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Asta K. Håberg Trondheim fMRI gruppe Department of Neuroscience

www.NTNU.no /fMRI. Human navigation abilities elucidated using functional MRI and virtual reality. Asta K. Håberg Trondheim fMRI gruppe Department of Neuroscience Norwegian University of Science and Technology (NTNU). Navigation. Memory test (objects-places-events ++)

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Asta K. Håberg Trondheim fMRI gruppe Department of Neuroscience

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  1. www.NTNU.no/fMRI Human navigation abilities elucidated using functional MRI and virtual reality Asta K. Håberg Trondheim fMRI gruppe Department of Neuroscience Norwegian University of Science and Technology (NTNU)

  2. Navigation • Memory test (objects-places-events ++) • Ecologically valid • Impaired navigation abilities present in • different disorders • (Alzheimer’s disease, neurodevelopmental disorders) • Used extensively in animal research • (translational potential)

  3. Medial temporal lobe with hippocampus Posterior (Back) Anterior (Front) Hippocampus

  4. Healthy Demented

  5. Example of VR environment ~62 m ~74 m

  6. Movement plots Start Target

  7. Navigation activates a network of cortical and subcortical regions Xu et al., 2010

  8. Size of the place fields along the hippocampal A-P axis Anterior- posterior axis of hippocampus

  9. Navigation RESEARCH QUESTIONS: 1. Different demands during navigation period gives rise to different activity? 2. Can we find evidence for a difference along the anterior-posterior axis of the hippocampus? 3. Are there differences between men and women? 4. What distinguishes successful and unsuccessful navigation?

  10. Navigation 1. Different demands during navigation period gives rise to different activity? 2. Can we find evidence for a difference along the anterior-posterior axis of the hippocampus? 3. Are there differences between men and women? 4. What distinguishes successful and unsuccessful navigation?

  11. Unaltered environment Landmarks removed

  12. 1. Different demands during navigation period gives rise to different activity? • - Hippocampal activity throughout the navigation period • only found in intact environment • Hippocampal activity highly specific for different periods • The specific demands of the different navigational periods affect the interaction of the hippocampus with other brain regions

  13. Navigation 1. Different demands during navigation period gives rise to different activity? 2. Can we find evidence for a difference along the anterior-posterior axis of the hippocampus? 3. Are there differences between men and women? 4. What distinguishes successful and unsuccessful navigation?

  14. 2. Can we find evidence for a difference along the anterior-posterior axis of the hippocampus? Spatial detail is represented by posterior hippocampus Spatial coherence (map like overview ) is represented in anterior hippocampus Functional segregation of the representation of space along hippocampus A-P axis

  15. Navigation 1. Different demands during navigation period gives rise to different activity? 2. Can we find evidence for a difference along the anterior-posterior axis of the hippocampus? 3. Are there differences between men and women? 4. What distinguishes successful and unsuccessful navigation?

  16. Success rate for reaching target, men and women

  17. Trajectory mapping 1st target landmark

  18. Differences in navigation strategy Men and women moved the same distance, but: Men picked shortcuts Men used a map-like representation of the environment Men were better at making correct judgments wrt distance and direction between objects

  19. During the entire navigation period men have more hippocampal activity than women Male>female Female>male

  20. In men hippocampal activity is accompanied by increase interaction with orbitofrotal cortex and precuneus

  21. 3. Are there differences between men and women? • Men and women use different navigation strategies • The male navigation strategy is more successful • Men use a map-like representation of space, and the direction and distance between objects are more correctly and precisely positioned. • The differences in navigation behavior is reflected in differences in hippocampal activity and hippocampal interaction with other brain regions.

  22. Navigation 1. Different demands during navigation period gives rise to different activity? 2. Can we find evidence for a difference along the anterior-posterior axis of the hippocampus? 3. Are there differences between men and women? 4. What distinguishes successful and unsuccessful navigation?

  23. BOLD signal time courses for successful and unsuccessful trials Anterior hippocampus Posterior hippocampus Target reached

  24. 4. What distinguishes successful and unsuccessful navigation? Navigational success seems particularly dependent on activation of the anterior (front) of the hippocampus

  25. Conclusions

  26. Acknowledgement PhD student Hallvard R. Evensmoen MD PhD JianXu Postdoc PhD Hanne Lehn Funding: NTNU, MI lab (Norwegian Research Council), Women in sciences grant (NTNU), Department of Radiology (St. Olav’s Hospital) Medical research student Carl WS Pintzka

  27. Thank you

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