Education

B. Pharm.
School of Pharmacy, London University
Ph.D
School of Pharmacy, London University
Postdoctoral Training
University of Texas Medical School at Houston
Postdoctoral Training
Washington University

Areas of Interests

Research Interests

Simply put, the goal of my research is to describe the neuronal circuitry of the retina. The organization of the mammalian retina is certainly complex but it is not chaotic. Although there are many cell types, most adhere to a relatively constant morphology and they are distributed in non-random mosaics. Furthermore, each cell type ramifies at a characteristic depth in the retina and makes a stereotyped set of synaptic connections. In other words, these neurons form a series of local circuits across the retina. The next step is to identify the simplest and commonest of these repeating neural circuits. They are the building blocks of retinal function. If we think of it in this way, the retina is a fabulous model for the rest of the CNS.

We are interested in identifying specific circuits and cell types that support the different functions of the retina. For example, there appear to be specific pathways for rod and cone mediated vision. Rods are used under low light conditions and rod circuitry is specialized for high sensitivity when photons are scarce (when you’re out camping, starlight). The hallmark of the rod-mediated system is monochromatic vision. In contrast, the cone circuits are specialized for high acuity and color vision under relatively bright or daylight conditions.

Individual neurons may be filled with fluorescent dyes under visual control. This is achieved by impaling the cell with a glass microelectrode using a 3D micromanipulator. We are also interested in the diffusion of dye through coupled neuronal networks in the retina. The dye filled cells are also combined with antibody labeling to reveal neuronal connections and circuits. This triple-labeled material may be viewed and reconstructed in 3 dimensions by multi-channel confocal microscopy. We have our own confocal microscope facility in the department and timeslots are available to students in my lab.

Publications

Publication Information

Recent Papers
  • O’Brien JJ, Li W, Pan F, Keung JW, O’Brien J and Massey SC (2006) Coupling between A-type horizontal cells is mediated by connexin 50 gap junctions in the rabbit retina. J. Neuroscience 26(45):11624-36.
  • Pan F and Massey SC (2007) Rod and Cone Input to Horizontal Cells in the Rabbit Retina. J. Comp Neurol. 500:815-31 and cover.
  • Pan F, Mills SL and Massey SC (2007) Screening of gap junction antagonists on dye coupling in the rabbit retina Visual Neurosci. 24(4):609-18.
  • Hoshi H, Liu W-L, Massey SC, and Mills, SL (2009) ON input to the OFF layer: Bipolar Cells which break the Stratification Rules of the Mammalian Retina. J Neuroscience. 29(28):8875-83 and cover.
  • Kothmann WW, Massey SC and O’Brien J (2009) Dopamine-Stimulated Dephosphorylation of Connexin 36 Mediates AII Amacrine Cell Uncoupling. J.Neuroscience 29(47):14903-11.
  • Hoshi H, Tian L-M, Massey SC, and Mills SL (2011) Two Distinct Types of ON Directionally-Selective Ganglion Cells in the Rabbit Retina. J. Comp. Neurol. 519(13):2509-21 and cover
Recent Reviews
  • Massey SC (2005) Functional Anatomy of the Mammalian Retina In: Retina, Fourth Edition (Editor-In-Chief: Stephen J. Ryan MD), Volume One, Basic Science and Inherited Retinal Disease (Editor: David R. Hinton MD) pp 43-82, 47 figures.
  • Massey SC (2008) Circuit Functions of Gap Junctions in the Mammalian Retina. In: AI Basbaum, A Kaneko, GM Shepherd and G Westheimer, (eds.), The Senses: A Comprehensive Reference, Vol 1, Vision I; R Masland and TD Albright (eds.), Academic Press, San Diego, 2008 pp 457-472.
  • Massey SC (2009) Connexins in the Mammalian Retina. A Harris and D Locke (eds.), Connexins: A Guide Humana Press, New York, NY 2009 pp 391-411.