Classical conditioning in the fetal rat with a long delay between presentation of CS and US
✍ Scribed by Elena I. Varlinskaya; Evgeniy S. Petrov; Diane K. Simonik; William P. Smotherman
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 137 KB
- Volume
- 30
- Category
- Article
- ISSN
- 0012-1630
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✦ Synopsis
A single paired presentation of the artificial nipple and milk results in classical conditioning of changes in perioral responsiveness in the E20 rat fetus. This classical conditioning is evidenced by a reduction in responding to perioral tactile stimulation. The results of Experiment 1 confirmed the specificity of milk as an unconditioned stimulus to support classical conditioning. Experiment 2 demonstrated that single-trial classical conditioning with the artificial nipple CS and milk US was possible with a delay of 30 s between nipple and milk presentations. Further, measurements of fetal motor behavior during the delay between CS and US presentations indicated that a single 15-s presentation of the artificial nipple increased movements of the mouth for 30 s after removal of the artificial nipple. Experiment 3 demonstrated that three exposures to the artificial nipple prolonged the expression of mouthing for up to 120 s and made possible single trial classical conditioning with a delay of 120 s between CS and US presentations. The capacity of the fetal CNS to maintain a "behavioral trace" for an ecologically important stimulus, such as the nipple, could have adaptive significance in the early development of motivated behavior.