One-trial conditioning of aerial respiratory behaviour in Lymnaea stagnalis.
Repeated spaced training sessions of contingent tactile stimulation to the pneumostome as it opens are required to cause long-term memory (LTM) formation of aerial respiratory behaviour making if difficult to determine exactly when memory forms. We have devised a single-trial aversive operant conditioning training procedure in Lymnaea to be better able to elucidate the causal mechanisms of LTM formation. Observations of baseline breathing behaviour in hypoxia were first made. Twenty-four hours later the snails were trained using the single trial procedure, by placing them in a small Petri dish containing 4 ml of 25 mM KCl for 30-35s as soon as the first pneumostome opening in hypoxia was attempted. LTM was present if (1) breathing behaviour following training was significantly less than before; and (2) breathing behaviour post-training was significantly less in experimental groups than in yoked control groups. LTM persisted for 24 h but not 48 h. Yoked controls that received an aversive stimulus not contingent with pneumostome opening had no evidence of memory. Cooling directly after, but not at any other time, blocks LTM formation. LTM formation was also prevented by removal of the cell body of the neuron RPeD1 before training.
Martens
Kara
K
Hotchkiss Brain Institute, University of Calgary, 3330 Hospital Dr NW, Calgary AB, Canada T2N 4N1.
Amarell
Martin
M
Parvez
Kashif
K
Hittel
Karla
K
De Caigny
Pascaline
P
Ito
Etsuro
E
Lukowiak
Ken
K
D000818:Animals; D003216:Conditioning, Operant; D008195:Lymnaea; D008568:Memory / Q000502:physiology; D012119:Respiration; D013312:Stress, Physiological / Q000503:physiopathology