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. Author manuscript; available in PMC: 2008 Dec 1.
Published in final edited form as: Invest Ophthalmol Vis Sci. 2007 Dec;48(12):5788–5797. doi: 10.1167/iovs.07-0881

Figure 1.

Figure 1

Extraction of the electroretinographic oscillatory potentials (OPs). (A) An intact ERG elicited from a P20 control rat by a flash producing ~8500 photoisomerizations of rhodopsin per rod (R*). Fitted to the leading edge of the a-wave is a mathematical model of the activation of phototransduction, P3 (dashed line).35–37 P3 is digitally subtracted from the trace to produce the putatively pure postreceptoral P2. The OPs are demonstrated by passing P2 through a second-order Butterworth filter with band-pass of 60 to 235 Hz. The amplitude of the OPs (numbered) is measured to the peak of the OP wavelet from the trough immediately preceding it. The implicit time of each OP is measured from stimulus onset to the peak. (B) The OPs are transformed into the frequency domain by DFT of the filtered record. A Gaussian (equation 2) is fitted to the power spectrum (dashed line).