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
Presentation Format Introduction Critique:
Subject Selection Methodologies Experimental Validity Hippocampal Lateralization
Contextual Elements Conclusion
James Guse
The effect of age and gender on neural substrates involved in spatial navigation
Subject Selection
Richa Sharma
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
Gender Women
Egocentric Landmarks Right parietal and prefrontal area
Men Allocentric Geometric cues, topographic
constellation Parahippocampal and right hippocampus
Bilateral advantage hypothesis
Richa Sharma
Methodologies
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.
James Guse
PET Scanning How do the Pixels
become Voxels? Regional Blood Flow Half Life of (15)O Effects on the
perception of space?
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
James Guse
Experimental Validity
Nicole Neil
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
Pros Cons
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 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
1 2
3 4
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
Pros Cons
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)
Nicole Neil
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 either1) 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
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
Hippocampal Lateralization
Mudra Bhatt
Right vs Left Hippocampus
Accuracy of navigation
Non-spatial navigation
Right Hippocampus Left Hippocampus
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.
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.
Mudra Bhatt
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
O’Keefe and Nadel, 1978
The Hippocampus as a Cognitive Map Role of the hippocampus in the:
a) Psychological representation of spacei. Animals with hippocampal damage in navigation tasksii. Recordings from hippocampal cells in freely moving rats
b) Context dependent memoryi. Amnesic memory system dissociations
O’Keefe, J. and Nadel, L., 1978. The Hippocampus as a Cognitive Map, Clarendon Press, Oxford.
Molly O’Brien
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 View Relational Learning View
Knierim, J.J. (2003). Hippocampus and memory: can we have our place and fear it too? Neuron, 37 (3), 372-374.
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
Molly O’Brien
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 View Relational Learning View
Molly O’Brien
Where Now? Molly O’Brien
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 functions3. 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.
Molly O’Brien
Main points from the commentary presentation
Conclusions
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
PROS CONS
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.
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),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.