Pre Exposure Stimulus Intensity And The Latent Inhibition Effect

Author : Laura Vroman
Publisher :
ISBN 13 :
Total Pages : 70 pages
Book Rating : 4.:/5 (712 download)

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Download or read book Parameters that Affect the Expression of Conditioned Stimulus Pre-exposure/latent Inhibition in Honey Bees, Aps Mellifera written by Laura Vroman and published by . This book was released on 2006 with total page 70 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Learning is important to honey bees in their natural environment. Foraging worker honey bees must be able to learn the association of cues with floral nectar and pollen rewards. They must also be able to learn which flowers are non-rewarding through frequent visits to that flower. Choice behavior for resources probably involves the learning mechanism conditioned stimulus pre-exposure (CSPE), also known as latent inhibition. CSPE effect is expressed when a stimulus is presented without reinforcement, and subsequently the same test subject shows a decreased speed of learning when this same stimulus is paired with reinforcement. Experiments were preformed on the honey bee, Apis mellifera L. to address these three questions: does repetition of the pre-exposed CS have an affect on the expression of CSPE; does the stimulus used during conditioning have an affect on the expression of CSPE; is CSPE expression affected by CS concentration/intensity. Exiting foragers were collected from the entrance of the colony, harnessed, and fed. The following day, honey bees were tested and chosen based on their desire to feed using the proboscis extension response (PER) assay. Those honey bees that extended their proboscis were chosen. A pre-exposure training procedure and conditioning procedure took place to determine the parameters that affect CSPE. During the pre-exposure training, subjects were exposed to an odor at a varying number of times depending on the experiment. During the conditioning procedure a 'forward pairing' conditioning was used across six trials where sucrose was paired with a stimulus to elicit proboscis extension. A positive response was recorded if the subject extended its proboscis with presentation of odor alone. In the first experiment, the number of conditioned stimulus pre-exposures was examined. Subjects were placed in a station where they were pre-exposed to an odor stimulus without reinforcement 0, 1, 2, 4, 8, 10, 20, 25, 30, or 40 times and conditioned to that same preexposed odor and concentration. In next experiment, the conditioned stimulus was examined. Subjects were pre-exposed without reinforcement to 40 odor stimulations and conditioned to the pre-exposed odor and a novel odor at the same concentration used during pre-exposure training. In last experiment, the CS pre-exposure concentrationlintensity was examined. Subjects were pre-exposed without reinforcement to three concentrations of odor stimulus 40 times and conditioned to both the same odor used during pre-exposure training and a novel odor at all three odor concentrations. In all three experiments CSPE expression was examined at high (2.OM), intermediate (0.02M), and low (0.002M) odor stimulus concentration. CSPE effect was affected by: the number of CS pre-exposures, the stimulus used during conditioning, and CS intensity. I was able to produce CSPE effect after 10 preexposures to the CS stimulus at high concentration, which was lower than previous findings in other species. The pre-exposed odor used during conditioning caused either a larger CSPE effect or a decrease in response when compared to the novel odor. This would be expected because the subject had not been previously exposed to the novel odor. CSPE expression was a direct function of the pre-exposed stimulus intensity using the proboscis extension response in honey bees. I determined that foraging honey bees are not able to express the CSPE effect at low concentration as well as they can at high concentrations. Therefore honey bees in nature may have a hard time learning not to return to non-rewarding flowers that have a low odor concentration. Other cues may have to be used to identify non-rewarding flowers. Theories of CSPE effect are discussed.