A novel touch-sensitive apparatus for behavioral studies in unrestrained squirrel monkeys

Abstract

Despite the increasing sophistication and affordability of touch-sensitive technology, its use in the behavioral sciences has been limited. The present paper describes the design and empirical validation of a novel touch-sensitive operant conditioning chamber for use with unrestrained squirrel monkeys. In addition, results from a variant of a commonly employed animal model of learning, the repeated acquisition task, demonstrate the effectiveness of this chamber in programming an assay of complex behavior. Finally, results from a study with Δ(9)-tetrahydrocannabinol, the active ingredient in marijuana, show that its effects in this novel touchscreen chamber were consistent with its dose-related effects on learning using more conventional approaches. Overall, these studies indicate the touchscreen apparatus provides effective means for programming complex behavioral tasks to assess the effects of pharmacological agents on cognitive function.

Figure 1

Schematic and photograph of the experimental apparatus. See apparatus section 2.1.2 for measurement details.

Figure 1

Schematic and photograph of the experimental apparatus. See apparatus section 2.1.2 for measurement details.

Figure 2

Mean response rates (±SEM) across 9 areas of the screen under FR1, 3, 5, and 10.

Figure 3

The number of trials into the repeated acquisition session where the subject responded to the S⁺ stimulus on the previous 9 of 10 trials (i.e., our discrimination mastery criterion) across 30 successive sessions.

Figure 4

Effects of Δ⁹-THC on trial-by-trial acquisition performance. Cumulative correct trials are plotted as a function of cumulative total trials following administration of Δ⁹-THC for an individual squirrel monkey. The thickness of the data series is related to dose with thicker lines representing performance under larger doses of Δ⁹-THC. Dashed reference line represents 100% accuracy.

Figure 5

Upper panel: Effects of Δ⁹-THC and saline (S) on overall session accuracy (±SEM). Control (C) values represent the average accuracy of all sessions immediately prior to drug administration sessions. Accuracy values were set to 0% correct to represent sessions in which discrimination performance was abolished throughout the 2-hr session. Lower panel: Effects of Δ⁹-THC and saline (S) on latency to respond (±SEM). Control (C) values represent the average accuracy of all sessions immediately prior to drug administration sessions. Latency values were set to 7,200 s to represent sessions in which discrimination performance was abolished throughout the 2-hr session. Data transformed by dividing 1 by the latency for ease of comparison with the top panel.