Dissociation of field potential from neuronal activity in the isolated retina: failure of the b-wave with normal ganglion cell response.

The b-wave of the isolated rabbit retina was compared with the ganglion cell response to light before and after modification of the retina's incubating medium. Marked diminution of the b-wave, with no reduction in ganglion cell response, was observed under three experimental conditions: (1) following a short period of anoxia; (2) following a short period in 0.2 mM Ca++; (3) in a small percentage of preparations, simply as a result of prolonged incubation in control medium. In contrast, a short period in 50 mM K+ led to a parallel fall and parallel recovery of both responses. It is apparent that under selected conditions the field potentials which constitute the b-wave are poorly correlated with the retina's neural activity.