Prof. Dr. Katharina Henke

 

Main Goals, Keywords

We work in the field of cognitive neuroscience. Our goal is to elucidate the psychological mechanisms and the neural correlates of memory formation, consolidation and retrieval. To this aim, we examine healthy individuals and neurological patients with focal brain lesions.

These are our current research projects:

1. Role of the human hippocampal formation in conscious and unconscious encoding, consolidation and retrieval of flexible associations. In particular: Is there an unconscious form of episodic memory?
2. Role of sleep stages and sleep parameters in the consolidation of consciously and unconsciously acquired memories
3. Role of hippocampus in creativity, insight and problem solving

Group Members

1 professor, 1 postdoc and 3 Ph.D. students (Patrizio Colella, Simone Duss, Simon Ruch)

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). Moreover, unconscious encoding affects the success of subsequent conscious encoding when the same, similar or different material is given for conscious learning. This influence of encoding across levels of consciousness was mediated by the hippocampal formation. We are currently examining patients with hippocampal damage to find out about the necessity of hippocampal integrity for unconscious encoding and retrieval. So far, our results support the notion of an unconscious form of episodic memory.

We also study the consolidation of consciously and unconsciously acquired memories in healthy individuals during daytime naps using polysomnographic recordings in the sleep laboratory. To boost the process of memory consolidation and for the study of encoding of new information during sleep, we apply acoustic stimulation during certain sleep stages. Finally, we are examining the role of human hippocampus in creative problem solving and insight both in healthy subjects and in patients with hippocampal damage.

Future Projects

A future project concerns the role of sleep stages in the consolidation of consciously and nonconsciously acquired memories. We measure brain activity with EEG and fMRI during encoding, sleep, and retrieval to reveal the functional neuroanatomy of memory encoding, consolidation, and retrieval. In order to enhance the natural process of memory consolidation during sleep, we apply external auditory cues to trigger memory consolidation to achieve a better retrieval performance.

Techniques and Equipment

• Behavioral techniques of experimental psychology (Department of Psychology, University of Bern)
• Functional and structural magnetic resonance imaging (Department of Diagnostic and Interventional Neuroradiology, University Hospital Bern; and Institute for Biomedical Engineering, University and ETH Zurich)
• Sleep polysomnography (Center of Sleep Medicine, Department of Neurology, University Hospital Bern)
• Neurological patients with focal lesions (Departments of Neurology, University Hospital Bern; and Department of Neurology, University Hospital Zurich)

Selected Publications

• Ruch S, Markes O, Duss SB, Oppliger D, Reber TP, Koenig T, Mathis J, Roth C, Henke K. Sleep stage II contributes to the consolidation of declarative memories. Neuropsychologia. 2012 Aug;50(10):2389-96. Epub 2012 Jun 27.
• Reber TP, Luechinger R, Boesiger P, Henke K. Unconscious relational inference recruits the hippocampus. J Neurosci. 2012 May 2;32(18):6138-48.
• Reber TP, Henke K. Integrating unseen events over time. Conscious Cogn. 2012 Jun;21(2):953-60. Epub 2012 Mar 17.
• Reber TP, Henke K. Rapid formation and flexible expression of memories of subliminal word pairs. Front Psychol. 2011;2:343. Epub 2011 Nov 22.

Selected Lectures, Seminars, Colloquia

Biological Psychology II. Lecture series for Bachelor students, each winter term, University of Bern. Cognitive neuroscience seminars for Master students, each term, University of Bern. Research seminar for graduate and undergraduate students, each term, University of Bern.

Funding

Swiss National Science Foundation

URL

http://www.apn.psy.unibe.ch/content/team/henke