Normal electrophysiology in retinas with reactive p27L-/L- Müller glia. Electroretinographic analysis was performed in experimental p27L-/L- and control mice during the peak of GFAP upregulation and during chronic GFAP expression (6 and 16 weeks post-inactivation). During these time periods the Müller glia nuclei migrated from their normal position (mid-inner retinal layers) toward the photoreceptor layer. Four to five mice were analyzed for each condition. (A and B) Representative scotopic and photopic electroretinogram (ERG) responses evoked by 10 decibel (dB) light flashes were recorded after dark adaptation and light adaptation, respectively. The fast components of the a- and b-waves reflect the functional integrity of photoreceptor and bipolar cell signaling, respectively. The slow components of the b-wave reflect Müller glial conductance. (C and D) Wave amplitudes were averaged from 4-5 mice per condition and shown as function of stimulating light intensity. Data are expressed as the mean ± SD.