Due to new kinds of light-sensitive protein inside monkey brains, scientists found that blue light triggered off deep-rooted nerve cells inside their heads. On the other hand, orange light stopped that extra activity. When light pulses were beamed from outside a monkey's head, it was found to activate nerve cells much inside its brain. The experiment was considered to be a sort of external control that was outlined on October 20 at the annual meeting of the Society for Neuroscience. Someday, it might support scientific efforts to treat cognitive disorder such as epilepsy.
If nerve cell behaviour can be controlled with light, which is a well-known method named optogenetics, it would need thin optical fibres that should be implanted inside the brain. This biological technique uses light to control cells within living tissues, mostly neurons, which have been genetically modified to express light-sensitive ion channels. This is an important neuromodulation method that leverages various techniques right from optics and genetics in order to manage the activities of neurons within living tissues inside mobile animals.
These manipulation effects can be monitored in real-time, with the central reagents being light-sensitive proteins. However, these might lead to infections, inflammation and tissue damage, according to study coauthor Diego Mendoza-Halliday of MIT. Being an expert in optogenetics, Diego Mendoza-Halliday explains his work: "My research uses high-end electrophysiological and optogenetic techniques in non-human primates to examine the brain's mechanisms underlying visual attention, working memory, and their interaction, at the level of individual neurons, neuronal ensembles, and across multiple brain areas."
His team made a novel light-responsive molecule, called SOUL. It was used to identify extra dim light. The SOUL was injected into macaque monkeys' brains. Following that, the researchers beamed some blue light through a hole in the skull. This activated SOUL-containing neurons, embedded almost 5.8 millimetres in the brain. On the other hand, one dose of orange light put a stop to it. While SOUL is not able to sense light that is beaming through the macaques' skulls, the system works through the skull in mice, according to the scientists.
If LEDs are embedded within human skulls, they might someday be able to administer brain diseases. This kind of system could temporarily abort nerve cells gearing up to erupt into an epileptic seizure. "This is basically scooping out a piece of brain and then putting it back in a few seconds later," when the risk of undergoing a seizure has reduced significantly, said Mendoza-Halliday.