You are invited to join the Clinical Vision Science Technical Group for a series exploring retinal physiology. The first session in this series will feature a talk from Dr. Morven Cameron from Western Sydney University exploring dopamine release in the mammalian retina.

The neuromodulator dopamine coordinates crucial brain functions such as voluntary movement, motivation and reward-related behaviors. In the retina, dopamine is released in response to light and plays an important role in light adaptation, as well as the growth and development of the eye. Release of dopamine originates in “dopaminergic” (DA) amacrine cells that reside in the inner nuclear layer and give rise to a dense plexus of dendrites and axons in the OFF sublamina of the inner plexiform layer as well as processes that extend to the outer plexiform layer. Light responses have been recorded in these cells via electrophysiology that originates from all three photoreceptor classes (rods, cones, and ipRGCs); however, Dr. Cameron will report that it is rod photoreceptors that are the prime drivers of light-induced dopamine release and that release of dopamine is not correlated with cell activity. 

Dr. Cameron uses various transgenic animals and chemogenetic tools to show that activation of ipRGCs is neither necessary nor sufficient to drive dopamine release despite a clear synaptic input from these cells to DA amacrines. These data suggest that a fundamental mechanism of dopamine release is likely quite different from that of conventional neurotransmitters. The dopaminergic system of the retina, while operating in a similar mechanistic way, is a smaller and more defined circuit that is ideal for examining the mechanisms of dopamine release in the CNS.

Subject Matter Level: Intermediate - Assumes basic knowledge of the topic

What You Will Learn: 

• About the dopaminergic system in the retina and what it does.
• Which photoreceptors contribute to the release of dopamine.
• Some hypotheses about the fundamental mechanisms of dopamine release.

Who Should Attend: 

• Those interested in retinal circuitry and photoreceptor function (in vivo). 
• Neuroscientists studying dopamine is other parts of the brain.
• Those interested in subjects related to retinal dopamine including light adaptation, myopia and diagnosis of central disorders (such as Parkinson's) using the retina.

About the Presenter: Morven Cameron from Western Sydney University

Dr Morven Cameron completed her PhD with Prof Robert Lucas at Manchester University in 2008 on retinal circadian rhythmicity. She then emigrated to Australia where she worked as a postdoc for Bionic Vision Australia on electrical stimulation of retinal neurons at Western Sydney University (WSU). In 2012 she was awarded a DECRA fellowship from the Australian Research Council to investigate gap junction connectivity in the mammalian retina. Following this fellowship, she was appointed to Lecturer (now Senior Lecturer) in Anatomy and Cell Biology at WSU. Her lab has an interest in the photoreceptors and circuits driving neuromodulator release in the retina, and intraretinal signalling of intrinsically photosensitive ganglion cells (ipRGCs) and their impact on rod and cone function. Dr Cameron’s lab does a variety of techniques including electroretinogram, LC-MS analysis of neuromodulator release, pupillometry, patch-clamp electrophysiology and immunohistochemistry.