Vision Research Center


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Vision Science Seminar


UPenn - Vision Research Center Imaging and Electrophysiology Example Projects


December 2013: Two Photon Imaging of Zebra Fish Larva Lens Blood Vessels

3D animation


Recorded July 2012, Updated December 2013: Two Photon Imaging of Bipolar Cells in Flat-mounted Mouse Retina Expressing eGFP under mGluR6 Promoter

Z-stack animation (top view)


3D animation of the same region rotated -90° around X-axis

OPL (dendrites)


Cell bodies








IPL (axon terminals)



Imaged volume: 70x70x100 mm (XYZ)
Lens: Olympus LUMPIanFI/IR 60x/0.90W
Excitation wavelength: 910 nm


Two-photon imaging of Ca-responses in a mouse rod bipolar cell transfected with Ca-sensor GCaMP3

Before stimulation

After stimulation

Time-series animation

910 nm excitation, bright rectangular areas on time series correspond to light stimulation events.


December 2013: Confocal Imaging

Confocal image of GFP expressing retinal ON bipolar cells (lower image) that have been stained for G-gamma-13 (tope left) or the mGluR6 receptor (top right).



May 2013: Multi Electrode Array Recording from Mouse Retina

From top to bottom: time course of light stimulation, examples of raw data from 2 out of 60 MEA channels, raster plot and firing rate calculated after sorting of the raw data



June 2012: Mouse Cone and Rod Responses from Suction Pipette Recording

Left column: normalized response families of M-dominant mouse cone and a rod to a series of 5 ms 500 nm flashes. Middle column: Lamb and Pugh amplification analysis. Subsets of responses from the left panel are shown on the faster time scale together with theoretical traces (light gray) generated for amplification constants A indicated on the graph. Also shown dim-flash response time to peak measurements (Tpeak). Right panel: analysis to extract light sensitivity (1/ Qe) and dominant time constant of response recovery (τs).


June 2012: OCT Imaging in Canine

OTC in dogs

The VRC provides support for OCT imaging in canine. One example of the use of this instrument is in providing in vivo evidence of gene augmentation therapy success in XLPRA dogs. (A) Cross-sectional OCT retinal scans crossing the treatment bleb boundary (dashed line in H484, H483, and Z412) or comparing inside and outside the bleb region (white space in Z414) in treated eyes of XLPRA1 (H484, H483) and XLPRA2 (Z412, Z414) dogs. ONL is highlighted in blue for visibility. (Insets) Red line represents the location of the scans. In the treated (Tx) regions, there is better preservation of the photoreceptors and their nuclei. (B) The OCT scans over large retinal regions were used to generate topography maps of ONL thickness in treated eyes shown on a pseudocolor scale with superimposed retinal blood vessels and optic nerve. White represents no data; irregularly shaped black foci indicate retinotomy sites. Bleb boundaries are outlined with green-and-white dashed lines. Small inset figures are saline-treated control fellow eyes.

For details, refer to:
Beltran, W.A., Cideciyan, A.V., Lewin, A.S., Iwabe, S., Khanna, H., Sumaroka, A., Chiodo, V.A. Fajardo, D.S., Román, A.J., Deng, W.-T., Swider, M., Alemán, T.S., Boye, S.L., Genini, S., Swaroop, A., Hauswirth, W.W., Jacobson, S.G., Aguirre, G.D. Gene therapy rescues photoreceptor blindness in dogs and paves the way for treating human X-linked retinitis pigmentosa. Proc. Natl. Acad. Sci. USA 109(6): 2132-2137, 2012. (PMC3277562)


January 2012: Multi-Electrode Array Recording from Guinea Pig Retina

Multi Electrode Array GP

Dr. Balasubramian's lab has used the multi-electrode array to record from and characterize ganglion cell responses in guinea pig retina, with support from the Imaging and Electrophysiology module. The left panel of the image shows the electrode array. The blue traces in the upper right panel shows activity recorded from individual electrodes in the array in response to visual stimulation. Spikes are evident in some traces. The lower right panel shows the receptive fields of a number of simultaneously recorded ganglion cells. We are currently developing techniques to record from mouse retina. Contact Sergei Nikonov ( for information on using the MEA in your research.