Biomaterial Database

Nature of the maintained discharge of Q, X, and Y retinal ganglion cells of the cat. 1987

J G Robson, and J B Troy

Physiological Laboratory, University of Cambridge, UK.

Cat retinal ganglion cells with center-surround receptive fields have an irregular discharge whose rate is altered by visual stimulation. In assessing the detectability of stimulus-induced changes in the discharge, a consideration of the power spectral density of the discharge is helpful. The power spectral density of Q, X, and Y cells is flat at low frequencies, rises to a peak at the mean frequency of firing, and then decays away at higher frequencies in an oscillatory manner to an asymptotic level equal to the mean rate of discharge. Measured spectra correspond closely with spectra predicted by a renewal-point process with gamma-distributed intervals. When the rate of the discharge is altered by visual stimulation, the spectral density at low frequencies remains roughly constant. Assuming that it is the noise power at these frequencies that is effective in limiting the detectability of visual stimuli, it appears that at the retinal level the irregularity of the discharge can be treated as an additive noise.

UI	MeSH Term	Description	Entries
D012160	Retina	The ten-layered nervous tissue membrane of the eye. It is continuous with the OPTIC NERVE and receives images of external objects and transmits visual impulses to the brain. Its outer surface is in contact with the CHOROID and the inner surface with the VITREOUS BODY. The outer-most layer is pigmented, whereas the inner nine layers are transparent.	Ora Serrata
D002415	Cats	The domestic cat, Felis catus, of the carnivore family FELIDAE, comprising over 30 different breeds. The domestic cat is descended primarily from the wild cat of Africa and extreme southwestern Asia. Though probably present in towns in Palestine as long ago as 7000 years, actual domestication occurred in Egypt about 4000 years ago. (From Walker's Mammals of the World, 6th ed, p801)	Felis catus,Felis domesticus,Domestic Cats,Felis domestica,Felis sylvestris catus,Cat,Cat, Domestic,Cats, Domestic,Domestic Cat
D004594	Electrophysiology	The study of the generation and behavior of electrical charges in living organisms particularly the nervous system and the effects of electricity on living organisms.
D000200	Action Potentials	Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.	Spike Potentials,Nerve Impulses,Action Potential,Impulse, Nerve,Impulses, Nerve,Nerve Impulse,Potential, Action,Potential, Spike,Potentials, Action,Potentials, Spike,Spike Potential
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D012165	Retinal Ganglion Cells	Neurons of the innermost layer of the retina, the internal plexiform layer. They are of variable sizes and shapes, and their axons project via the OPTIC NERVE to the brain. A small subset of these cells act as photoreceptors with projections to the SUPRACHIASMATIC NUCLEUS, the center for regulating CIRCADIAN RHYTHM.	Cell, Retinal Ganglion,Cells, Retinal Ganglion,Ganglion Cell, Retinal,Ganglion Cells, Retinal,Retinal Ganglion Cell
D013997	Time Factors	Elements of limited time intervals, contributing to particular results or situations.	Time Series,Factor, Time,Time Factor