Temporal determinants of olfactory long-term retention in honeybee classical conditioning: nonmonotonous effects of the training trial interval.
The question of which acquisition parameters govern long-term retention is important to an understanding of memory function. We investigate the effects of the time interval between learning trials on mediate (1 day)- and long-term (4 days) retention. In classical conditioning of the proboscis extension reflex, we train honeybees to associate an odorant with a sucrose reward using intertrial intervals of either 30 s, 1 min, 3 min, or 20 min. Intervals of 20 and 1 min result in stable retention but 3-min and 30-s intervals result in reduced retention after 4 days compared to that seen after 1 day. Thus, stability of long-term retention depends nonmonotonously on the intertrial interval. Reduced retention with 3-min intervals might be caused by a disruption of memory consolidation which is known to be especially sensitive to interference 3 min after a conditioning trial. Habituation and backward inhibitory learning are discussed as explanations for reduced retention with 30-s intervals.
Gerber
B
B
Insititut für Neurobiologie, Freie Universität Berlin, Berlin, Germany. gerber@zedat.fu-berlin.de
Wüstenberg
D
D
Schütz
A
A
Menzel
R
R
D000818:Animals; D001516:Bees / Q000502:physiology*; D003214:Conditioning, Classical; D007858:Learning; D012153:Retention, Psychology / Q000502:physiology*; D012903:Smell / Q000502:physiology*; D013997:Time Factors