1 Olfactory Conditioning Apparatus for Fruit Flies March 7, 2009 Team: Robert Bjerregaard-Team Leader Graham Bousley- Communicator Scott Carpenter- BWIG Chuck Donaldson- BSAC Client: Jerry Yin, Ph.D. Professor of Genetics and Psychiatry Advisor: Paul Thompson, Ph.D.2 Abstract Current devices that utilize fruit flies for research for the memory genes are largely similar, both in their functionality and restrictions. These devices share the trait that air flow and air pressure are uncontrolled variables in the experiments done on the subjects. While the experiment produces data to interpret, the data retrieved might not necessarily be as accurate. The client has previously attempted to resolve the problem without much luck. This is the first time that the client has employed engineers for anything more than advice. The goal for this semester is to modify the current design or design a completely new apparatus that has control over the environment in which the fruit flies are trained without compromising data integrity.3 Abstract……………………………………….…………………………………………………….………….………....2 Problem Statement……………………………………………………………………….……….……….………...4 Background.....................................................................................................................4 Motivation...........................................................................................................4 Design Constraints...............................................................................................5 Current Apparatus...........................................................................................................5 Current Procedure……………………………………………………………………………………………….…….6 Design Ideas....................................................................................................................7 1. Improving current design....................................................................................7 2. Solid Lexan Block.................................................................................................9 3. Cylindrical Selector………………………………………………………………………………………..10 Design Matrix..................................................................................................................12 Future Work....................................................................................................................14 References......................................................................................................................15 Product Design Specifications.........................................................................................164 Problem Statement Our goal is to create an apparatus that trains and tests fruit flies’ memory and ability to learn by means of electric shock and Pavlovian response. The apparatus must be able to control the pressure in the training and testing chambers, deliver a constant voltage across the flies in the training tube and have all elements encase the fruit flies in 5/8 inch diameter tubes. Background Motivation Dr. Jerry Yin conducts research on the memory genes for the University of Wisconsin – Madison. Research on the subject has been going on since the 1970’s, when the memory genes were identified. He and his colleagues came up with a design for an apparatus that would train fruit flies with odors, pairing one of the two with an electric shock and testing their ability to recall what they learned after the training was over. Those who designed this apparatus neglected to take into consideration effects of pressure and an electric grid that would deliver a consistent electric shock to the flies. While general information is know about fruit flies, nothing specific to their responses to changes in pressure and air flow are formulated. These factors showed up in the experimentation for memory. The researcher did some experiments5 related to pressure changes and airflow and realized it was a factor left unchecked. Were these problems fixed it would potentially increase accuracy of retrieved data and make that data much more meaningful. Design Constraints The following requirements must be included in the design process: 1. The apparatus must be able to control and monitor air pressure during the experiment. 2. It must be able to deliver a known voltage across an electric grid consistently. 3. It must be able to be cleaned and maintained effectively with low risk of damaging the apparatus to ensure long life span. 4. It must achieve data of similar or better accuracy than the previous device. 5. Diameter of testing and training tubes must be 5/8 inch or less. Current Apparatus The apparatus that is currently being used to test fruit flies’ learning ability and memory consists of three separate tubes connected to the main Lexan body (Figure 1). The top plastic tube, called the training tube, contains an electric grid used to shock the fruit flies. This electric grid delivers a shock of 70 volts across each fly. The bottom two tubes are considered the testing site, with the choice point in the Figure 1: Current Apparatus6 middle. Flies are transported from the training tube to the testing site via an elevator, which is part of the body. Odors are introduced through tubes connected to the ends of the three tubes. The odors are bubbled through mineral oil prior to being introduced to the tubes in order to humidify the air. This increases the flies’ ability to smell the odors. Airflow is powered by a pump that sucks air out of the middle of the Lexan body, so during training it is sucked out of the end of the tube, and during testing it is sucked out through the choice point. Current Procedure Training Training the fruit flies is a five step process. Approximately 100 flies are placed inside the training tube. First, air from the lab is passed by the flies for 45 seconds. Next, one odor is passed by the flies for one minute, and during this time the flies receive a shock of 70 volts every five seconds. The flies are then presented with air from the lab for 45 seconds. The second odor is then passed by the flies for one minute,
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