Main goals

1. Role of hippocampus in conscious and unconscious learning, consolidation, and retrieval
2. Sleep parameters that influence the consolidation of information that has been learned with and without consciousness before going to sleep
3. Limits of unconscious information processing during sleep and in the awake state

Group members and their position

1 professor,
1 assistant (Simon Ruch),
3 PhD-students (Sergej Wüthrich, Marc Züst, Else Schneider), 1 technical assistant (Sandra Röthlisberger)

Previous and current research

Our findings suggest that the human hippocampal formation specializes in the rapid establishment of new conceptual associations between items in memory. Importantly, we found that the hippocampal formation mediates the rapid encoding of new associations even when encoding (and later retrieval) were carried out without conscious awareness of encoding (and retrieval). We examined patients with hippocampal damage to find out about the necessity of hippocampal integrity for unconscious relational encoding and retrieval.

We also study the consolidation of consciously and unconsciously acquired memories in healthy individuals during daytime naps using polysomnographic recordings in the sleep laboratory. We are testing for learning DURING sleep. Our research aims at redefining memory systems at both the neural and psychological level.

Future projects

We will study unconscious spatial and temporal associative encoding and retrieval in a new project. Space and time are important aspects of episodic memories. We ask whether new what-where-when memories can be formed from moment to moment if the learning material is presented invisibly (subliminally).

Techniques / methods

Functional and structural magnetic resonance imaging, EEG und sleep polysomnography, neurological patients (neuropsychology), eye-tracking, behavioral assessment.

Equipment

– Behavioral techniques of experimental psychology (Department of Psychology, University of Bern)
– EEG (Department of Psychology, University of Bern)
– Functional and structural magnetic resonance imaging (Department of Diagnostic and Interventional Neuroradiology, University Hospital Bern; Institute for Biomedical Engineering, University and ETH Zurich)
– Sleep polysomnography (Center of Sleep Medicine, De-partment of Neurology, University Hospital Bern)
– Neurological patients (Department of Neurology, University Hospital Bern; Department of Neurology, University Hospital Zurich

Selected publications

Henke K, Reber TP, Duss SB (2013). Integrating events across levels of consciousness. Frontiers in Behavioral Neuroscience, Jun 14;7:68. doi: 10.3389/fnbeh.2013.00068.
Ruch, S., Markes, O., Duss, S.B., Reber, T.P., Koenig, T., Mathis, J., Roth, C., Henke, K. (2012). Sleep stage II contrib-utes to the consolidation of episodic memories. Neuropsychologia, 50, 2389-2396.
Reber, T.P., Luechinger, R., Boesiger, P., Henke, K. (2012). Unconscious relational inference recruits the hippocampus. Journal of Neuroscience, 32, 6138-6148.
Henke, K. (2010). A model for memory systems based on processing modes rather than consciousness. Nature Reviews Neuroscience, 11, 523-532.

Selected lectures, seminars, colloquia

Lecturer “Biological Psychology II”, Lecture series for Bachelor Students, each Fall Term, University of Bern, Switzerland.
Instructor “Genetics and epigenetics in psychology”, course for Master Students, Spring Term 2013, University of Bern, Switzerland.

Funding

Swiss National Science Foundation
Center for Cognition, Learning and Memory, University of Bern, Switzerland