‘Grid cells in our mind map the whole world — focus your attention to use the brain best’

May-Britt Moser is a Nobel Laureate in Physiology. The Norwegian neuroscientist spoke to Srijana Mitra Das at Times Evoke Evolve about how our brain understands places, memories, fragrances — and our core passion:

- Srijana Mitra Das

Please tell us about your discovery of how our mind understands locations?

Some years ago, Edvard Moser and I began studying cells in the brain’s hippocampus. We worked with John O’Keefe in London on this — later, we all shared the Nobel Prize. John was interested in what he called ‘place cells’ — these are active at one specific place in the environment of our brain — because he knew of historical procedures where, for patients suffering from epileptic seizures, parts of the brain, including the hippocampus on both sides, had to be removed. When this was done, the patients were intellectually and socially fine — but they could not find their way around or remember new episodes, faces or names. John found hippocampal cells help encode locations in the environment — losing them means losing that information. When Edvard and I returned to

Norway, we asked, where is this spatial information coming from? We began researching the entorhinal cortex, a structure in the brain that talks to the hippocampus. With sensors, we recorded tiny electrical signals from individual cells. We found single cells in this formation had many activity fields in the environment, distributed in a way that resembled hexa- gonal tiling on a floor — we called this structure ‘grid cells’ whose field covers the entire environment. We also found it is possible for the work of different-sized grid cells to result in one activity field, like the place cells in the hippocampus — this supports the idea that entorhinal grid cells provide the hippocampus with spatial information and self-motion generated metrics, integrating speed and direction.