Kate J. Jeffery, Distorting the metric fabric of the cognitive map, Trends in Cognitive Sciences, Volume 19, Issue 6, June 2015, Pages 300-301, ISSN 1364-6613, DOI: 10.1016/j.tics.2015.04.001..
Grid cells are neurons whose regularly spaced firing fields form apparently symmetric arrays, or grids, that are thought to collectively provide an environment-independent metric framework for the brain’s cognitive map of space. However, two recent studies show that grids are naturally distorted, revealing greater local environment-specific effects than previously recognized.