Applied Mathematics Colloquium

IMA Wham! Workshop Group Presentation

Location

Mathematics/Psychology : 104

Date & Time

March 28, 2014, 12:00 pm1:00 pm

Description

Title:  Modeling the Melanopsin Phototransduction Cascade

Abstract:  Melanopsin is a recently discovered photopigment found in intrinsically photosensitive retinal  ganglion cells (ipRGCs). It is involved in non-image forming vision, including circadian photoentrainment, the pupillary light reflex, and seasonal affective disorder. When light activates the photopigment, a phototransduction cascade commences, which produces an electrical signal that is sent to the brain. Light adaptation is the ability of the visual system to adjust its performance according to the ambient level of illumination. To describe melanopsin’s phototransduction and adaptation pathways, we developed a deterministic and stochastic mathematical model  that  describes the pathway. Model parameters of the activation and deactivation were determined by fitting the model results to experimental calcium imaging data collected from transfected human embryonic kidney cells expressing the melanopsin gene as well as electrophysiological data collected from ipRGCs. Mathematical simulations of the single flash response and the light-adapted response produce results consistent with those seen in the experimental data.


This work was funded by NSF for Undergraduate Biology and Mathematics Research Training, NSF IOSO721608 and NEI R01Y019053 to P. Robinson. The stochastic model development was funded by the IMA Wham! Workshop. The talk is a joint talk with Phyllis Robinson (Biology), Hye-Won Kang (Math and Stat), Kathleen Hoffman (Math and Stat) and the visiting IMA Wham! group: Katie Williams (U Arizona), Christine Hamlet (Tulane), and Erika Camacho (Arizona State and MIT).