Extracellular potentials in the locust eye and optic lobe

Abstract

Extracellular potentials of two types were recorded from the locust eye and optic lobe; standing potentials relating to regions of the eye and optic lobe, and transient potential changes in response to light which alter the level of the former during adaptation. The transient changes are complex light and dark responses. The polarity and origin of the components are discussed. To brief exposures the light response in the photoreceptor region was found to continue in the subsequent dark period; dark responses therefore have a measurable latency in this region. A transient dark response (−ve) with no latency is recorded in the optic lobe. A point of unchanging potential was found at the basement membrane, and the asymmetrical potential changes on either side of this null-point are suggested as indicating possible dipole properties of the eye and optic lobe.