Higher-order habit strength and spatial learning

Abstract

This study examined the amount of acquisition trials necessary for higher-order habit formation to occur in the Morris water maze. After 8 days of acquisition, learning of the original platform location was predicted to be hippocampal-based, while after 16 days, learning was predicted to be a striatal-based higher-order habit. 16 male Long-Evans hooded rats were used. Rats were trained to find a platform in the water maze for either 8 or 16 days. Rats then experienced a 12-trial retraining session to a new platform location, followed by a probe test with quadrant preference measured. Both groups learned the platform locations at an equal rate. During the probe test, both groups showed a preference for the new location, indicating that learning of the original platform location may not have become habitual. Future research needs to extend the amount of acquisition training or determine a different paradigm for testing higher-order habit formation.