Presentation on theme: "Knowing where and getting there: a human navigation network Maguire, e"— Presentation transcript:
1Knowing 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
2Presentation Format Introduction Critique: Contextual Elements James GuseIntroductionCritique:Subject SelectionMethodologiesExperimental ValidityHippocampal LateralizationContextual ElementsConclusion
3Richa SharmaSubject SelectionThe effect of age and gender on neural substrates involved in spatial navigation
4Age Differences in age of subjects is very important Richa SharmaDifferences in age of subjects is very importantEffects of aging on the hippocampusDirect effect on navigationIn the study, average age given and a 60 minute training sessionDifferent age groups = Different training requirements
5Gender Women Men Bilateral advantage hypothesis Richa SharmaWomenEgocentric Landmarks Right parietal and prefrontal areaMenAllocentric Geometric cues, topographic constellation Parahippocampal and right hippocampusBilateral advantage hypothesis
9PET Scanning How do the Pixels become Voxels? Regional Blood Flow James GuseHow do the Pixels become Voxels?Regional Blood FlowHalf Life of (15)OEffects on the perception of space?
10Resolution Two dimensions integrated into three. James GuseTwo dimensions integrated into three.'Resolving' power maintained by replicationMRI 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
12Virtual Environments Pros Cons High ecological validity Nicole NeilVirtual EnvironmentsProsConsHigh ecological validityHigh experimental controlFunctional imaging possible during acquisition of spatial memoriesSmaller field of viewFixed distance from screenParticipants stationary
13Ecological Validity Primate Comparisons: Nicole Neil 1 2 3 4 Single cell recordings from hippocampus of monkeysMonkeys either:REAL: Navigate a cab using a joystick to receive a rewardVIRTUAL: Move a pointer on an LCD screen to receive a rewardSimilar patterns of activation across both situationsSignificantly more neurons fired in the real task as opposed to the virtual task1234(Matsmura, Nishijo, Tamura, Eifuku, Endo, & Ono, 1999)
14Virtual Environments Pros Cons High ecological validity Nicole NeilVirtual EnvironmentsProsConsHigh ecological validityHigh experimental controlFunctional imaging possible during acquisition of spatial memoriesSmaller field of viewFixed distance from screenParticipants stationary
15Participants Stationary Nicole NeilVestibular 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)
16Participants Stationary Nicole NeilVestibular Contributions to Spatial Memory:Real world condition, participants either:Heard description and imaginedViewed experimenter walk the pathWalked it blindfoldedVirtual condition, participants eitherOptic flow for leg (1) presented, experimenter turned participant, optic flow for leg (2) presentedOptic flow presented for both legs and turn(Klatzky, Loomis, Beall, Chance, & Golledge, 1998)
17Participants Stationary Nicole NeilVestibular Contributions to Spatial Memory:Participants who made a physical turn made fewer errors in reorientingVestibular information important for updating spatial system(Klatzky, Loomis, Beall, Chance, & Golledge, 1998)
19Right vs Left Hippocampus Mudra BhattRight vs Left HippocampusRight HippocampusLeft HippocampusAccuracy of navigationNon-spatial navigation
20Right HippocampusMudra BhattActivity correlates with the amount of accurate navigationRelationship between accurate navigation and the amount of blood flow in right hippocampusRight hippocampus contains a vector that points toward the goal locationO’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),
21Left HippocampusMudra BhattLeft anterior hippocampus activity correlates with spatial binding and goal-directed navigation.mediates specific component of spatial navigationBinding an object to its spatial locationLeft posterior hippocampus activity correlates navigation performanceCornwell, 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),
22Contextual Elements The role of the hippocampus in spatial navigation: Molly O’BrienContextual ElementsThe 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?
23O’Keefe and Nadel, 1978 The Hippocampus as a Cognitive Map Molly O’BrienThe Hippocampus as a Cognitive MapRole of the hippocampus in the:Psychological representation of spaceAnimals with hippocampal damage in navigation tasksRecordings from hippocampal cells in freely moving ratsContext dependent memoryAmnesic memory system dissociationsNew information about roleA – 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 environmentB – amnesic patients with damage to hippocampus and areas in temporal lobe showed impairment in declarative memory functions = role of hippocampus in declarative memoryO’Keefe, J. and Nadel, L., The Hippocampus as a Cognitive Map, Clarendon Press, Oxford.
24Two Distinct Camps Emerge ... Molly O’BrienTwo Distinct Camps Emerge ...Cognitive Map ViewRelational Learning ViewHippocampus acts as spatial mapping systemOrganize and remember items and events of experienceHippocampus is a more general learning systemSpatial representations naturally result, but are not essential partCMV similar to O’Keefe and Nadel’s argumentRLV 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 systemKnierim, J.J. (2003). Hippocampus and memory: can we have our place and fear it too? Neuron, 37 (3),
25Where does our study fit in? Molly O’BrienWhere 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 thenavigation, the more active it is.”Recalling specific destinations andsuccessful pathwaysEpisodic memory functionRetrieved from:
26So, which theory? Cognitive Map View Relational Learning View Molly O’BrienSo, which theory?Cognitive Map ViewRelational Learning ViewSubjects generate an overall cognitive map of the cityMap facilitates the memory of landmarks and routes in relation to one anotherSubjects remember the landmarks and routesSpatial relationships are a natural result of this memoryexplainhard to tell what came first, as theories make similar predictions; when making observations, difficult to rule out either theoryInterpretations 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
27Where Now? Molly O’Brien if there is such difficulty deciding which is correct, where do we go from here?
28Future DirectionsMolly O’BrienKnierim (2003) suggests a more “systems-oriented” approachDevelop a greater wealth of knowledge regarding:Information flow between hippocampus and surrounding areasInput/output functionsCharacterize computations performed by eachKnierim, J.J. (2003). Hippocampus and memory: can we have our place and fear it too? Neuron, 37 (3),
29ConclusionsMain points from the commentary presentation
30Take Home Points! PROS CONS In vivo analysis High ecological validity Relevance to previous research, and provides base of support for future directionsAge and gender effects on neural activation during navigationActual data resolution fuzzyParticipants stationary during tasksRole of left hippocampus in spatial navigation
31ReferencesGeorge Gron, A. P. (2000). Brain activation during human navigation: gender-different neural networks as substrate of performance. Nature Neuroscience , Vol. 3(4), ppGiusepp 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), ppMatsmura, 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