Study on Human Neurons

We all know how essential it is for a human to have the ability to conjure specific moments from the vast array of experiences that have occurred in one’s life which forms a human memory. A group led by neuro engineers at Columbia Engineering have been able to find the first evidence about the individual neurons in the human brain. They say that these human neurons target specific memories during recall. As per their study, they found that there are recordings in neurosurgical patients who had electrodes implanted in their brains and have been examined how the patients' brain signals corresponded to their behaviour during they performing a virtual-reality object-location memory task. The researchers also found those 'memory-trace cells' which have their activity spatially tuned to the location where subjects remembered encountering specific objects. The study has been published in Nature Neuroscience. It has been evident from the studies that declarative memory is the the kind of memory one can consciously recall simply like our name, phone number, home address or one’s mother's name . This clearly relies on healthy medial temporal lobe structures in the brain that includes the hippocampus and entorhinal cortex (EC). However this team led by the neurologists has been able to measure the activity followed by single neurons by recording from the brains of 19 neurosurgical patients at several hospitals, including the Columbia University Irving Medical Centre. These patients had drug-resistant epilepsy which means they had already had recording electrodes implanted in their brains as a part of their clinical treatment. The researchers further took advantage of this opportunity and designed experiments as engaging and immersive VR computer games along with the bedridden patients who used laptops and hand held controllers to move through virtual environments. While in process of performing this task, they first navigated the subjects through the environment to learn the locations of four unique objects and then only the researchers removed the objects and confirmed with patients before moving through the environment and mark the location of one specific object on each trial. Then this team had measured the neurons activity that happened due to movement of the patients through the environment and marked their memory targets. Firstly, they identified purely spatially tuned neurons which were similar to place cells which always used to get activated when patients moved within the specific locations, irrespective of the subjects' memory target. "These neurons seemed only to care about the person's spatial location, like a pure GPS," said by Salman E. Qasim, Jacobs' PhD student and lead author of the study. Going forward, Jacobs and Qasim will head towards looking for evidence of how neurons represent memories in non-spatial contexts and can be better characterize their role in memory function. "We know now that neurons care about where our memories occur and now we want to see if these neurons care about other features of those memories, like when they occurred, what occurred, and so on," Qasim said.

By: Anuja Arora
Content: https://www.sciencedaily.com/releases/2019/11/191112095740.htm