OPERANT-CONDITIONING OF AERIAL RESPIRATORY BEHAVIOR IN LYMNAEA-STAGNALIS

In this study, we operantly conditioned the aerial respiratory behavio ur of the freshwater snail Lymnaea stagnalis., Aerial respiration in L ymnaea stagnalis is accomplished by the spontaneous opening and closin g of its respiratory orifice, the pneumostome, at the water surface. W eak tactile stimulation of the pneumostome area, when the pneumostome is open, evoked only the pneumostome closure response, which is one as pect of the escape-withdrawal reflex. Pneumostome stimulation resulted in its closure and the termination of aerial respiratory activity, A contingent tactile stimulation paradigm was used to operantly conditio n the animals, Stimulation of the pneumostome whenever the animal atte mpted to breathe resulted in significantly fewer attempts to open the pneumostome as training progressed, The latency of the first breath (s ubsequent to stimulation), the number of breaths and the total breathi ng time were measured before and after each training period, Significa nt, quantifiable changes in these behavioural parameters were observed only in the operant conditioning group animals, Control animals recei ving tactile stimulation to their pneumostome not contingent upon pneu mostome opening movements (yoked controls) or those that were physical ly prevented from surfacing to breathe (hypoxic controls), did not exh ibit significant changes in these behavioural parameters, Our data pro vide the first direct evidence for operant conditioning of respiration in any animal.