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Research group Tebartz van Elst / Nickel

Visual Neuroscience
Research group leader: Prof. Dr. Ludger Tebartz van Elst
Phone: +49 (0)761 270 - 65010
Email: tebartzvanelst@uniklinik-freiburg.de

PD Dr. Kathrin Nickel
Phone: +49 (0)761 270 – 65010
Email: kathrin.nickel@uniklinik-freiburg.de

Secretariat: Frau Scheld
Phone: +49 (0)761 270 - 65290
Visual lab coordinator: Evelyn Friedel, M.Sc.
Phone: +49 (0)761 270 – 69081
Email: evelyn.friedel@uniklinik-freiburg.de
Group members: Prof. Dr. Dieter Ebert (MD)
PD Dr. Dominique Endres (MD)
Dr. Lisa Werner (MD)
Rita Werden (MD)
Dr. rer. nat. Simon Maier (biologist)
Céline Schmelz (MD student)
Hannah-Tabea Hahn (MD student)
Mirjam Schäfer (MD student)
Cooperation partners: PD Dr. rer. nat. Sven Heinrich (Eye Center, Medical Center, University of Freiburg, Head of the Section for Functional Vision Research)
Prof. Dr. Michael Bach (Eye Center, Medical Center, University of Freiburg)
PD Dr. Emanuel Bubl (Saarland University hospital)

Research focus

The question for valid biomarkers is of great importance in neuropsychiatric research. In this area, we focus on the retina, as an easily accessible and ontogenetic part of the brain, containing important neurotransmitters like dopamine. In many mental disorders, e.g. depression or schizophrenia, alterations in the systemic function of the dopaminergic system are assumed. Since the retinal signals are mainly modulated by dopaminergic activity, the visual integrity might be a valid method to investigate the integrity of the systemic function of the dopaminergic system in the brain.

To examine the retina, we apply two investigative tools:

1. Functional analysis with the electroretinogram (ERG)
The electroretinogram (ERG) is a diagnostic test to measure the electrical activity of different retinal cells, similar to an “ECG” of the heart. Depending on the type of stimulus, different cells can be tested for their function.

2. Structural analysis with the optical coherence tomography (OCT)
The OCT is and imaging technique similar to sonography, where light instead of sound is used to generate two- and three- dimensional pictures of the retina and its different cell layers, allowing thickness and volume measurements.
Because the PERG responses mostly origin from the retinal nerve fiber layer, we are especially interested in the thickness measurement of this structure.

Thickness measurement of the retinal nerve fiber layer around the papilla.

Current state of our research

In previous studies we detected that patients suffering from depression show a significant reduction in the PERG signals compared to healthy controls. Based on the alterations at the retinal level, we were able to distinguish depressed patients from healthy controls with high sensitivity and specificity. Furthermore, we could demonstrate that the PERG signal normalized after remission from depression. With regard to the question of objective biomarkers in neuropsychiatry, the processes at the retinal level (measured with the PERG) could represent a valid biomarker for depressive states in humans.

Currently, our research group focuses on the investigation of the specificity of this signal in different neuropsychiatric disorders (depression, bipolar disorder, schizophrenia, ADHD and autism) and in response to various therapeutic interventions (medication, psychotherapy, ECT etc.). Moreover, we are currently testing the suitability of a new portable device to measure the flash-ERG which would allow the application in clinical routine. Finally, by comparing both approaches (ERG and OCT), we aim to investigate possible relations between functional and structural changes of the retina.

Research projects

Recently completed:

  • Assessment of pattern-ERG in depression
  • Normalization of pattern-ERG alterations after remission from depression
  • Elevated retinal background noise in ADHD
  • Normalization of increased retinal background noise after ADHD treatment
  • Normal visual acuity and electrophysiological contrast gain in patients with autism spectrum disorder


  • Optimization of the pattern-ERG stimulus parameters for the application in clinical routine
  • Investigation of the correlation of functional and structural retinal alterations in patients with depression applying new approaches e.g. Flash-ERG with the RETeval® system and Optical Coherence Tomography (OCT)
  • Functional and structural investigation of the retina in schizophrenia with the Optical Coherence Tomography (OCT)

Planned Projects:

  • Effect of nicotine on dopaminergic modulated visual signal transmission
  • Pharmacological effect of psychiatric medication on the retinal signals and structure
  • Identification of the timing when pattern-ERG alterations normalize in the course of the remission from depression

Selected publications

  • Werner AL, Tebartz van Elst L, Ebert D, Friedel E, Bubl A, Clement HW, Lukačin R, Bach M, Bubl E. 2019. Normalization of Increased Retinal Background Noise after ADHD Treatment: A Neuronal Correlate. Schizophrenia Research. doi.org/10.1016/j.schres.2019.04.013.
  • Tebartz van Elst L, Bach M, Blessing J, Riedel A, Bubl E. 2015. Normal Visual Acuity and Electrophysiological Contrast Gain in Adults with High-Functioning Autism Spectrum Disorder. Frontiers in Human Neuroscience 9: 460. doi.org/10.3389/fnhum.2015.00460.
  • Bubl E, Dörr M, Philipsen A, Ebert D, Bach M, Tebartz van Elst L. 2013. Retinal Contrast Transfer Functions in Adults with and without ADHD. Edited by Mark W. Greenlee. PLoS One 8 (5): e61728. doi.org/10.1371/journal.pone.0061728.
  • Bubl E, Ebert D, Kern E, Tebartz van Elst L, Bach M. 2012. Effect of Antidepressive Therapy on Retinal Contrast Processing in Depressive Disorder. The British Journal of Psychiatry 201 (2): 151–58. doi.org/10.1192/bjp.bp.111.100560.
  • Bubl E, Kern E, Ebert D, Bach M, Tebartz van Elst L. 2010. Seeing Gray When Feeling Blue? Depression Can Be Measured in the Eye of the Diseased. Biological Psychiatry 68 (2): 205–8. doi.org/10.1016/j.biopsych.2010.02.009.
  • Bubl E, Tebartz van Elst L, Gondan M, Ebert D, Greenlee MW. 2009. Vision in Depressive Disorder. The World Journal of Biological Psychiatry: The Official Journal of the World Federation of Societies of Biological Psychiatry 10 (4 Pt 2): 377–84. doi.org/10.1080/15622970701513756.