LANDMARK PROCESSING BY HEAD DIRECTION CELLS Yave Roberto Lozano Navarro Thesis submitted to University College London for the degree of Doctor of Philosophy in Neuroscience September 2015 1 Contents DECLARATION ___________________________________________ 7 ACKNOWLEDGEMENTS ___________________________________ 8 ABBREVIATIONS _________________________________________ 9 ABSTRACT _____________________________________________ 11 I DESCRIPTION OF THE RESEARCH PROJECT ______________ 12 II REVIEW _____________________________________________ 17 Chapter 1 Behavioural and neural mechanisms of spatial navigation ___________________________________________ 17 1.1 Introduction ___________________________________ 17 1.2 Rodent navigation and memory ____________________ 18 1.2.1 Navigation strategies __________________________ 18 1.2.2 Sources of information for navigation ______________ 23 1.2.3 Reference frames _____________________________ 25 1.2.4 Role of landmarks in navigation __________________ 26 1.3 Spatially Modulated Cells ________________________ 30 1.3.1 Place cells __________________________________ 31 1.3.2 Head direction cells ___________________________ 33 1.3.3 Grid Cells ___________________________________ 35 1.3.4 Boundary vector cells __________________________ 37 1.4 Functional significance of spatially modulated cells _____ 38 Chapter 2 Neuroanatomy and functional properties of head direction cell circuits ___________________________________ 42 2.1 Introduction ______________________________________ 42 2.2 Neuroanatomy of the spatial navigation circuit ________ 43 2.3 Neuroanatomy of the head direction cell circuit ________ 45 2.4 Neuroanatomy of the landmark processing circuit ______ 50 2.5 Rodent visual system ___________________________ 55 2 2.6 Connectivity of the retrosplenial and postsubicular cortex 58 Chapter 3 Multisensory processing by head direction cells _____ 63 3.1 Introduction ___________________________________ 63 3.2 Properties of the head direction signal ______________ 64 3.3 Integration of sensory cues by head direction cells _____ 66 3.3.1 Influence of allothetic cues ______________________ 67 3.3.2 Influence of idiothetic cues ______________________ 71 3.4 Factors that influence landmark control ______________ 75 3.4.1 Learning of visual landmark cues _________________ 75 3.4.2 Learning of foreground and background cues _______ 77 3.4.3 Processing of geometric cues____________________ 79 3.5 Theoretical models of head direction cell activity_______ 80 3.6 Role of the RSC and the PoS in landmark processing __ 82 III EXPERIMENTAL CONTRIBUTIONS _______________________ 86 Chapter 4 General methods _____________________________ 86 4.1 Subjects ______________________________________ 86 4.2 Electrodes and microdrives _______________________ 86 4.3 Surgery ______________________________________ 87 4.3 Signal processing and tracking ____________________ 89 4.5 Screening procedure ____________________________ 90 4.6 Recording procedure ____________________________ 91 4.6.1 Recording arenas _____________________________ 91 4.6.2 Cue cards ___________________________________ 92 4.6.3 Cue control protocol ___________________________ 93 4.7 Data analysis __________________________________ 94 4.7.1 Spike sorting _________________________________ 95 4.7.2 Head direction cell rate map _____________________ 96 4.7.3 Head direction turning curve parameters ___________ 98 4.7.4 Head direction cell inclusion criteria _______________ 98 4.7.5 Head direction cell shift analysis __________________ 99 3 4.7.5.1 Head direction rate maps per session ____________ 99 4.7.5.2 Quantification of changes in the PFD ___________ 101 4.7.5.3 Kernel density estimates and population analysis __ 102 4.8 Histology ____________________________________ 102 Chapter 5 Population analysis of head direction cells ________ 103 5.1 Background and rationale _______________________ 103 5.2 Methods _____________________________________ 104 5.3 Head direction cell tuning curve parameters _________ 104 5.3.1 Estimation of tuning curve paramters _____________ 107 5.3.2 Statistical test for identifying head direction cells ____ 110 5.4 Standard methods for analysing a population of HD cells ___________________________________________ 113 5.5 Non-standard methods for analysing a population of HD cells ___________________________________________ 117 5.5.1 Kernel density estimates ______________________ 119 5.5.2 Statistical analysis of multimodal distributions ______ 123 5.6 Discussion and future directions __________________ 125 Chapter 6 Landmark feature processing by head direction cells 129 6.1 Background and rationale _______________________ 129 6.2 Methods and hypothesis ________________________ 131 6.2.1 Experimental procedure _______________________ 131 6.2.2 Hypothesis _________________________________ 133 6.3 Data analysis _________________________________ 136 6.3.1 Preferred firing direction shift analysis ____________ 137 6.3.2 Nonparametic density estimation ________________ 139 6.3.3 Circular summary statistics _____________________ 139 6.3.4 Inferential statistics ___________________________ 140 6.3.5 Cell response classification ____________________ 141 6.3.5.1 Bayesian analysis __________________________ 142 6.3.6 Co-rotation analysis __________________________ 143 6.3.7 Tuning curve characteristics ____________________ 144 4 6.4 Properties of PoS and RSC HD cell tuning curves ____ 145 6.5 Results of two cue card experiments _______________ 146 6.5.1 Subjects and cell numbers _____________________ 147 6.5.2 Are HD cells controlled by external room cues? _____ 148 6.5.3 Does brain area and cue type affect landmark control? _________________________________________ 149 6.5.4 Does the magnitude of cue rotation affect landmark control? _________________________________________ 150 6.5.5 Is there landmark control and discrimination for each cue type? ___________________________________________ 151 6.5.5.1 Bayesian estimates for cell response categories ___ 155 6.5.5.2 Vertical-horizontal __________________________ 159 6.5.5.3 Vertical-horizontal-polarity ____________________ 160 6.5.5.4 Top-bottom _______________________________ 161 6.5.5.5 Right-left _________________________________ 162 6.5.5.6 Black-black _______________________________ 163 6.5.5.7 Comparisons between cue types _______________ 164 6.6 Co-rotation activity in HD cell ensembles ___________ 167 6.7 Histology ____________________________________ 168 6.8 Discussion ___________________________________ 169 Chapter 7 Configural landmark processing by head direction cells ______________________________________________ 174 7.1 Background and rationale _______________________ 174 7.2 Methods _____________________________________ 177 7.2.1 Cue control protocol __________________________ 178 7.3 Data analysis _________________________________ 180 7.4 Results of the standard sessions __________________ 182 7.5 Results of the shuffle sessions ___________________ 184 7.5.1 Landmark processing of the standard cue configuration _____________________________________ 184 5 7.5.2 Landmark processing of the shuffled cue configuration _____________________________________ 186 7.6 Histology ____________________________________ 189 7.7 Discussion ___________________________________ 190 Chapter 8 General discussion and conclusion ______________ 195 References ____________________________________________ 201 6 DECLARATION I, Yave Roberto Lozano Navarro, confirm that the work presented in this thesis is my own. Where information has been derived from other sources, I confirm that this has been indicated in the thesis. 7 ACKNOWLEDGEMENTS Pursuing a doctoral degree in Neuroscience has been one of the great challenges in my life which would not have been possible without the encouragement of my parents Araceli and Roberto and my sister Heidi who have supported me unconditionally throughout my education. To my uncle Francisco, without whom I would not have been I able to cover the remaining tuition to enrol in UCL. To my supervisor, Kate Jeffery who has mentored, guided and supported me before and during the PhD, providing me with academic and personal advice, allowing me to persevere and succeed in the challenging field of behavioural electrophysiology. To my secondary supervisor, Frances Edwards for taking the time to review my upgrade report and guiding me on writing a thesis. To the scholarship from the Mexican National Council of Science and Technology, CONACYT (313254) which enabled me to study at a world’s leading research university in neuroscience. To the Medical Research Council grant G1100669, “A neuronal model of memory-integrative processing in the retrosplenial head direction system” which funded the work that I carried out. To all the former and past member of the Institute of Behavioural Neuroscience (IBN) who have been both colleagues and friends during the arduous years of graduate school. Special thanks to Robin and Liz who trained me in single-unit recording and my lab brothers Amir, Giulio, Jonathan, Laurenz, Shaz and Pierre- Yves who have been a source of both friendship and continuous help during the long days at the IBN. To Meghan, who recorded the rats that are described in Chapter 7. Special thanks to Miguel, whose statistical expertise and programming experience helped me to tackle the difficult problem of analysing circular data. To Josh for reviewing several chapters of this thesis and being a source of continuous discussion. To Caswell, for taking the time to discuss