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Dec 6, 2023





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Running head: OPERANT CONDITIONING AND SNIFFY 1 Operant Conditioning and Sniffy Hunter College, City University of New York
OPERANT CONDITIONING AND SNIFFY 2 Abstract The Sniffy Pro is a program that provides a simulated rat (Sniffy) in a computer- generated operant chamber to study learning and conditioning. This virtual rat simulated performance of brain stimulation rewarding through operant conditioning. Sniffy was trained to lever press for reinforcement. Data was used from live rates achievement of brain stimulation reward threshold. Researchers questioned the threshold value for baseline and food deprivation rates. Results showed threshold values for baseline was significantly higher than values for food deprivation. 24-hour food deprivation lowers brain stimulation reward thresholds. Keywords : Sniffy, operant conditioning, brain stimulation, reward system Operant Conditioning Operant conditioning is a method of learning established by B.F. Skinner. This learning process occurs through rewards and punishments. Shaping is used to evoke a response as
OPERANT CONDITIONING AND SNIFFY 3 subjects make associations between behavior and consequence. B.F. Skinner conducted numerous experiments on animals to support his theory on operant conditioning. Since then many psychologists have performed the same experiments using rats and a Skinner box to validate and advance B.F. Skinner’s theory of operant conditioning. The lateral hypothalamus is essential for regulating metabolism and food intake. Ghrelin receptors are stomach produced hormones that stimulate ingestion behavior and increases motivated behavior to obtain palatable foods ( López-Ferreras et al., 2017). This area is crucial to food intake as associated lesions advance into aphagia and anorexia. Contrary to this the ventromedial hypothalamus is the nucleus of the hypothalamus involved in terminating hunger, this area is in due to the feeling of fullness. Research has shown that lesions in the ventromedial hypothalamus lead to overconsumptions and obesity. Rats used in experiments became overconsumed by freely available food and were less responsive to control when food was obtained by lever pressing ( Hawkins, Inoue, Mori, & Torii, 1994). These studies lead to the strong notion that the brain utilizes mechanisms that deal with behaviors. Such behaviors, like food intake, are turned on and off depending on whether a need is present or reduced. The study of the mechanisms of hunger closely relates to that of positive emotions. It was discovered that rats would lever press at exceptionally high response rates for the reward of brief electrical pulses (Olds & Milner, 1954). Later it was found that the lateral hypothalamus would functions as rewards sites just as it would evoke feeding behavior (Margules & Olds, 1962). This was then further supported as it was showed satiety reduced brain stimulation reward responding and deprivation enhanced brain stimulation reward responding through rats bearing electrode cannulas for electrical brain stimulation (Hoebel & Teitelbaum, 1961).
OPERANT CONDITIONING AND SNIFFY 4 The research on reward mechanisms, food intake and hunger has led to many advancements in research and treatment in addiction and mental illness. This current experiment was conducted to further support the findings of how reward is mediated and the close relationship between the sites that control motivation. The researchers hypothesized that the virtual rat, sniffy, will learn to lever press for reinforcement through operant conditioning. The second hypothesis was 24-hour food deprivation lowers brain stimulation reward thresholds. Methods Subjects
OPERANT CONDITIONING AND SNIFFY 5 The experiment was performed using Operant Conditioning Training Demonstration : Sniffy the virtual rat. This was based on data from live Sprague-Dawley albino rats maintained on ad libitum food and water except for the food deprivation condition when only water was available. The animals were maintained under a 12:12 light dark schedule. The rats used in the brain stimulation reward experiments were surgically implanted with a single bipolar electrode aimed at the LH under IACUC approved surgical, anesthetic and post-operative procedures. Materials and Apparatus The virtual rat was held in an operant conditioning chamber, also known as a skinner box, that was just comfortably large enough to accommodate the rat being held inside of it. This chamber was sound proof and light proof to avoid distracting stimuli. On one wall there was a speaker to the right, a spherical object protruding from the wall to the left, and in the middle was a lever in which food was released from when pulled. Electrical brain stimulation equipment included pc computer, electrical constant current stimulator, oscilloscope, operant chamber from Coulbourn Instruments, and a printer. Threshold was determined using the Lewis and Phelps rate-independent brain stimulation computer program. Procedures The first experiment intended to train Sniffy to lever press through demonstration of operant conditioning. Each group of students in the class used the Sniffy Pro virtual rat program downloaded into the PC computers set up in the lab room. This program was used to experience standard operant training, Sniffy was magazine trained to the magazine mechanism that dispenses food reinforcement. This was done by clicking every time Sniffy got close to the mechanism in order to dispense food for her. Then she was trained to lever press for continuous
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