Local pattern electroretinograms and ganglion cell activity in the turtle eye.

1. Local electroretinograms and spike activity from ganglion cells were recorded from an eye cup preparation of the turtle retina. The responses were elicited with striped and plaid stimulus patterns. 2. The results obtained with the two forms of recording were highly similar. Both depended on the spatial phase of the pattern with respect to the recording electrode. Both had maximal response at the same stimulus spatial frequency. 3. The optimum spatial frequency (both for maximum electroretinogram amplitudes and spike discharge rates) shifted to lower values with the administration of the GABA antagonist, picrotoxin. 4. The low frequency falloff associated with this spatial tuning may point to a mechanism of lateral interactions common to the local electroretinogram and spike responses.