Research groups
Retinal Neurobiology Research Group II.
Béla Völgyi (associate professor) E-mail: volgyi@gamma.ttk.pte.hu
Tel.: +36 72-503-600 (ext: 29045)
Research interest

The vertebrate retina has a layered structure in which somata of photoreceptors, interneurons and the output ganglion cells are located in the distalmost outer nuclear layer, the inner nuclear layer in the middle and the ganglion cell layer in the inner retina, respectively. Among the interneurons, bipolar cells relay information from photoreceptors to ganglion cells, whereas horizontal and amacrine cells provide inhibitory synapses to transversally signaling photoreceptors, bipolar and ganglion cells. Excitation occurs via glutamate release by photoreceptors, bipolar cells and ganglion cells whereas inhibition takes place by the release of GABA or glycine from horizontal and amacrine cells. Apart from chemical synapses electrical synaptic interactions take place in the retina as well. Very characteristic interactions are established by ganglion and/or amacrine cells whose electrical synapses correlate ganglion cell activity to generate a population code. As each ganglion cell population creates a feature movie of the visual world, each of these movies in turn streamed through parallel signaling pathways towards visual centers in the brain. Parallel signaling is maintained at the level of both the thalamus and the visual cortex. Since most ganglion cells maintain electrical synapses with their ganglion and amacrine cell neighbors gap junction mediated synchronous activity must be impinged in the information transmitted by parallel visual pathways. Our research focus is to examine how electrical synapse mediated synchronization contributes to the spike code, how the flow of synchronized information through these parallel feature channels contributes to activity of neuron populations in the visual cortex and how visually guided behavior mediated by synchronized signals passed through each of these parallel feature pathways. Our long-term plan is to utilize collected data on the above topic for machine/computer vision, robotics, drone technology and perhaps in retinal prosthetic devices as well.

Clinical relevance

Over 940 million people suffer in various forms of vision loss worldwide. Visual impairments have considerable economic costs both directly due to the cost of treatment and indirectly due to decreased ability to work. Our long-term goal is to establish a frame-work describing various signaling mechanisms retinal ganglion cells utilize to encrypt each of the features in our visual environment. Beyond the obvious benefits this project may provide for neuroscience and computer vision, the dataset will also be used to generate algorithms suitable for epiretinal implants. 

Tools
60 channels Multichannels System MEA recording system
Axon 200B based patch-clamp electrophysiology rig
BioRad PCR
Leica CM1860 cryostat
MTI DAGE extracellular recording system
Narishige micromanipulators
NIKON FN1 elektrophysiology microscopes
Sutter P-87 micropipette puller
TILL photonics Ca++-imaging systems
Methods
Confocal Laser Scanning Microscopy (CLSM)
GMO and transgenic techniques
Immunhistochemistry
In vitro Ca++ imaging
Patch-clamp electrophysiology
Real-Time Polymerase Chain Reaction (RT-PCR)
Single electrode and multielectrode extracellular recording
Single-cell intracellular electrophysiology
Superresolution microscopy
Visual stimulation and optogenetics
Western blot
Laboratory members
Representative publications
Characterization of connexin36 gap junctions in the human outer retina. Kantor O., Benko Z., Enzsoly A., David C., Naumann A., Nitschke R., Szabo A., Palfi E., Orban J., Nyitrai M., Nemeth J., Szel A., Lukats A., Volgyi B.
Brain Structure and Function (206/221(6): 2963-2984.)
DOI | PubMed | Scopus
Connexin36 expression in the mammalian retina: A multiple-species comparison. Kovacs-Oller T., Debertin G., Balogh M., Ganczer A., Orban J., Nyitrai M., Balogh L., Kantor O., Volgyi B.
Frontiers in Cellular Neuroscience (2017/11(9): 65.)
DOI | PubMed | Scopus
Gap junction-mediated death of retinal neurons is connexin and insult specific: A potential target for neuroprotection. Akopian A., Atlasz T., Pan F., Wong S., Zhang Y., Volgyi B., Paul D.L., Bloomfield S.A.
Journal of Neuroscience (2014/34(32): 10582-10591.)
DOI | PubMed | Scopus
Gap junctional coupling in the vertebrate retina: Variations on one theme? Volgyi B., Kovacs-Oller T., Atlasz T., Wilhelm M., Gabriel R.
Progress in Retinal and Eye Research (2013/34: 1-18.)
DOI | PubMed | Scopus
Gap junctions are essential for generating the correlated spike activity of neighboring retinal ganglion cells. Volgyi B., Pan F., Paul D.L., Wang J.T., Huberman A.D., Bloomfield S.A.
PLoS ONE (2013/8(7): e69426.)
DOI | PubMed | Scopus
Funding

Hungarian Brain Research Program (grant number: KTIA_NAP_13-2-2015-0008)

European Union and the State of Hungary, co-financed by the European Social Fund in the framework of ‘National Excellence Program’ (grant number: EFOP-3.6.1.-16-2016-00004)

European Union and the State of Hungary, co-financed by the European Social Fund in the framework of ‘National Excellence Program’ (grant number: TÁMOP-4.2.4.A/2-11/1-2012-0001) 

Tempus Public Fundation (grant number: PPP 152214)