This abstract was presented today at the Association for Research in Vision and Opthalmology (ARVO) meetings in Seattle, Washington by Corinne N. Beier, Bryan W. Jones, Philip Huie, Yannis M. Paulus, Daniel Lavinsky, Loh-Shan B. Leung, Hiroyuki Nomoto, Robert E. Marc, Daniel V. Palanker, and Alexander Sher. Continue reading “Constructive Retinal Plasticity After Selective Ablation of the Photoreceptors”
Jason Shepherd, Assistant Professor in Neurobiology and Anatomy at the University of Utah will be delivering a seminar titled “Cellular Mechanisms of Experience Dependent Plasticity in Mouse Visual Cortex” on March 19th at 12:00 in the John A. Moran Eye Center Auditorium.
Abstract: A myriad of mechanisms have been suggested to account for the full richness of cortical plasticity. We found that visual cortex lacking the activity-dependent gene Arc is imprevious to the effects of deprivation or experience. Using intrinsic signal imaging and chronic visually evoked potential recordings, we found that Arc KO mice did not exhibit depression of deprived-eye responses or a shift in ocular dominance after brief monocular deprivation. Moreover, Arc KO mice lacked stimulus-selective response potentiation, as in in vivo form of plasticity that resembles long-term potentiation (LTP). Although Arc KO mice exhibited normal visual acuity, baseline ocular dominance was abnormal and resembled that observed after dark-rearing. These data suggest that Arc is required for the experience-dependent processes that normall establish and modify synaptic connections in visual cortex.
I’ve been doing some reading in plasticity recently and found this paper in the Journal of Neuroscience by Evan Vickers, Mean-Hwan Kim, Jozsef Vigh, and Henrique von Gersdorff published last summer that looks at short term plasticity in the Inner Plexiform Layer mediating light adaptation. Working in goldfish (Carassius auratus auratus) retina (an amazing retina), Vickers et. al. used patch clamp recordings on Mb bipolar cell terminals with paired-pulse light stimulation. The idea was to examine and quantify plasticity in GABAergic lateral IPSCs with findings that show variation in the synaptic strength and latencies which correspond to adaptation and sensitization to surround temporal contrast. The authors found that there are separate retinal circuitry pathways, each with differing mechanisms of plasticity that help to tune temporal response curves with glutamate release from ON bipolar cell terminals. They conclude that “Short-term plasticity of L-IPSCs may thus influence the strength, timing, and spatial extent of amacrine and ganglion cell inhibitory surrounds”.