1. Knowing where and getting there: a human navigation network Maguire, e
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: Contextual Elements
James Guse
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 Differences in age of subjects is very important
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 Women Men Bilateral advantage hypothesis
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. Duke Nukem 3D! ... ? Simulation of a 3D environment
James Guse
Simulation of a 3D environment
A 2D maze projected into 3D
Shading and textural details deep enough to convince participants.

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

10. Resolution Two dimensions integrated into three.
James Guse
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

11. Experimental Validity
Nicole Neil
Experimental Validity

12. Virtual Environments Pros Cons High ecological validity
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

13. Ecological Validity Primate Comparisons: Nicole Neil 1 2 3 4
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 1 2 3 4
(Matsmura, Nishijo, Tamura, Eifuku, Endo, & Ono, 1999)

14. Virtual Environments Pros Cons High ecological validity
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

15. Participants Stationary
Nicole Neil
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)

16. Participants Stationary
Nicole Neil
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)

17. Participants Stationary
Nicole Neil
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)

18. Hippocampal Lateralization
Mudra Bhatt
Hippocampal Lateralization

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

20. Right Hippocampus
Mudra Bhatt
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),

21. Left Hippocampus
Mudra Bhatt
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),

22. Contextual Elements The role of the hippocampus in spatial navigation:
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?

23. O’Keefe and Nadel, 1978 The Hippocampus as a Cognitive Map
Molly O’Brien
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
New information about role
A – hippocampus is neural substrate of cognitive map; mediates perceptions of allocentric space (absolute space representation with world-based coordinates)
Damage = severe deficits in navigation that required use of mental map (opposed to those solved using simple response strategies)
recordings showed cells fired selectively in particular location of environment
B – amnesic patients with damage to hippocampus and areas in temporal lobe showed impairment in declarative memory functions = role of hippocampus in declarative memory
O’Keefe, J. and Nadel, L., The Hippocampus as a Cognitive Map, Clarendon Press, Oxford.

24. Two Distinct Camps Emerge ...
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
CMV similar to O’Keefe and Nadel’s argument
RLV proposes that we encode relationships between environmental stimuli and create episodic memories, and that spatial representations are a natural result, but not an essential part of the system
Knierim, J.J. (2003). Hippocampus and memory: can we have our place and fear it too? Neuron, 37 (3),

25. Where does our study fit in?
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:

26. So, which theory? Cognitive Map View Relational Learning View
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
explain
hard to tell what came first, as theories make similar predictions; when making observations, difficult to rule out either theory
Interpretations of data tend to reflect the preconceived notions – many results interpreted as in favour of one theory can easily be interpreted in terms of the other as well

27. Where Now? Molly O’Brien
if there is such difficulty deciding which is correct, where do we go from here?

28. Future Directions
Molly O’Brien
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),

29. Conclusions
Main points from the commentary presentation

30. 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

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