Circadian rhythms of omitted stimulus potentials in the crayfish brain

Abstract

The omitted stimulus potential (OSP) is a type of event-related potentials elicited by cognitively-relevant stimuli associated with mental processes in humans. Crayfish also emit OSP when an expected stimulus does not arrive, although this is not considered to index a high-level cognitive event, but it is endogenous in nature because this depends on the recent history and arousal state of the animal. Although OSP is highly conserved in evolution, it had not been the subject of circadian study. Our hypothesis is that OSP, recorded in crayfish brain (Procambarus clarkii) has a circadian behaviour in its firing pattern. OSPs show circadian rhythms in both the latency and in the OSP/Sp ratio, under free-running (light:light, LL) and photoperiod (light:dark, LD) conditions, with main peaks during the daytime. This is the first report that shows a circadian pattern of OSP.

Keywords:

• Circadian rhythm
• crayfish
• brain
• omitted stimulus potentials