Influence of temperature on retinal ganglion cell response and E.R.G. of goldfish

1. Extracellular recordings were made from the colour and spatial coded ganglion cells in the isolated goldfish retina.2. Electroretinograms (e.r.g.s) were obtained from unanaesthetized goldfish.3. For both types of responses the amplitude and phase characteristics were determined at various temperatures by means of Gaussian noise modulated light.4. The shape of these characteristics, depicted as Bode plots, is invariant with temperature. For the ganglion cell responses this holds from 7 to 19 degrees C, whereas for the e.r.g.s invariance is found over the entire range of temperatures used (6-30 degrees C).5. To obtain overlapping Bode plots shifts along the frequency axis are needed that are in accordance with the Arrhenius relation. The Q(10) of the e.r.g. is about 1.9 and of the spike response about 2.7.6. These relatively low values of Q(10) indicate that the dynamics of retinal signal transformations are dominated by diffusion controlled reactions. This implies that real transport delays can be neglected in retinal input-output relations.7. To verify whether a relationship exists between temperature and spectral coding, as has been suggested on the basis of behavioural studies, photopic e.r.g. action spectra were recorded and the spectral coding of ganglion cells were determined as a function of temperature.8. The results point to a temperature invariance of both the photopic e.r.g. action spectra and the colour coding of ganglion cell responses.9. The general conclusion of this study is that ;rules' found in the poikilothermic goldfish are not bound by temperature.