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1 December 2008 The conditioning and memory retention of planaria (Dugesia tigrina) for directional preferences
Sara M. Abbott, Gene K. Wong
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Planaria (Dugesia tigrina) are freshwater flatworms that are frequently studied because of their simple well-defined nervous system. Previous studies concluded that planaria can be trained to favor a direction in a Y- or T-maze using shock or other negative stimuli, but many of these experiments performed few overall runs and/or tested few individuals. The current study examines whether planaria have a directional bias and the ability to learn by using Y-mazes. The pre-conditioning period determined initial directional bias and was used to assign training directions. The conditioning period used electrical shock as a negative stimulus to condition planaria to select a specific turning direction in the Y-maze. Post-conditioning tested whether planaria maintained their learned behavior. Control planaria were not shocked during the conditioning period. Each period consisted of 3 trials with 10 runs in each trial. When examining the results of a single trial, many planaria demonstrated a directional bias. However, if individual trials for each experimental period were examined together, the majority of planaria were non-bias. Experimental planaria showed changes in their directional preferences during the conditioning period, but returned to their original bias, matching the controls, in post-conditioning. Planaria showed evidence of being trainable, but a total of 30 runs over 3 days may not be enough time for retention to occur.

Sara M. Abbott and Gene K. Wong "The conditioning and memory retention of planaria (Dugesia tigrina) for directional preferences," BIOS 79(4), 160-170, (1 December 2008).
Received: 19 July 2007; Accepted: 1 January 2008; Published: 1 December 2008

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