Quantification of the Effects of Chlorpromazine on Performance Under Delayed Matching to Sample in Pigeons

Abstract

The effects of four doses of chlorpromazine (dose range 0.5 to 12.5 mg/kg) on performance under a delayed matching-to-sample procedure in pigeons was investigated, using the exponential model of memory (White, 1985). Performance was measured using a bias-free measure of discriminability, log d (Davison & Tustin, 1978), and negative exponential functions were fitted to individual-subject and group data at each dose level. A decrease in matching accuracy was found to be caused by an increase in the rate of forgetting, b, and a decrease in the initial discriminability, log d0. Changes in rate of forgetting and discriminability occurred at doses that had no statistically significant effect on response latency. The exponential model of memory accounted well for the data and provided a useful way of quantifying the effects of chlorpromazine on the processes involved in delayed matching-to-sample performance.

Effects of the NMDA antagonists CPP and MK-801 on delayed conditional discrimination

“…The lack of effect on rate of forgetting in the present situation does not rule out, therefore, changes in a form of memory with a much longer time constant than that estimated in the present analyses by the parameter b. The sparing of b by these drugs is in contrast to effects obtained by Watson and Blampied (1989) with chlorpromazine in delayed matching to sample with pigeons. They tested doses in the range 0.5-12.5 mg/kg and found impairments of both log d and b, with b showing an apparently greater sensitivity to the drug.…”

Forgetting functions

“…The result was a systematic reduction in the intercept parameter of fitted exponential functions without a change in the rate of forgetting (also see Kirk, White, & McNaughton, 1988). Other drugs, such as chlorpromazine (Watson & Blampied, 1989) and phenobarbital (White, Harper, & Watson, 1994), increase rate of forgetting and reduce initial discriminability. There seem to be no drugs that affect rate of forgetting without also influencing initial discriminability (White, Ruske, & Colombo, 1996).…”

Cognitive effects of psychotomimetic drugs in rats discriminating number cues

“…The accuracy of choice behavior was also analyzed using signal detection analysis (SD) methods similar to those used in other complex discriminations (Willmore et al 2002; Kirk et al 1988; Watson and Blampied 1989; Tan et al 1989; White et al 1989; Poorheidari et al 1998). For our SD measurements, response bias (log bias) and a bias-free measure of discriminability (log d , referred to as d ′ in the present paper) were calculated using the following equation: $$d^{\prime }=0.5log\left(\left[C_{\text{high}}\times C_{\text{low}}\right]÷\left[E_{\text{high}}\times E_{\text{low}}\right]\right)$$…”