Zebrafish early vision in the context of its natural input
Application deadline: Dr Tom Baden and Prof. Leon Lagnado
Application deadline: 30 November 2015
Project Description
All visual systems are specialised to best serve an animal’s sensory niche1–3, yet how such
specialisations are achieved through phylogenetic and developmental adaptations are poorly
understood. This project will study these adaptations in the visual system of zebrafish.
Specifically, we will use two-photon functional imaging to survey how the visual systems of
both larval and adult zebrafish sample and process behaviourally meaningful natural stimuli
to ultimately drive behaviour. We will also build a robotic camera system capable of
realistically documenting the zebrafish natural world to guide stimulus design.
The retina breaks high-dimensional patterns of light modulated in space, time and wavelength
into parallel, feature selective pathways for transmission to the brain4. Retinal ganglion cells
(RGCs), the only retinal neurons that send information to the brain, inherit much of their
visual response selectivity in the retina’s ‘switchboard’, the inner plexiform layer5 (IPL).
Here, the presynaptic terminals of bipolar cells (BCs)5, the only neurons that relay the
photoreceptor (PR) signal into the inner retina, form complex synapses with amacrine cells
(ACs) and RGC dendrites. This BC/AC/RGC synapse is probably the most important yet
least understood computational locus of the circuit6. At the same time, BCs inherit their
excitatory drive directly from photoreceptors (PRs) at the so-called cone/rod-pedicle, a
computationally powerful feedback synapse. Both BC and PR presynaptic terminals, which
as populations represent the two most fundamental processing layers of the retina, are
optically accessible in vivo (zebrafish larva) and retinal explants7,8. By monitoring lightdriven activity in large populations of synaptic terminals of PRs and BCs it is possible to
systematically follow how the visual input is sequentially broken down and distributed into
parallel processing channels by the retinal network before it is forwarded to the brain9.
Presentation of stimuli designed to specifically probe prominent and behaviourally essential
aspects of the zebrafish natural world will allow linking identified principles to their
ecological purpose. Taken together, the approach will address how retinal computations
acknowledge the visual world of the larval and adult zebrafish.
Funding Notes
Apply for PhD in Neuroscience, September 2016 entry. Mention name of supervisor in
“suggested supervisor” section. In funding mention sponsored or seeking funding. In Award
details mention School of Life Sciences funded studentship. Include brief statement of
interest (upto 2 pages), CV, two academic references, UG/PG transcripts, IELTS/TOEFL
results if residing in EU. The studentship is for 3.5 years (full fee waiver, stipend Research
Council equivalent rate). Only full time Home/EU students will be accepted.
For further queries contact Tom Baden (Thomas.baden@uni-tuebingen.de)
References
1. Land, M. & Nilson, D.-E. Animal Eyes. (Oxford University Press, 2012).
2. Cronin, T. W., Johnsen, S., Marshall, N. J. & Warrant, E. J. Visual Ecology. (Princeton
University Press, 2014).
3. Baden, T. et al. A tale of two retinal domains: near-optimal sampling of achromatic
contrasts in natural scenes through asymmetric photoreceptor distribution. Neuron 80, 1206–
17 (2013).
4. Masland, R. H. The fundamental plan of the retina. Nat. Neurosci. 4, 877–86 (2001).
5. Euler, T., Haverkamp, S., Schubert, T. & Baden, T. Retinal Bipolar Cells: Elementary
Building Blocks of Vision. Nat. Rev. Neurosci. 15, 507–519 (2014).
6. Baden, T., Euler, T., Weckström, M. & Lagnado, L. Spikes and ribbon synapses in early
vision. Trends Neurosci. 36, 480–8 (2013).
7. Dreosti, E., Esposti, F., Baden, T. & Lagnado, L. In vivo evidence that retinal bipolar cells
generate spikes modulated by light. Nat Neurosci 14, 951–952 (2011).
8. Baden, T., Esposti, F., Nikolaev, A. & Lagnado, L. Spikes in Retinal Bipolar Cells PhaseLock to Visual Stimuli with Millisecond Precision. Curr. Biol. 21, 1859–1869 (2011).
9. Wässle, H. Parallel processing in the mammalian retina. Nat. Rev. Neurosci. 5, 747–57
(2004).
Related Subjects
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Evolution
Molecular Biology
Neuroscience / Neurology
Optical Physics
Zoology / Animal Science