title: Context-dependent spatially periodic activity in the human entorhinal cortex.
abstract: The spatially periodic activity of grid cells in the entorhinal cortex (EC) of the rodent, primate, and human provides a coordinate system that, together with the hippocampus, informs an individual of its location relative to the environment and encodes the memory of that location. Among the most defining features of grid-cell activity are the 60° rotational symmetry of grids and preservation of grid scale across environments. Grid cells, however, do display a limited degree of adaptation to environments. It remains unclear if this level of environment invariance generalizes to human grid-cell analogs, where the relative contribution of visual input to the multimodal sensory input of the EC is significantly larger than in rodents. Patients diagnosed with nontractable epilepsy who were implanted with entorhinal cortical electrodes performing virtual navigation tasks to memorized locations enabled us to investigate associations between grid-like patterns and environment. Here, we report that the activity of human entorhinal cortical neurons exhibits adaptive scaling in grid period, grid orientation, and rotational symmetry in close association with changes in environment size, shape, and visual cues, suggesting scale invariance of the frequency, rather than the wavelength, of spatially periodic activity. Our results demonstrate that neurons in the human EC represent space with an enhanced flexibility relative to neurons in rodents because they are endowed with adaptive scalability and context dependency.
authors.affiliation: Sarah Cannon, St. David's Medical Center, Austin, TX 78705; zoltan@utexas.edu.|Department of Psychology, The University of Texas at Austin, Austin, TX 78712.|Department of Cognitive Psychology, Eötvös Loránd University, 1064 Budapest, Hungary.
authors.forename: Zoltan
authors.identifier: 0000-0002-6515-9683
authors.initials: Z
authors.lastname: Nadasdy
authors.affiliation: School of Medicine, Baylor College of Medicine, Houston, TX 77030.
authors.forename: T Peter
authors.initials: TP
authors.lastname: Nguyen
authors.affiliation: Department of Cognitive Psychology, Eötvös Loránd University, 1064 Budapest, Hungary.|Systems and Control Laboratory, Institute for Computer Science and Control, Hungarian Academy of Sciences, 1111 Budapest, Hungary.|Brain Imaging Centre, Research Centre for Natural Sciences, Hungarian Academy of Sciences, 1117 Budapest.
authors.forename: Ágoston
authors.initials: Á
authors.lastname: Török
authors.affiliation: Seton Brain & Spine Institute, Austin, TX 78701.|Department of Neurology, Dell Medical School, The University of Texas at Austin, Austin, TX 78712.
authors.forename: Jason Y
authors.initials: JY
authors.lastname: Shen
authors.affiliation: Seton Brain & Spine Institute, Austin, TX 78701.|Department of Neurology, Dell Medical School, The University of Texas at Austin, Austin, TX 78712.
authors.forename: Deborah E
authors.initials: DE
authors.lastname: Briggs
authors.affiliation: Seton Brain & Spine Institute, Austin, TX 78701.|Department of Neurology, Dell Medical School, The University of Texas at Austin, Austin, TX 78712.
authors.forename: Pradeep N
authors.initials: PN
authors.lastname: Modur
authors.affiliation: Department of Psychology, The University of Texas at Austin, Austin, TX 78712.|Seton Brain & Spine Institute, Austin, TX 78701.|Department of Surgery, Dell Medical School, The University of Texas at Austin, Austin, TX 78712.|Department of Psychiatry, Dell Medical School, The University of Texas at Austin, Austin, TX 78712.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Buchanan
mesh_terms: D000328:Adult; D018728:Entorhinal Cortex / Q000473:pathology / Q000503:physiopathology*; D004827:Epilepsy / Q000473:pathology / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D009474:Neurons
keywords: entorhinal cortex; grid cell; human; single unit; spatial memory