Investigating hippocampal activation elicited by watching indistinct motion stimuli N Dalal1, E Fraedrich1, V L Flanagin1, S Glasauer2 |
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1Graduate School of Systemic Neurosciences, Ludwig Maximillian University, Munich, Germany |
| Almost for a decade now there is an inconclusive debate about the role of hippocampus in visuo-spatial perception. So far, related studies have focused on static images as visual input. In real life, however, we are confronted mostly with dynamic visual scenes, which may or may not be novel. In previous fMRI experiments, we compared brain activation elicited by meaningful visual motion stimuli depicting movement through a virtual tunnel and indistinct, meaningless visual motion stimuli, achieved through spatio-temporal phase scrambling of the same stimuli [Fraedrich et al, 2012, J Cogn Neurosci, 24(6), 1344-57]. The indistinct visual motion stimuli evoked bilateral hippocampal activation, whereas the corresponding meaningful stimuli did not. In the present follow-up study, we investigate whether temporal changes in image content are responsible for continuous hippocampal activation by manipulating the temporal characteristics of our indistinct visual motion stimuli. Since static phase-scrambled images have not been reported to activate the hippocampus, we expect a graded increase of hippocampal activation with increasing high-frequency content in the temporal dynamics of the visual stimuli. This would support our hypothesis that the observed hippocampal BOLD response is caused by memory retrieval related to the indistinct scenes. Acknowledgements: DFG (GRK 1091 and GSN) and BMBF. |
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