Kwoon Y Wong

The visual system not only enables us to see but also performs nonimage-forming tasks such as the pupillary light reflex, synchronizing daily (i.e. circadian) rhythms with the light/dark cycle, and regulating hormone secretion. Nonimage-forming vision is mediated by intrinsically photosensitive retinal ganglion cells (ipRGCs), a subset of retinal output neurons that contains the light-sensing molecule melanopsin. My lab investigates three questions regarding ipRGC physiology:

1) How do ipRGCs respond to light? Using human subjects as well as rodents, my lab is investigating how ipRGCs respond to light stimuli of various durations, intensities, wavelengths, and temporal patterns. We are also examining the molecular and cellular mechanisms underlying ipRGCs' unique light responses. The results will help develop better phototherapy for jet lag and seasonal affective disorder, and healthier electric lights.

2) How do the various types of ipRGCs differ functionally? My lab is studying their electrophysiological diversity to better understand their different functional roles.

3) To what extent do ipRGCs signal to other retinal cells, and what does this signaling do? For over a century, retinal ganglion cells were thought to signal only to higher visual centers of the brain. Surprisingly, we have shown that ipRGCs transmit light-evoked responses to several types of retinal amacrine cells. We are analyzing the circuits and functions of such retrograde signaling.

More recently, we began to collaborate with three other Ophthalmology labs to investigate: 1) an innovative strategy for retinal prosthesis; 2) using photoacoustic imaging to quantify visual-evoked hemodynamic responses in mouse brain; and 3) using glia-derived neurons to treat retinal degeneration.