A new paradigm to analyze observational learning in rats

L. Mandolesi^1,3, M.G. Leggio^2,3, F. Federico^2,3 and L. Petrosini^2,3

¹Department of Studies of Institutions and Territorial Systems, University of Naples Parthenope, Italy
²Department of Psychology, University of Rome La Sapienza, Italy
³IRCCS Fondazione Santa Lucia, Rome, Italy

Neuroimaging studies demonstrated that observation of movements performed by others, imagination of actions and actual execution of motor performances share common neural substrates and that the cerebellum is among these shared areas. Experimental evidence demonstrated that cerebellar networks are involved in spatial learning, controlling in particular the acquisition of exploration strategies without blocking motor execution of the task. On such a basis, we developed a new paradigm of observational learning to analyze the effects of observation in learning a spatial task, focusing the cerebellar role in learning a spatial ability by observation. Observer animals were separately housed in small cages suspended over a water maze tank. They repeatedly observed companion actor rats performing spatial tasks differing according to the experimental requirements. After the observational training, observer animals were hemicerebellectomized to block further acquisition of new navigational strategies during actual performance of swimming task. When cerebellar symptomatology stabilized, observers were actually tested in the Morris Water Maze task they had previously observed. Observers displayed exploration abilities closely matching the previously observed behaviours, indicating that they did learn complex navigational strategies by observation. Interestingly, whether the cerebellar lesion preceded observation training, complete lack of spatial observational learning was observed. As already demonstrated for the acquisition of spatial procedures through actual execution, cerebellar circuits appear to play a key role in the acquisition of spatial procedures also through observation. Furthermore, the present protocol allowing to split a complex spatial behaviour into the single behavioral units forming the complete procedural sequence, demonstrated that such behavioral units do exist and can be independently acquired. Furthermore, this new paradigm has the potentials to answer the question whether the split behavioral units are really the most simple ones, or whether it is possible to continue breaking up a complex behavior into simpler and simpler components until the ‘quark’ of a complex behavior is reached.

Paper presented at Measuring Behavior 2005 , 5^th International Conference on Methods and Techniques in Behavioral Research, 30 August - 2 September 2005, Wageningen, The Netherlands.

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