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KNOWING WHERE AND GETTING THERE: A HUMAN NAVIGATION NETWORK MAGUIRE, E.A., BURGESS, N., DONNETT, J.G., FRACKOWIAK, R.S., FRITH, C.D. AND O'KEEFE, J. A.

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Presentation on theme: "KNOWING WHERE AND GETTING THERE: A HUMAN NAVIGATION NETWORK MAGUIRE, E.A., BURGESS, N., DONNETT, J.G., FRACKOWIAK, R.S., FRITH, C.D. AND O'KEEFE, J. A."— Presentation transcript:

1 KNOWING WHERE AND GETTING THERE: A HUMAN NAVIGATION NETWORK MAGUIRE, E.A., BURGESS, N., DONNETT, J.G., FRACKOWIAK, R.S., FRITH, C.D. AND O'KEEFE, J. A Commentary Presented By: Molly O’Brien, Nicole Neil, Mudra Bhatt, Richa Sharma and James Guse

2 Presentation Format  Introduction  Critique:  Subject Selection  Methodologies  Experimental Validity  Hippocampal Lateralization  Contextual Elements  Conclusion James Guse

3 The effect of age and gender on neural substrates involved in spatial navigation Subject Selection Richa Sharma

4 Age  Differences in age of subjects is very important  Effects of aging on the hippocampus  Direct effect on navigation  In the study, average age given and a 60 minute training session  Different age groups = Different training requirements Richa Sharma

5 Gender  Women  Egocentric  Landmarks  Right parietal and prefrontal area  Men  Allocentric  Geometric cues, topographic constellation  Parahippocampal and right hippocampus  Bilateral advantage hypothesis Richa Sharma

6 Methodologies James Guse

7 Duke Nukem 3D!... ? Simulation of a 3D environment A 2D maze projected into 3D Shading and textural details deep enough to convince participants. James Guse

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9 PET Scanning How do the Pixels become Voxels? Regional Blood Flow Half Life of (15)O Effects on the perception of space? James Guse

10 Resolution  Two dimensions integrated into three.  'Resolving' power maintained by replication  MRI resolution: 2mmx1mmx1mm – but it's been smoothed Losing noise always looses data.  Statistical Parametric Mapping no longer just the average number of events in one voxel.  Given the averages overlain on averages, we can't say just where one cause of blood use ends and another begins.  Problems with the space – these voxels just won't fit!  Overall good enough for the gross anatomical James Guse

11 Experimental Validity Nicole Neil

12 Virtual Environments  High ecological validity  High experimental control  Functional imaging possible during acquisition of spatial memories  Smaller field of view  Fixed distance from screen  Participants stationary ProsCons Nicole Neil

13 Ecological Validity  Primate Comparisons:  Single cell recordings from hippocampus of monkeys  Monkeys either: REAL: Navigate a cab using a joystick to receive a reward VIRTUAL: Move a pointer on an LCD screen to receive a reward  Similar patterns of activation across both situations  Significantly more neurons fired in the real task as opposed to the virtual task (Matsmura, Nishijo, Tamura, Eifuku, Endo, & Ono, 1999) Nicole Neil

14 Virtual Environments  High ecological validity  High experimental control  Functional imaging possible during acquisition of spatial memories  Smaller field of view  Fixed distance from screen  Participants stationary ProsCons Nicole Neil

15 Participants Stationary  Vestibular Contributions to Spatial Memory:  Participants asked to imagine/move on one leg of a path, then turn, and imagine/move on a second leg of a turn (Klatzky, Loomis, Beall, Chance, & Golledge, 1998) Nicole Neil

16 Participants Stationary  Vestibular Contributions to Spatial Memory:  Real world condition, participants either: 1) Heard description and imagined 2) Viewed experimenter walk the path 3) Walked it blindfolded  Virtual condition, participants either 1) Optic flow for leg (1) presented, experimenter turned participant, optic flow for leg (2) presented 2) Optic flow presented for both legs and turn (Klatzky, Loomis, Beall, Chance, & Golledge, 1998) Nicole Neil

17 Participants Stationary  Vestibular Contributions to Spatial Memory:  Participants who made a physical turn made fewer errors in reorienting  Vestibular information important for updating spatial system (Klatzky, Loomis, Beall, Chance, & Golledge, 1998) Nicole Neil

18 Hippocampal Lateralization Mudra Bhatt

19 Right vs Left Hippocampus  Accuracy of navigation  Non-spatial navigation Right HippocampusLeft Hippocampus Mudra Bhatt

20 Right Hippocampus  Activity correlates with the amount of accurate navigation  Relationship between accurate navigation and the amount of blood flow in right hippocampus  Right hippocampus contains a vector that points toward the goal location O’Keefe, J., Burgess, N., Donnett, J., Jeffery, K. & Maguire, E. (1998) Place cells, navigational accuracy, and the human hippocampus. Philosophical Transactions: Biological Sciences, 353 (1373), Mudra Bhatt

21 Left Hippocampus  Left anterior hippocampus activity correlates with spatial binding and goal-directed navigation.  mediates specific component of spatial navigation Binding an object to its spatial location  Left posterior hippocampus activity correlates navigation performance Cornwell, B., Johnson, L., Holroyd, T., Carver, F, and Grillon, C. (2008) Human Hippocampal and Parahippocampal Theta during Goal –Directed Spatial Navigation Predicts Performance on a Virtual Morris Water Maze. The Journal of Neuroscience, 28(23), Mudra Bhatt

22 The role of the hippocampus in spatial navigation: - What did Maguire et al have to build upon? - What are some of the major viewpoints? - Where does the study by Maguire et al fit in? - Where is the field headed? Contextual Elements Molly O’Brien

23 O’Keefe and Nadel, 1978  The Hippocampus as a Cognitive Map  Role of the hippocampus in the: a) Psychological representation of space i. Animals with hippocampal damage in navigation tasks ii. Recordings from hippocampal cells in freely moving rats b) Context dependent memory i. Amnesic memory system dissociations O’Keefe, J. and Nadel, L., The Hippocampus as a Cognitive Map, Clarendon Press, Oxford. Molly O’Brien

24 Two Distinct Camps Emerge...  Hippocampus acts as spatial mapping system  Organize and remember items and events of experience  Hippocampus is a more general learning system  Spatial representations naturally result, but are not essential part Cognitive Map ViewRelational Learning View Knierim, J.J. (2003). Hippocampus and memory: can we have our place and fear it too? Neuron, 37 (3), Molly O’Brien

25 Where does our study fit in?  Maguire et al showed that...  “Not only is the right hippocampus more active during navigation than trail-following...”  Navigation requires cognitive map  “... but the more accurate the navigation, the more active it is.”  Recalling specific destinations and successful pathways  Episodic memory function Retrieved from: Molly O’Brien

26 So, which theory?  Subjects generate an overall cognitive map of the city  Map facilitates the memory of landmarks and routes in relation to one another  Subjects remember the landmarks and routes  Spatial relationships are a natural result of this memory Cognitive Map ViewRelational Learning View Molly O’Brien

27 Where Now? Molly O’Brien

28 Future Directions  Knierim (2003) suggests a more “systems-oriented” approach  Develop a greater wealth of knowledge regarding: 1. Information flow between hippocampus and surrounding areas 2. Input/output functions 3. Characterize computations performed by each Knierim, J.J. (2003). Hippocampus and memory: can we have our place and fear it too? Neuron, 37 (3), Molly O’Brien

29 Main points from the commentary presentation Conclusions

30 Take Home Points!  In vivo analysis  High ecological validity  Relevance to previous research, and provides base of support for future directions  Age and gender effects on neural activation during navigation  Actual data resolution fuzzy  Participants stationary during tasks  Role of left hippocampus in spatial navigation PROSCONS

31 References  George Gron, A. P. (2000). Brain activation during human navigation: gender-different neural networks as substrate of performance. Nature Neuroscience, Vol. 3(4), pp  Giusepp Iara, L. P. (2008). Age differences in the formation and use of cognitive maps. Behavioural Brain Research.  Klatzky, R.L., Loomis, J.M., Beall, A.C., Chance, S.S., & Golledge, R.G. (1998). Spatial updating of self-position and orientation during real, imagined, and virtual locomotion. Psychological science, 9(4),  Knierim, J. J. (2003). Hippocampus and Memory Can We Have Our Place and Fear It Too? Neuron, Vol.37(3), pp  Matsmura, N., Nishijo, H., Tamura, R., Eifuku, S., Endo, S., & Ono, T. (1999). Spatial- and Task- dependent neuronal responses during real and virtual translocation in the monkey hippocampal formation. The Journal of Neuroscience, 19(6),  Nadel, J. O. (1978). The Hippocampus as a Cognitive Map.  Ruben C. Gur, D. A. (2000). An fMRI study of Sex Differences in Regional Activation to a Verbal and Spatial Task. Brain and Language, Vol. 74, pp


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