title: Frequency Responses of Rat Retinal Ganglion Cells.
abstract: There are 15-20 different types of retinal ganglion cells (RGC) in the mammalian retina, each encoding different aspects of the visual scene. The mechanism by which post-synaptic signals from the retinal network generate spikes is determined by each cell's intrinsic electrical properties. Here we investigate the frequency responses of morphologically identified rat RGCs using intracellular injection of sinusoidal current waveforms, to assess their intrinsic capabilities with minimal contributions from the retinal network. Recorded cells were classified according to their morphological characteristics (A, B, C or D-type) and their stratification (inner (i), outer (o) or bistratified) in the inner plexiform layer (IPL). Most cell types had low- or band-pass frequency responses. A2, C1 and C4o cells were band-pass with peaks of 15-30 Hz and low-pass cutoffs above 56 Hz (A2 cells) and ~42 Hz (C1 and C4o cells). A1 and C2i/o cells were low-pass with peaks of 10-15 Hz (cutoffs 19-25 Hz). Bistratified D1 and D2 cells were also low-pass with peaks of 5-10 Hz (cutoffs ~16 Hz). The least responsive cells were the B2 and C3 types (peaks: 2-5 Hz, cutoffs: 8-11 Hz). We found no difference between cells stratifying in the inner and outer IPL (i.e., ON and OFF cells) or between cells with large and small somas or dendritic fields. Intrinsic physiological properties (input resistance, spike width and sag) had little impact on frequency response at low frequencies, but account for 30-40% of response variability at frequencies >30 Hz.
authors.affiliation: National Vision Research Institute, Australian College of Optometry, Carlton, Victoria, Australia.|ARC Centre of Excellence for Integrative Brain Function and Department of Optometry and Vision Sciences, University of Melbourne, Parkville, Victoria, Australia.
authors.forename: Alex E
authors.identifier: http://orcid.org/0000-0003-4055-5986
authors.initials: AE
authors.lastname: Hadjinicolaou
authors.affiliation: National Vision Research Institute, Australian College of Optometry, Carlton, Victoria, Australia.|ARC Centre of Excellence for Integrative Brain Function and Department of Optometry and Vision Sciences, University of Melbourne, Parkville, Victoria, Australia.|Department of Electrical and Electronic Engineering, University of Melbourne, Parkville, Victoria, Australia.
authors.forename: Shaun L
authors.initials: SL
authors.lastname: Cloherty
authors.affiliation: National Vision Research Institute, Australian College of Optometry, Carlton, Victoria, Australia.|ARC Centre of Excellence for Integrative Brain Function and Department of Optometry and Vision Sciences, University of Melbourne, Parkville, Victoria, Australia.
authors.forename: Yu-Shan
authors.initials: YS
authors.lastname: Hung
authors.affiliation: Department of Electrical and Electronic Engineering, University of Melbourne, Parkville, Victoria, Australia.
authors.forename: Tatiana
authors.initials: T
authors.lastname: Kameneva
authors.affiliation: National Vision Research Institute, Australian College of Optometry, Carlton, Victoria, Australia.|ARC Centre of Excellence for Integrative Brain Function and Department of Optometry and Vision Sciences, University of Melbourne, Parkville, Victoria, Australia.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Ibbotson
mesh_terms: D000818:Animals; D003712:Dendrites / Q000378:metabolism; D007150:Immunohistochemistry; D008564:Membrane Potentials; D018408:Patch-Clamp Techniques; D051381:Rats; D012165:Retinal Ganglion Cells / Q000502:physiology*; D055366:Synaptic Potentials