Dynamics of L-type bipolar and phasic amacrine cells in the vertebrate cone retina.
The model of the cone-L-HC circuit of the catfish retina (Siminoff 1985a) is extended to Luminosity bipolar cells (BC) and non-linear phasic amacrine cells (AC), but now applicable to the generalized vertebrate cone retina that involves only one cone type. Two types of BC's are simulated by linear transformation of 2 antagonistic inputs of differing time courses; the faster center field hyperpolarization from the cone and the slower surround field depolarization from the L-HC. The phasic AC was made non-linear by various methods: full- or half-wave rectification using either both or only one of the BC's as the inputs with rectification first and then summation or summation first and then rectification. A method is described using Laplace transforms in conjunction with the convolution theorem to obtain the impulse responses of BC's and AC's, in spite of the non-linearities of the AC even when used as feedback to the BC's. Since the input to the BC consists of 2 antagonistic inputs, feedback from the AC reinforces one input and attenuates the other.
D000818:Animals; D055592:Biophysical Phenomena; D001703:Biophysics; D004594:Electrophysiology; D005246:Feedback; D008959:Models, Neurological; D009474:Neurons / Q000502:physiology; D010786:Photoreceptor Cells / Q000502:physiology; D012160:Retina / Q000166:cytology / Q000502:physiology*; D014714:Vertebrates; D014785:Vision, Ocular / Q000502:physiology*