INVESTIGATING SPATIAL MEMORY AND NAVIGATION IN DEVELOPMENTAL AMNESIA: EVIDENCE FROM A GOOGLE STREET VIEW PARADIGM, MENTAL NAVIGATION TASKS, AND ROUTE DESCRIPTIONS KATHERINE A. HERDMAN A DISSERTATION SUBMITTED TO THE FACULTY OF GRADUATE STUDIES IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY GRADUATE PROGRAM IN PSYCHOLOGY YORK UNIVERSITY TORONTO, ONTARIO August 2018 © KatherIne A. Herdman, 2018 Abstract This dissertation examined the integrity of spatial representations of extensively travelled environments in developmental amnesia, thereby elucidating the role of the hippocampus in forming and retrieving spatial memories that enable flexible navigation. Previous research using mental navigation tasks found that developmental amnesic case H.C., an individual with atypical hippocampal development, could accurately estimate distance and direction between landmarks, but her representation of her environment was fragmented, inflexible, and lacked detail (Rosenbaum, Cassidy, & Herdman, 2015). Study 1 of this dissertation examined H.C.’s spatial memory of her home environment using an ecologically valid virtual reality paradigm based on Google Street View. H.C. and control participants virtually navigated routes of varying familiarity within their home environment. To examine whether flexible navigation requires the hippocampus, participants also navigated familiar routes that had been mirror-reversed. H.C. performed similarly to control participants on all route conditions, suggesting that spatial learning of frequently travelled environments can occur despite compromised hippocampal system function. H.C.’s unexpected ability to successfully navigate mirror-reversed routes might reflect the accumulation of spatial knowledge of her environment over the 6 years since she was first tested with mental navigation tasks. As such, Study 2 investigated how spatial representations of extensively travelled environments change over time in developmental amnesia by re-testing H.C. on mental navigation tasks 8 years later. H.C. continued to draw sketch maps that lacked cohesiveness and detail and had difficulty sequencing landmarks and generating detours on a blocked route task, suggesting that her overall representation of the environment did not improve over 8 years. Study 3 thoroughly examined the integrity of H.C.’s detailed representation of the environment using a route ii description task. H.C. accurately described perceptual features of landmarks along a known route, but provided inaccurate information regarding the spatial relations of landmarks, resulting in a fragmented mental representation of the route. Taken together, these results contribute meaningfully to our current understanding of the integrity of spatial representations of extensively travelled environments in developmental amnesia. Non-spatial factors that could influence performance on navigation and spatial memory tasks are discussed, as is the impact of these results on theories of hippocampal function. iii Acknowledgements I would like to first thank my supervisor, Dr. Shayna Rosenbaum, for her support over the past six years. It has been an honour to learn from such an accomplished researcher and I look forward to continued collaboration in the years to come. I also thank my dissertation advising committee, Drs. Doug Crawford and Norman Park, for their helpful feedback. I would also like to thank Yasha Amani and Anna Waisman for their assistance with testing and scoring, and Dr. Malcolm Binns for sharing his statistical expertise. I am grateful to the members of the Rosenbaum Memory Lab, both past and present, and the kind, brilliant women in my cohort, all of whom formed an exceptional support system throughout graduate school. I am especially grateful to H.C. and her family for their enthusiastic participation in these studies and their ongoing commitment to research. Finally, I would like to thank all of my friends and family for their endless patience and encouragement, especially my parents, Jan and Phil, and sister, Julia, whose unwavering support made this achievement possible. This work was supported by a 3-year Canadian Institutes of Health Research (CIHR) Doctoral Research Award and 1-year Ontario Graduate Scholarship granted to K.A.H., in addition to Natural Sciences and Engineering Research Council of Canada (NSERC) and CIHR grants awarded to R.S.R. iv Table of Contents Abstract ................................................................................................................................... II Table of Contents ..................................................................................................................... v List of Tables .......................................................................................................................... viI LIst of Figures ........................................................................................................................ viII LIst of AppendIces .................................................................................................................... x CHAPTER 1 .............................................................................................................................. 1 General IntroductIon ............................................................................................................... 1 MnemonIc FunctIon of the HIppocampus ......................................................................................... 2 Evidence that the HIppocampus Is SpecIalIzed for AllocentrIc SpatIal Memory ................................. 3 Preserved SchematIc RepresentatIons of Remote EnvIronments In Adult-Onset AmnesIa ................ 6 Impaired Detailed Representations of Remote Environments in Adult-Onset AmnesIa ..................... 7 SpatIal Memory Development In Developmental AmnesIa ............................................................... 8 Role of the HIppocampus In Flexible Navigation .............................................................................. 13 Tools Used to InvestIgate SpatIal Memory ....................................................................................... 15 OvervIew of StudIes ........................................................................................................................ 16 CHAPTER 2 ............................................................................................................................. 21 Study 1: Intact VIrtual RealIty NavIgatIon In Developmental AmnesIa .................................... 21 Methods ......................................................................................................................................... 26 Participants ......................................................................................................................................... 26 Stimuli & Apparatus ........................................................................................................................... 31 Procedure ........................................................................................................................................... 32 Analysis ............................................................................................................................................... 36 Results ............................................................................................................................................ 39 Destination Reached .......................................................................................................................... 40 Number of Pauses .............................................................................................................................. 40 Directness of Travel ............................................................................................................................ 42 Speed of Navigation ........................................................................................................................... 44 Progression Errors .............................................................................................................................. 46 Navigation Strategies Questionnaire .................................................................................................. 48 DiscussIon ....................................................................................................................................... 48 How Might Spatial Representations of Environments Form Without a Typically Functioning Hippocampus and the Full Support of Episodic Memory? ................................................................. 51 Flexible Navigation: Reconciling Discrepancies Between Mental Navigation Tasks and Virtual Reality ............................................................................................................................................................ 54 Limitations .......................................................................................................................................... 60 Summary ............................................................................................................................................ 63 CHAPTER 3 ............................................................................................................................. 64 Study 2: Do representations of frequently travelled environments improve with time and experience in