PRIMITIVE NERVOUS SYSTEMS. CONTROL AND RECOVERY OF FEEDING BEHAVIOR IN THE POLYCLAD FLATWORM, NOTOPLANA ACTICOLA

Abstract

Feeding behavior in N. acticola involves a series of local responses which are under central control. Behavior involves recognizing food, gripping with the tail and turning towards the prey. Food is then conveyed to the mid-ventral mouth and swallowed. Worms are able to ingest food in the absence of the brain using local reflexes. Central control is abolished in areas posterior to cuts through the body wall. Functional recovery of behavior occurs in a minimum of 8 h following closure of a wound. Anatomical fusion of severed nerves occurs and conduction of action potentials across the healed region can be demonstrated. Recovery of function also occurs in approximately 36-48 h if the cut is not allowed to heal, suggesting that new or normally unused pathways can be recruited.