I am working on the vertebrate retina, with a main focus on the bird and mouse retina. Currently my work is focused on three major topics:

• Circuitry for light-dependent magnetoreception in the bird retina
• Interaction partners of the putative magnetosensor molecule cryptochrome 4 in the retina
• Gap junctions in the mouse retina and retinal pigment epithelium

Retinal circuitry for light-dependent magnetoreception in the bird

We are studying which neuronal cell types and pathways in the bird retina are involved in the processing of magnetic signals. Likely, magnetic information is detected in cryptochrome-expressing photoreceptors and leaves the retina through ganglion cell axons that project via the thalamofugal pathway to Cluster N, a part of the visual wulst essential for the avian magnetic compass. Thus, we aim to elucidate the synaptic connections and retinal signaling pathways from putatively magnetosensitive photoreceptors to thalamus-projecting ganglion cells in migratory birds using neuroanatomical and electrophysiological techniques.

Interaction partners of Cryptochrome 4 in the avian retina

Magnetoreception likely involves Cryptochrome 4 which is expressed in the double cone photoreceptors of the European robin, a night-migratory songbird. In collaboration with other groups, we identify and characterize potential interaction partners and study their localization in the avian retina.

Gap junctions in the mouse retina and retinal pigment epithelium

Electrical synapses (gap junctions) permit fast transmission of electrical signals and passage of metabolites by means of channels, which directly connect the cytoplasm of adjoining cells. A functional gap junction channel consists of two hemichannels (one provided by each of the cells), each comprised of a set of six protein subunits, termed connexins. These building blocks exist in a variety of different subtypes, and the connexin composition determines permeability and gating properties of a gap junction channel, thereby enabling electrical synapses to meet a diversity of physiological requirements.

In the retina and the retinal pigment epithelium, various connexins are expressed in different cell types. We study the cellular distribution of different connexins as well as the modulation induced by transmitter action or change of ambient light levels, which leads to altered electrical coupling properties. We are also interested in exploiting them as therapeutic avenue for retinal degeneration diseases.

Current projects:

Principal Investigator in the Cluster of Excellence NaviSense. 

Principal Investigator in the DFG-funded Collaborative Research Center SFB1372: Magnetoreception and Navigation in Vertebrates.

Principal Investigator in the ERA-Net (EU/BMBF-funded) project RETHEALTHSI.

Former projects:

DFG-funded Research Training Group Molecular Basis of Sensory Biology

DFG-funded project (in collaboration with apl. Prof. Dr. Ulrike Janssen-Bienhold): Einfluss von Horizontalzellen auf die Lichtantworten retinaler Ganglienzellen

DFG-funded project (in collaboration with apl. Prof. Dr. Ulrike Janssen-Bienhold): Electrical synapses in rod and cone pathways of the mouse retina

European commission-funded project (within switchBoard - an Innovative Training Network (ITN) funded by the European Commission's Horizon 2020 programme): Role of bipolar cell-to-bipolar cell and bipolar cell-to-amacrine cell coupling in the mouse retina