measure the resulting pattern of brain activity.

As the release explains

These experiments could be repeated in the same sets of neurons in the same animals over days and even weeks, allowing an extended 'conversation' with the circuit. In future, the team hope that by replacing a physical stimulus with precise, holographically controlled brain activity, the 'neural code' of sensory perception can be cracked.

 "We are very excited to use this technology to probe the basis of how groups of neurons and ultimately the brain stores and processes information from the world around us," said one of the lead researchers Adam Packer in the release

"This work provides a new way for neuroscientists to have a long-term and engaging conversation with the cerebral cortex in the brain of a mouse. Crucially, since the methods of both recording and activation rely on light, this technique is flexible and non-invasive."

Source: PsyPost