title: Which way and how far? Tracking of translation and rotation information for human path integration.
abstract: Path integration, the constant updating of the navigator's knowledge of position and orientation during movement, requires both visuospatial knowledge and memory. This study aimed to develop a systems-level understanding of human path integration by examining the basic building blocks of path integration in humans. To achieve this goal, we used functional imaging to examine the neural mechanisms that support the tracking and memory of translational and rotational components of human path integration. Critically, and in contrast to previous studies, we examined movement in translation and rotation tasks with no defined end-point or goal. Navigators accumulated translational and rotational information during virtual self-motion. Activity in hippocampus, retrosplenial cortex (RSC), and parahippocampal cortex (PHC) increased during both translation and rotation encoding, suggesting that these regions track self-motion information during path integration. These results address current questions regarding distance coding in the human brain. By implementing a modified delayed match to sample paradigm, we also examined the encoding and maintenance of path integration signals in working memory. Hippocampus, PHC, and RSC were recruited during successful encoding and maintenance of path integration information, with RSC selective for tasks that required processing heading rotation changes. These data indicate distinct working memory mechanisms for translation and rotation, which are essential for updating neural representations of current location. The results provide evidence that hippocampus, PHC, and RSC flexibly track task-relevant translation and rotation signals for path integration and could form the hub of a more distributed network supporting spatial navigation. Hum Brain Mapp 37:3636-3655, 2016. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Department of Psychological and Brain Sciences and Center for Memory and Brain, Boston University, Boston, Massachusetts.|Massachusetts General Hospital, Athinoula A. Martinos Center for Biomedical Imaging.
authors.forename: Elizabeth R
authors.initials: ER
authors.lastname: Chrastil
authors.affiliation: Department of Psychological and Brain Sciences and Center for Memory and Brain, Boston University, Boston, Massachusetts.|Massachusetts General Hospital, Athinoula A. Martinos Center for Biomedical Imaging.
authors.forename: Katherine R
authors.initials: KR
authors.lastname: Sherrill
authors.affiliation: Department of Psychological and Brain Sciences and Center for Memory and Brain, Boston University, Boston, Massachusetts.
authors.forename: Michael E
authors.initials: ME
authors.lastname: Hasselmo
authors.affiliation: Department of Psychological and Brain Sciences and Center for Memory and Brain, Boston University, Boston, Massachusetts.|Massachusetts General Hospital, Athinoula A. Martinos Center for Biomedical Imaging.
authors.forename: Chantal E
authors.initials: CE
authors.lastname: Stern
mesh_terms: D001921:Brain / Q000000981:diagnostic imaging / Q000502:physiology*; D001931:Brain Mapping; D005260:Female; D006801:Humans; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology; D008959:Models, Neurological; D009039:Motion Perception / Q000502:physiology*; D009483:Neuropsychological Tests; D011930:Reaction Time; D012399:Rotation; D012649:Self Concept; D013028:Space Perception / Q000502:physiology*; D065854:Spatial Navigation / Q000502:physiology*; D013997:Time Factors; D014741:Video Recording; D000076142:Virtual Reality; D055815:Young Adult
keywords: functional magnetic resonance imaging; hippocampus; navigation; parahippocampus; retrosplenial cortex; working memory