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A Commentary Presented By:

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. James Guse. Presentation Format.

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A Commentary Presented By:

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  1. Knowing where and getting there: a human navigation networkMaguire, 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. James Guse Presentation Format • Introduction • Critique: • Subject Selection • Methodologies • Experimental Validity • Hippocampal Lateralization • Contextual Elements • Conclusion

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

  4. Age Richa Sharma • 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

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

  6. James Guse Methodologies

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

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

  9. James Guse 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

  10. Nicole Neil Experimental Validity

  11. Nicole Neil Virtual Environments Pros Cons • High ecological validity • High experimental control • Functional imaging possible during acquisition of spatial memories • Smaller field of view • Fixed distance from screen • Participants stationary

  12. Nicole Neil 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 activationacross both situations • Significantly more neurons fired in the real task as opposed to the virtual task 1 2 4 3 (Matsmura, Nishijo, Tamura, Eifuku, Endo, & Ono, 1999)

  13. Nicole Neil Virtual Environments Pros Cons • High ecological validity • High experimental control • Functional imaging possible during acquisition of spatial memories • Smaller field of view • Fixed distance from screen • Participants stationary

  14. Nicole Neil 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)

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

  16. Nicole Neil 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)

  17. Mudra Bhatt Hippocampal Lateralization

  18. Mudra Bhatt Right vs Left Hippocampus Right Hippocampus Left Hippocampus • Accuracy of navigation • Non-spatial navigation

  19. Mudra Bhatt 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), 1333-1340.

  20. Mudra Bhatt 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), 5983-5990.

  21. Molly O’Brien Contextual Elements 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?

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

  23. Molly O’Brien Two Distinct Camps Emerge ... Cognitive Map View Relational Learning View • 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 Knierim, J.J. (2003). Hippocampus and memory: can we have our place and fear it too? Neuron, 37 (3), 372-374.

  24. Molly O’Brien 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: http://www.cartoonstock.com/lowres/hsc4567l.jpg

  25. Molly O’Brien So, which theory? Cognitive Map View Relational Learning View • 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

  26. Molly O’Brien Where Now?

  27. Molly O’Brien Future Directions • Knierim (2003) suggests a more “systems-oriented” approach • Develop a greater wealth of knowledge regarding: • Information flow between hippocampus and surrounding areas • Input/output functions • Characterize computations performed by each Knierim, J.J. (2003). Hippocampus and memory: can we have our place and fear it too? Neuron, 37 (3), 372-374.

  28. Conclusions Main points from the commentary presentation

  29. Take Home Points! PROS CONS • 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

  30. 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.404-408. • GiuseppIara, 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),293-298. • Knierim, J. J. (2003). Hippocampus and Memory Can We Have Our Place and Fear It Too? Neuron , Vol.37(3), pp.372-374. • 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), 2381-2393 • 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.157-170.

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