INFLUENCE OF 4 FIRST ANTERIOR GANGLIA ON LEARNED BEHAVIOR IN LUMBRICUS TERRESTRIS

A series of nineteen worms were trained in a T-maze using sandpaper and electric shocks as punishment at one arm and a dark burrow as reward at the other arm of maze. A turning habit towards the reward developed smoothly after about 200 trials. Electrical responses of homologous peripheral nerves during electric stimulations of cephalad connectives were recorded in worms that had already established the habit. No difference between both sides of a metameric segment was observed. The effect of a regenerated anterior part of nervous system (suprapharyngeal, subpharyngeal, fourth and fifth ganglia) and the effect of the isolation and reconnection of the mentioned structures on this learnt habit was studied. The former condition was attained by amputation and the latter by connective severance. Results show that in both cases the habit is lost at about the 40th post-operative day and for about 16 days. A common factor for the two referred conditions is discussed. © 1968.