View
67
Download
1
Category
Preview:
Citation preview
The Heterogeneity of intrinsically photosensitive Retinal Ganglion Cells
(ipRGCs)
Ben Loreto & Kris Cronise
OutlineipRGCsFunctionHeterogeneity of ipRGCsAnatomy and PhysiologyModelFuture GoalsReferences and
Acknowledgements
ipRGCsClassical
Photoreceptors (rods and cones)
Horizontal Cells,Bipolar Cells,
And Amacrine Cells
Ganglion Cells
ipRGCs = intrinically photosensitive retinal
ganglion cells
Source: http://www.skidmore.edu/~hfoley/images/Retina.jpg
Melanopsin Amination here
Heterogeneity of ipRGCs5 major classes of
ipRGCs
Each classified by certain differences in anatomy and physiology
Adapted from: http://www.nature.com/nature/journal/v415/n6871/images/415493a-f1.2.jpg
Soma SizeSoma size = Size of cell body
Both figures modified from: Schmidt et al. (2011)
Dendritic Stratification and FieldDendritic Stratification = Where signal is received in the retinaDendritic field = Amount of area covered by dendrites
Both figures modified from: Ecker. (2011)
Molecular IdentityMolecular Identity = Level of Gene ExpressionMelanopsin gene = e.g. Opn4
Both figures modified from: Schmidt et al. (2011)
Intrinsic Light ResponseEvaluation of response to
light
Traits include sensitivity based on both size of peak and duration
Modified from: Schmidt et al (2011)
Role in VisionRods and Cones = IF
Vision
ipRGCs = NIF Vision
Adapted from: http://www.photobiology.info/Sengupta.html
What Has Been DoneMethods:•Chemical reactions based on hypothesized pathway
Example:
•Conversion of chemical reactions to differential equations using mass action (and Michaelis-Menten kinetics)
Example:
•System of differential equations was solved in Matlab and the solution for the concentration of open channels was plotted
•Parameters (rate constants) were adjusted to fit experimental data with the help of MATLAB function fminunc.
What Has Been DoneResults: Note: Response of M1 cells
afff Electrophysiological data obtained from Jess and Abby Electrophysiological data obtained from R.L. Brown
What We’re Doing
Further DirectionsComplete literature review of non-M1 ipRGCs
Compile differences among different ipRGC classes
Incorporate those differences into the model
ReferencesReferences:Schmidt. "Melanopsin-Positive Intrinsically Photosensitive Retinal Ganglion Cells: From Form to Function." The Journal of Neuroscience, 9 Nov. 2011. Web. 20 Oct. 2014.Wong. "Photoresponse Diversity among the Five Types of Intrinsically Photosensitive Retinal Ganglion Cells." The Journal of Physiology, 3 Feb. 2014. Web. 20 Oct. 2014.Hattar et al. "Melanopsin-Expressing Retinal Ganglion-Cell Photoreceptors: Cellular Diversity and Role in Pattern Vision." Neuron (2010): 49-60. Print.
AcknowledgementsWe would like to thank:
UBM @ UMBCDrs. Phyllis Robinson Kathleen Hoffman, and Hye-Won KangAbigail Jackson and Jessica OrtegaPrevious CohortsThe Robinson Lab and its collaboratorsNSF
Recommended