2009 Society for Neuroscience Meeting

Chicago, IL
Poster Abstracts:

The effects of scopolamine on rat serial pattern learning with water reward.  PDF

A.M. Chenoweth and S.B. Fountain, Department of Psychology, Kent State University, Kent, OH 44242.

Rats are sensitive to the structural organization of patterned sequences of responses (i.e., of "serial patterns"). For example, during acquisition rats make more errors at places where the structure changes, namely, on the first elements of chunks, than on within-chunk elements. Rats also have difficulty learning to anticipate violation elements that violate the rules set forth in a structured serial pattern. Prior research in our lab using atropine, a muscarinic cholinergic antagonist, produced evidence for the role of central cholinergic systems in the acquisition of a serial pattern containing a violation element using brain stimulation reward (BSR). The present study examined the effects of scopolamine on acquisition of serial patterns using water reinforcement. Rats were given daily i.p. injections of scopolamine (0.6 mg/kg) 30 min prior to training in an octagonal operant chamber equipped with a nose poke receptacle on each wall. Rats learned to nose poke for water reinforcement in a particular order (the serial pattern) in a discrete-trial procedure with correction. The rats learned the pattern: 123 234 345 456 567 678 781 818, where the digits represent the clock-wise positions of receptacles in the chamber, spaces indicate 3-s pauses, other intertrial intervals were 1 s, and the last pattern element violated pattern structure. Rats received 10 patterns a day throughout acquisition. Central cholinergic blockade by scopolamine caused profound impairments in acquisition for chunk boundary elements (the first element of chunks) and the violation element of the pattern, but did not affect acquisition for within-chunk elements. Although other studies sometimes show different behavioral effects of scopolamine with water reinforcement versus other reinforcers, our results with water reinforcement paralleled those observed earlier with BSR. The results reinforce our earlier claims that intact central cholinergic systems are necessary for learning appropriate responses at places in sequences where pattern structure changes. Further, the differential impairment of element types suggests that multiple neural processes are likely involved in sequential learning.


Animal Cognition & Neuroscience

Department of Psychological Sciences Kent State University Kent, OH 44242