Possible noradrenergic involvement in training stimulus intensity.
Day-old chicks trained on a single trial passive discrimination avoidance task using a concentrated chemical aversant, methyl anthranilate (MeA), have been shown to exhibit three stages of memory processing: short, intermediate and long term. A similar learning task with the aversant diluted to 20% in ethanol leads to short- and intermediate-term memory only, but not to long-term memory. The emergence of long-term memory has been shown to be associated with the production of a nonenergy-dependent phase of the intermediate memory stage. Subcutaneous administration of propranolol proved capable of inhibiting this nonenergy-dependent phase of memory under a number of training regimes: strongly reinforced training, and with weakly reinforced training presented twice or coupled with a selected dose of the stress-related hormone ACTH. This study supports the notion that there is a phase of memory that occurs prior to the protein synthesis-dependent phase of memory which is susceptible to interference by drugs affecting noradrenergic processes and which may be associated with the intensity of the training stimulus.
Crowe
S F
SF
Department of Psychology, Latrobe University, Bundoora, Victoria, Australia.
Ng
K T
KT
Gibbs
M E
ME
D000818:Animals; D001143:Arousal / Q000502:physiology; D001362:Avoidance Learning / Q000187:drug effects; D002645:Chickens; D004193:Discrimination Learning / Q000187:drug effects*; D009638:Norepinephrine / Q000502:physiology*; D011433:Propranolol / Q000494:pharmacology*; D012054:Reinforcement, Psychology; D013564:Sympathetic Nervous System / Q000502:physiology*; D015016:Yohimbine / Q000494:pharmacology; D062367:ortho-Aminobenzoates / Q000494:pharmacology
D062367:ortho-Aminobenzoates; D015016:Yohimbine; C038892:methyl anthranilate; D011433:Propranolol; D009638:Norepinephrine