Periodic Reporting for period 1 - VisHipMem (At first glance: How saccades drive communication between the visual system and the hippocampus during memory formation)
Reporting period: 2015-05-01 to 2017-04-30
The project’s aim is to understand how eye movements and brain activity are coordinated, to enable efficient memory encoding of visual information. We investigated this by simultaneously recording brain activity and eye movements from participants performing a memory task. Experiment 1 provided evidence for the memory-related coordination of brain oscillations and eye movements, indicating a mechanistic role of brain oscillations in coordinating the encoding of visual information during natural viewing. Experiment 2 revealed the impact of eye movements on brain metabolism in the hippocampus in relation to memory formation, as well as on the communication between task-relevant brain areas. Together, the findings answer basic questions about the interplay between eye movements and brain activity during memory formation.
The results of the project close a gap in understanding how visual information is processed during natural viewing and how information is transferred in the brain from the visual to the memory domain. Crucially, they provide insight into how these processes affect memory formation. Human memory is a topic of major public interest due to its core function in the human mind. Demographic change and aging, intimately related to the complex of dementia and Alzheimer’s disease, are one of the biggest challenges to today’s society. The findings of the present project advance the comprehension of the biological foundations of human memory, by investigating the neuronal basis of information processing and memory formation.
-Implementation of experimental paradigm, assembling stimuli and coding procedures for Experiment 1 and 2.
-Acquisition of pilot data ( Experiment 1 and 2).
-Acquisition of participants for data collection ( Experiment 1 and 2).
-MEG/fMRI data acquisition and recordings.
-MEG/fMRI data and joint analyses and results.
-Preparation for publication, publication, and presentation of results at international conferences.
Experiment 1 showed that that eye movements are locked to the phase of ongoing brain oscillations prior to a saccade. Importantly, this coordination predicted successful memory encoding. Engagement of task-relevant brain areas reflected effective vision to memory mapping. Experiment 2 revealed that eye movements modulated the memory-related brain activity in the hippocampus. Moreover, saccade-related functional connectivity between visual cortex and the hippocampus modulated subsequent memory performance.
Exploitation and dissemination
Saccade-triggered MEG activity during memory formation. Tübingen MEG Symposium 2015, Tübingen, Germany
Saccadic eye movements are phase-locked to posterior alpha oscillations during successful memory formation – evidence from MEG and intracranial data. Biomag 2016, Seoul, South Korea
Saccadic eye movements are phase-locked to posterior alpha oscillations during successful memory formation – evidence from MEG, fMRI and intracranial data. SfN 2016, San Diego, USA
Saccadic eye movements are phase-locked to posterior alpha oscillations and modulate neural communication during memory formation – evidence from MEG, fMRI and intracranial data. CNS 2017, San Francisco, USA
Saccades phase-locked to alpha oscillations in the occipital and medial temporal lobe enhance memory encoding. T. Staudigl, E. Hartl, S. Noachtar, C. F. Doeller, O. Jensen. bioRxiv 158758; doi: https://doi.org/10.1101/158758
Saccades phase-locked to alpha oscillations in the occipital and medial temporal lobe enhance memory encoding (under review). T. Staudigl, E. Hartl, S. Noachtar, C. F. Doeller, O. Jensen.
Hexadirectional signals during exploration of visual space in human MEG data (in prep.). T. Staudigl, et al.
Saccade-triggered fMRI reveals effective communication during memory formation (in prep). T. Staudigl et al.