New paradigms for tactile discrimination studies with the rat: methods for simple, conditional, and configural...

This paper describes a number of new tactile discrimination tasks for rats. Rats that were placed on a small platform were trained to pull up strings to obtain attached food pellets. When presented with two different sized strings, the rats acquired size discriminations and reversals within 5 to 10 days. When differences between string sizes were varied, the rats could discriminate differences less than one millimeter. A conditional task, in which the location of the correct string was made contingent on string size, was acquired within about forty days. A configural task, in which a compound of string size and odor predicted reinforcement, was acquired within about fifty days. The task is easy to use, provides good contiguity between specified cues and reinforcement, and can be easily modified to study a variety of within modality and cross modality sensory problems. Since the task can be adapted for simple associative, conditional, and configural problems it could prove useful for studying neurobiological substrates underlying learning and memory, cross modal matching, and recovery of function.