Cognitive Neuroscience of Memory and Consciousness

Our research focus

We work in the field of cognitive neuroscience. Our goal is to elucidate the psychological mechanisms and the neural correlates of conscious and unconscious learning, consolidation and retrieval. To this aim, we examine healthy individuals and neurological patients using behavioral methods, functional magnetic resonance imaging, positron emission tomography, electroencephalography, and polysomnography.

Our findings suggest that the human hippocampal formation specializes in the rapid establishment of new sensory, conceptual, spatial, and temporal relations based on consciously or unconsciously experienced episodes. We study unconscious encoding in the wake state using subliminal (masked) visual learning material and in the unconscious state of deep sleep using acoustic learning material. Findings indicate that the hippocampal formation mediates the rapid encoding of new relations when encoding is conscious and unconscious, in the waking state and during deep sleep. Sleep-learning appears to be bound to peaks of slow oscillations of deep sleep. Unconscious encoding influences the success of subsequent conscious encoding of the same, similar and different learning material. Patients with hippocampal damage exhibit a decrease in both conscious and unconscious relational encoding and retrieval.

We currently test for a potential advantage of unconscious over conscious information processing in situations where complex information needs to be processed and evaluated. In an ongoing research project, we are examining the role of hippocampal sharp-wave ripples in sleep-learning and wake-learning using recordings of human intracranial EEG. Our research informs models of information processing, memory models and sleep theories.

Techniques

  • Behavioral techniques of experimental psychology
  • Neuropsychological and experimental examination of neurological patients (Departments of Neurology, University Hospital Bern; Department of Neurology, University Hospital Zurich)
  • Functional and structural magnetic resonance imaging (MRI)
    (Department of Diagnostic and Interventional Neuroradiology, University Hospital Bern)
  • Positron emission tomography (PET)
  • Electroencephalography (EEG)
  • intracranial EEG recordings in patients with epilepsy
  • Sleep polysomnography
  • Auditory closed-loop stimulation of the sleep slow oscillation

Keywords

Memory, consciousness, sleep-wake, information processing, subliminal, hippocampus, neuroimaging