|
Abstract:
|
Receptive fields of retinal ganglion cells in turtle have excitatory and inhibitory components that are balanced
along the dimensions of wavelength, functional ON and OFF responses, and spatial assignments of center and
surround. These components were analyzed by spectral light adaptations and by the glutamate agonist,
2-amino-4-phosphonobutyric acid (APB). Extracellular recordings to stationary and moving spots of light were used
to map changes in receptive fields. ON spike counts minus OFF spike counts, derived from flashed stationary light
spots, quantified functional shifts by calculating normalized mean response modulations. The data show that
receptive fields are not static, but rather are dynamic arrangements which depend on linked, antagonistic balances
among the three dimensions of wavelength, ON and OFF response functions, and center0surround areas. |