The information available via our senses is restricted and to varying degrees ambiguous. It needs to be disambiguated and continuously
interpreted in order to construct stable and reliable percepts. The discrimination between reality and illusion is thus to a large degree based on
the capability of our perceptual system. Ambiguous figures are paradigmatic examples in this context. The observed stimulus, e.g. a Necker
cube, is maximally ambiguous, and percepts become unstable and alternate repeatedly between possible outcomes although the underlying
stimulus stays unchanged. We use this phenomenon of perceptual instability to study the psycho-physical relations and altered states of consciousness.
How long lasts a moment? The answer to this question is important for the understanding of perceptual processes, of consciousness and
also of altered states of consciousness. The estimated duration of a moment - about 3 s - corresponds to the duration of a temporal
Gestalt in music, to the duration of a linguistic element and also to the average duration of perceptual stability ("dwell time") of
an ambiguous figure. In the xx Achtsamkeitsmeditation meditators focus on the present moment in order to achieve an altered state of
consciousness with increased attention and high emotional control. It is assumed that the duration of a moment will be extended in such
an altered state of consciousness. Confirmation comes from experienced meditators. They show longer ambiguous figure dwell times
compared to non-meditating
The recently presented Necker-Zeno-model of bistable perception presents a mathematical relation between dwell times and two other basic
time scales of cognitive relevance: (a)the order threshold, (i.e. the minimal temporal distance of about 30 ms between two successive
stimuli to identify their order) and (b) the duration of about 300 ms between stimulus onset and perceptual awareness of the stimulus.
This model predicts that the temporal extension of a moment correlates with a deceleration of perceptual awareness and/or a shortening of the
order threshold (Atmanspacher et al. 2008). In an EEG study on the perception of ambiguous figures with meditators and non-meditator controls
we test these model predictions by focusing on the temporal patterns of event related potentials that are specific to the perception of
ambiguous figures (Kornmeier & Bach 2012).
Perception of ambiguous figures is unstable and alternates between different interpretations. Tiny figural changes can disambiguate an
ambiguous stimulus and stabilize its percept. Recently, we found an ERP ambiguity effect, consisting of two event-related potentials, a
fronto-central P200 and a parieto-central P400, with the following features: (a) the ERP amplitudes increase monotonously with decreasing
stimulus ambiguity, (b) the ERP latencies and spatial distributions are very similar across highly different visual categories (geometry,
motion and semantics, see Figure below).
We interpret these effects in the context of the following model: Our perceptual system weights the sensory information with concepts from
perceptual memory in order to construct stable and reliable percepts. A probabilistic inference unit estimates the reliability of the perceptual
constructs and the P200 and P400 amplitudes reflect the result. In a series of current projects we test the generalization of the ERP ambiguity
effect across modalities (visual, auditory and tactile). Further we plan to compare brain sources of the P200 and P400 signatures between
Perceptions result from a weighting of exogenous sensory information with endogenous memory concepts (see above). This weighting can
be biased in either direction, depending on the quality of the sensory information. Patients with Asperger Autism Spectrum Disorder put
more weight on sensory information and less weight on endogenous memorized concepts. In a cooperation project with the Clinic for
Psychiatry and Psychotherapy of the University Freiburg we study whether such perceptual differences between patients and healthy controls
are reflected in an altered ERP ambiguity effect (see above). We further plan a project where we compare the ERP ambiguity effect in
patients with Schizophrenia Spectrum Disorder and healthy controls.
Friedel E, Tebartz van Elst L, Schmelz C, Ebert D, Maier S, Endres D,
Goll P, Runge K, Bubl E, Kornmeier J, Bach M, Heinrich SP, Nickel K (submitted)
Reduced Pattern electroretinogram amplitudes in depression – Improved recording paradigm
Kornmeier J, Sosic-Vasic Z, Joos E (submitted) Spacing Learning Units affects both learn-ing and forgetting
Kornmeier J, Bhatia K, Joos E (in revision) Top down resolution of visual ambiguity – knowledge from the future or by footprints from the past?
Hecker L, Rupprecht R, Tebartz van Elst L, Kornmeier J (2021) ConvDip: A convolutional neural network for improved M/EEG Source Imaging.
Frontiers in Neuroscience 15. https://doi.org/10.3389/fnins.2021.569918
Joos E, Giersch A, Bhatia K, Heinrich SP, Tebartz van Elst L, Kornmeier J (2020) Using the perceptual past to predict the perceptual future influences the perceived present – a novel ERP paradigm
PLoS ONE 15(9): e0237663
Joos E, Giersch A, Hecker L, Schipp J, Tebartz van Elst L, Kornmeier J (2020) Large EEG effects are highly similar across Necker cubes, smileys and abstract stimuli.
PLoS ONE 15(5): e0232928
Staadt R, Philipp ST, Cremers J, Kornmeier J, Jancke D (2020) Seeing what was not explained away: Visual illusion based on predictive coding signals
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Neumann F, Oberhauser V, Kornmeier J (2020) How our nose helps us optimize learning while we sleep – from lab research to real life.
Scientific Reports 10, 1227
Kornmeier J, Friedel E, Hecker L, Schmidt S, Wittmann M (2019) What happens in the brain of meditators when perception changes but not the stimulus?
PLoS ONE 14(10): e0223843
Liaci E, Fischer A, Atmanspacher H, Heinrichs M, Tebartz van Elst L, Kornmeier J (2018) Positive and Negative Hysteresis Effects for the Perception of Geometric and Emotional Ambiguities.
PLoS ONE 13(9): e0202398
Sosic-Vasic Z, Hille K, Kröner J, Spitzer M, Kornmeier J (2018) When learning disturbs
memory – temporal profile of retroactive interference of learning on memory formation.
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Psychophysiology 53 (10), 1507-1523
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Schmidt-Mutter C, Giersch A (2016) Neurophysiological evidence of enhanced pain sensitivity in patients with schizophrenia. Scientific Reports 6, 22542, 1-10
Wernery J, Atmanspacher H, Kornmeier J, Candia V, Folkers G, Wittmann M (2015) Temporal processing in bistable perception of the Necker cube.
Perception 44(2), 157-168.
Kornmeier J. Mayer G. (2014) The alien in the forest OR when temporal context
dominates perception. Perception 43(11), 1270-1274.
Mayer G. & Kornmeier J. (2014). Rätselhafte Objekte auf den Bildern einer Wildkamera oder: die Tücken der Wahrnehmung.
Zeitschrift für Anomalistik Band 14, 7-24.
Kornmeier J. & Bach M. (2014). EEG correlates to perceptual reversals of Boring's ambiguous Old/Young Woman.
Perception 43(9), 950-962-A.
Kornmeier J., Wörner R., Riedel A. & Tebartz van Elst L. (2014). A different view on the
checkerboard? Alterations in early and late visually evoked EEG potentials in Asperger
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Kornmeier J., Spitzer M. & Sosic-Vasic Z. (2014). Very similar spacing-effect patterns in very different
learning/practice domains. PLoS ONE 9(3): e90656.
O'Shea R., Kornmeier J. & Roeber U. (2013). Predicting visual consciousness
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Kornmeier J. & Sosic-Vasic Z. (2012). Parallels between spacing effects during behavioural and cellular learning.
Frontiers in Human Neuroscience 6(203): 1-5.
Kornmeier J. & Bach M. (2012). Ambiguous figures - What happens in the brain if perception changes but not the stimulus.
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(low-level) and percept-related (high-level) EEG signatures early in occipital cortex.
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figures. In: Fechner Day 2010, ed. by A. Bastianelli and G. Vidotto, International Society for
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Psychophysiology 48: 547-558.
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Journal of Vision 9(1): 7, 1-10.
Kornmeier J., Hein CM. & Bach M. (2009). Multistable Perception: When bottom-up and top-down coincide.
Brain & Cognition 69: 138-147.
PD Dr. H. Atmanspacher (IGPP, Freiburg & Collegium Helveticum, Zürich, Schweiz)
Prof. M. Bach (Universitäts-Augenklinik, Freiburg)
Prof. M. Castelo-Branco (University of Coimbra, Portugal) /
PD Dr. T. Filk (Physik, Universität Freiburg)
Prof. G. Folkers (Collegium Helveticum, Zürich, Schweiz)
Dr. A. Giersch (Psychiatrie der Universität Strasbourg)
PD Dr. SP. Heinrich (Universitäts-Augenklinik, Freiburg)
Prof. R. O'Shea (Southern Cross University, Coffs Harbour, Australien)
Dr. Z. Sosic-Vasic (Psychiatrie der Universität Ulm)
Prof. M. Spitzer (Psychiatrie der Universität Ulm)
Prof. T. Stieglitz (Technische Fakultät der Universität Freiburg)
PD Dr. R. Roeber (Institut für Psychologie, Universität Leipzig)
Prof. L. Tebartz van Elst (Psychiatrie der Universität Freiburg)
PD Dr M. Wittmann (IGPP)