Cephalopod skin patterns as windows into brain dynamics

Coleoid cephalopods (octopus, cuttlefish and squid) possess a unique skin display system that operates under direct neural control. This allows them to very rapidly change their body color, pattern and texture. They use this system for many functions, most prominently for camouflage. In camouflaging, a cephalopod extracts a statistical summary of the visual environment, and then adopts a matching skin pattern so as to escape detection from predators. Modern experimental and computational tools now make it possible to study this complex process in detail. I will describe our recent work revealing the space of camouflage patterns and dynamics of pattern matching. While sleeping, cephalopods paradoxically show rapid skin pattern changes. We performed behavioral manipulations and neural measurements showing that this is a distinct stage of sleep, strikingly similar to vertebrate REM sleep in its wake-like properties. These include the reactivation of waking skin patterns during sleep, suggestive of functions involving motor control and/or memory consolidation.