Durham psychologists have discovered a new kind of GPS-like brain cells, furthering our understanding of spatial memory. The newly discovered vector trace cells store distance and direction data in memory, forming a map of our environment, and storing it away to use when necessary. These vector trace cells may also be implicated in the progression some types of dementia, like Alzheimer’s, as damage to them could cause memory loss regarding the locations of items. I sat down for a chat about their research with Dr. Steven Poulter and Dr. Colin Lever of the Department of Psychology.
Dr Poulter explained: “we’ve been interested in an understudied area of the brain, called the subiculum, which is part of the hippocampal formation network and may be the first to depreciate with the onset of Alzheimer’s. Looking at this area in rodents, we found cells that seem to code for where objects were.”
Dr Poulter explained how data was collected: “Using electrodes in the brains of rodents, we looked for voltage changes in single cells. Thus, we can identify what certain cells code for, using this to establish which part of the brain makes memory schemas the relative location of objects within an environment.”
Dr Lever went on to say that one of the first signs of Alzheimer’s onset is the inability to remember where objects are located. This may materialize in losing everyday items, forgetting where your glasses are, or where you set your cup of tea down.
Dr Lever added: “the subiculum does show normal ageing, as does every region in the hippocampus. The hippocampus reaches peak volume at 40, but then declines from there, getting smaller as you get older. However, in Alzheimer’s, cells seem to degenerate there at a faster rate, compared with normal ageing.”
Specifically, the normal ageing process is sped up in Alzheimer’s by the presence of beta-amyloid plaques. These are balls of built-up protein that disrupt normal cell function, so if they’re present in the newly discovered vector trace cells, retrieval of information regarding objects, locations and landmarks may be disrupted.
Despite this particular study focusing on the subiculum of rodents, Dr Poulter reassured me that this brain region is preserved across many species, from bats and rats, to humans, with similar physiological makeup, meaning it is highly likely vector trace cells will be found in our brains as well. This itself lends credence to the idea that damage to vector trace cells is responsible for faulty memory, and memory disorders, found in the elderly.
Whilst discussing the impacts their discovery could have on the medical and psychiatric fields, Dr Lever explained “specific spacial memory tests could be developed based on this finding, looking at remembering locations of objects through virtual reality, that may only take 20 minutes in a GP office, making it accessible and easy first step in dementia diagnosis for people across the UK, before more expensive brain imaging and memory testing. This might be available in doctors surgeries within ten years.”
“Diagnosis of Alzheimer’s is more about trying to find early makers, like the degradation of vector trace cells, so doctors than then focus on preventing further damage and degradation.” Adds Dr Poulter. “The current method of Alzheimer’s diagnosis is rather coarse, mainly revolving around autobiographical questions like what did you have for breakfast, so observing these cells might provide a way to diagnose Alzheimer’s in patients who are in the early stages of the disease, and still only displaying subtle symptomatology”.
Not only did this discovery cause ripples in healthcare and psychology, but also excited scientists interested in artificial intelligence. As Dr. Poulter says, their aim is to replicate the brain, so knowing a little bit more about its neuronal make-up, like the presence of vector trace cells are there, and how they work allows for them to more accurately formulate spatial information into memories and store these schemas.
Illustration: Anna Pycock