A ground squirrel retina cross-section labeled with antibodies against recoverin (green), calretinin (red) and PKA (blue).

About our work

The long-term goal of our research is to study the mammalian retina as a model for the central nervous system (CNS) -- to understand how it functions in physiological conditions, how it is formed, how it breaks down in pathological conditions, and how it can be repaired.

We have focused on two research themes: 1) Photoreceptor structure, synapse, circuits, and development, 2) Hibernation and metabolic adaptations in the retina and beyond. As the first neuron of the visual system, photoreceptors are vital for photoreception and transmission of visual signals.

We are particularly interested in cone photoreceptors, as they mediate our daylight vision with high resolution color information. Diseases affecting cone photoreceptors compromise visual functions in the central macular area of the human retina and are thus most detrimental to our vision. However, because cones are much less abundant compared to rods in most mammals, they are less well studied. We have used the ground squirrel (GS) as a model system to study cone vision, taking advantage of their unique cone-dominant retina. In particular, we have focused on short-wavelength sensitive cones (S-cones), which are not only essential for color vision, but are also an important origin of signals for biological rhythm, mood and cognitive functions, and the growth of the eye during development. We are studying critical cone synaptic structures – synaptic ribbons, the synaptic connections of S-cones, and the development of S-cones with regard to their specific connections. These works will provide knowledge of normal retinal development and function, which can also be extended to the rest of CNS. In addition, such knowledge will benefit the development of optimal therapeutic strategies for regeneration and repair in cases of retinal degenerative disease.

Many neurodegenerative diseases, including retinal diseases, are rooted in metabolic stress in neurons and/or glial cells. Using the same GS model, we aim to learn from this hibernating mammal, which possesses an amazing capability to adapt to the extreme metabolic conditions during hibernation. By exploring the mechanisms of such adaptation, we hope to discover novel therapeutic tactics for neurodegenerative diseases.

ground squirrel

The ground squirrel (Spermophilis tridecemlineatus) is one of the rare mammals whose retina is cone-dominated and resembles the fovea of human retina. Researchers with the NEI’s Unit on Retinal Neurophysiology are using this animal model to study the cone visual system including retinal circuits for color vision. Credit: Dr. Brett Szmajda (UNSW)

Selected publications

Nadal-Nicolás FM*, Kunze VP, Ball JM, Peng BT, Krishnan A, Zhou G, Dong L, Li W* (2020). True S-cones are concentrated in the ventral mouse retina and wired for color detection in the upper visual field. Elife 9:e56840

Ou J, Ball JM, Luan Y, Zhao T, Miyajishima J, Xu Y, Chen J, Merriman D, Xie Z, Mallon BS, Li W* (2018) iPSCs from a hibernator provide a platform for studying cold adaptation and its potential medical applications Cell 173(4):851-863

Fan JG, Jia L, Li Y, Ebrahim S, May-Simera H, Wood L, Morell RJ, Liu PH, Lei JQ, Kachar B, Belluscio L, Qian H, Li T, Li W*, Wistow GJ*, Dong LJ* (2017) Maturation arrest in early postnatal sensory receptors by deletion of the miR-183/96/182 cluster in mouse. PNAS 114(21):E4271-E4280

Mehta B, Snellman J, Chen S, Li W*, and Zenisek D* (2013) Synaptic ribbons influence the size and frequency of miniature-like evoked postsynaptic currents. Neuron 77(3):516-527

Chen S, Li W* (2012) A color-coding amacrine cell may provide a blue-Off signal in a mammalian retina. Nature Neuroscience 15(7):954-956

Li W*, Chen S, DeVries SH* (2010) A fast rod photoreceptor signaling pathway in the mammalian retina. Nature Neuroscience 13(4):414-416.


Reviews and chapters

Angueyra J and Li W, Subcortical color pathways in mammals, The Senses (2nd Edition), in press

Li W (2020) Ground squirrel - A cool model for a bright vision. Semin Cell Dev Biol S1084-9521(19):30117

Ou J, Rosa S, Berchowitz LE, Li W (2019) Induced pluripotent stem cells as a tool for comparative physiology: lessons from the thirteen-lined ground squirrel. J Exp Biol 222

Miyagishima K, Grünert U, Li W (2014) Processing of S-cone Signals in the Inner Plexiform Layer of the mammalian retina. Visual Neuroscience 31(2):153-163


Retinal Neuroplysiology Section Journal Covers

Journal covers

NEI Retinal Neurophysiology Section staff enjoy a picnic.

NEI Retinal Neurophysiology Section Staff

Retinal Neurophysiology Section key staff

Key staff table
Name Title Email Phone
Juan Angueyra, Ph.D. Postdoctoral Fellow juan.angueyra-aristizabal@nih.gov 301-402-5459
John Ball, Ph.D. Staff Scientist john.ball2@nih.gov 301-402-1924
Vincent Kunze, Ph.D. Postdoctoral Fellow vincent.kunze@nih.gov 301-402-1340
Wei Li, Ph.D. Senior Investigator liwei2@nei.nih.gov 301-496-6669
Kiyoharu Miyagishima, Ph.D. Staff Scientist kiyoharu.miyagishima@nih.gov 301-435-5123
Francisco Nadal-Nicolas, Ph.D. Postdoctoral Fellow francisco.nadal-nicolas@nih.gov 301-402-1340
Laura Patak Postbac Fellow laura.patak@nih.gov 301-402-1927
Xiyuan Ping Visiting Student xiyuan.ping@nih.gov 301-402-1340
Fengyu Qiao, Ph.D. Biologist qiaof@nei.nih.gov 301-402-2595
Abhishek Sengupta Predoctoral Fellow abhishek.sengupta@nih.gov
Steve Stashef, M.D., Ph.D. Visiting Scientist steven.stasheff@nih.gov 301-402-1924

News from this lab

Ground squirrel curled up in a nest

NIH researchers develop 'hibernation in a dish' to study how animals adapt to the cold

May 3, 2018

Researchers at the National Eye Institute have discovered cellular mechanisms that help the 13-lined ground squirrel survive hibernation.
Last updated: September 10, 2020