Biomaterial Database

Model of the cone-horizontal cell circuit in the catfish retina. 1985

R Siminoff

A model of the cone-L-type horizontal cell circuit of the catfish contains 3 stages. The outer segment consists of a compression factor producing the Naka-Rushton relationship between amplitude of response and intensity and 7 low-pass filters in tandem that produces an absolute delay of about 15 ms. The cone pedicle consists of an internal negative feedback circuit in series with a low-pass filter. The L-type horizontal cell acts as a linear low-pass filter and forms the external negative feedback circuit with the cone pedicle. The system shows piecewise linearity with the feedback gain of the external negative feedback circuit directly proportional to the dc level of the horizontal cell. Thus, at any given mean illuminance the impulse response of the cone and L-HC adequately defines the dynamics of the responses. The conversion of a slow monophasic to a faster biphasic impulse response due to either an increase in mean illuminance or use of a steady annulus results from the change in the characteristic equation as the effective value of the feedback gain changes. By proper adjustment of gains and time constants, the cone-L-HC circuit of the catfish retina simulates the experimental data.

UI	MeSH Term	Description	Entries
D008959	Models, Neurological	Theoretical representations that simulate the behavior or activity of the neurological system, processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.	Neurologic Models,Model, Neurological,Neurologic Model,Neurological Model,Neurological Models,Model, Neurologic,Models, Neurologic
D010786	Photoreceptor Cells	Specialized cells that detect and transduce light. They are classified into two types based on their light reception structure, the ciliary photoreceptors and the rhabdomeric photoreceptors with MICROVILLI. Ciliary photoreceptor cells use OPSINS that activate a PHOSPHODIESTERASE phosphodiesterase cascade. Rhabdomeric photoreceptor cells use opsins that activate a PHOSPHOLIPASE C cascade.	Ciliary Photoreceptor Cells,Ciliary Photoreceptors,Rhabdomeric Photoreceptor Cells,Rhabdomeric Photoreceptors,Cell, Ciliary Photoreceptor,Cell, Photoreceptor,Cell, Rhabdomeric Photoreceptor,Cells, Ciliary Photoreceptor,Cells, Photoreceptor,Cells, Rhabdomeric Photoreceptor,Ciliary Photoreceptor,Ciliary Photoreceptor Cell,Photoreceptor Cell,Photoreceptor Cell, Ciliary,Photoreceptor Cell, Rhabdomeric,Photoreceptor Cells, Ciliary,Photoreceptor Cells, Rhabdomeric,Photoreceptor, Ciliary,Photoreceptor, Rhabdomeric,Photoreceptors, Ciliary,Photoreceptors, Rhabdomeric,Rhabdomeric Photoreceptor,Rhabdomeric Photoreceptor Cell
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.
D005399	Fishes	A group of cold-blooded, aquatic vertebrates having gills, fins, a cartilaginous or bony endoskeleton, and elongated bodies covered with scales.
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