Assessment of shock discrimination in rats with signal detection theory

Abstract

Nociception in six rats was evaluated with signal detection theory (TSD) techniques using a modified "yes-no" paradigm. A .l-sec•.075-mA shock was the discriminative stimulus for a choice to one side of a Tvmaze, and a .l-sec•.25-mA shock (capable of reliably eliciting a "flinch") was the discriminative stimulus for the opposite choice. Response bias was manipulated through differential reinforcement for the two choices. and signal sensitivity was manipulated by varying the intensity of the higher intensity shock signal. Individual detection ROCs appeared linear with slopes of one when plotted on double-probability scales. Indices of signal sensitivity and response bias were independent. as predicted by TSD. Morphine sulfate (4 mglkg) significantly reduced d' but did not affect (1, suggesting that. if appropriate parameters are used, TSD analyses may have value in assessing nociception in rats.

Effects of Morphine, Clonidine, and Intensity Change on Electric‐shock Discrimination

“…These results suggest that morphine's effects differ when monkeys are responding differentially in the presence and absence of shock from when they are responding differentially in the presence of two different shock intensities. Previous studies, using rats, have also reported differences between results with the two types of discrimination tasks (Grilly & Genovese, 1979;Grilly et al, 1980;Lloyd et al, 1978;Poling et al, 1978).…”

“…A preliminary report of this investigation appeared in Federation Proceedings (1982), 41 1978; Poling, Simmons, & Appel, 1978). Morphine also decreases correct responding in rats trained to respond differentially following the presentation of two different shock intensities (Grilly & Genovese, 1979). In contrast, diazepam and chlorpromazine have different effects in these situations.…”

Acute morphine dependence: Effects observed in shock and light discrimination tasks

“…As was discussed in our earlier report, the shock discrimination task involves signal-detection in which the rat must decide which of two events ("noise", i.e., the low shock, or "signal", i.e., the high shock) has occurred and respond accordingly. However, as we and others have argued, there are several potential effects of analgesic and hyperalgesic treatments if the noise is not "true" noise, so that the distributions of neural activity to both the noise and the signal may shift in their presence (Grilly and Genovese 1979;Grilly 1981;Grilly et al 1981;Rollman 1977). The relative degree of the shifts would depend on the magnitude and type of analgesic or hyperalgesic treatment (e.g., whether it differentially affects weak pain and intense pain), the actual intensities of the noise and signal, the number of exposures to altered noise and signal conditions, etc.…”

“…The results of the present study, using a similar procedure in a two-lever operant task, are in accord with these findings. The dose of morphine used in these studies was approximately 10-15 times higher than acute doses considered minimally analgesic in the rat (Fennessy and Lee 1975;Taber 1974) and behaviorally disruptive in this type of task (Grilly and Genovese 1979;Grilly et al /980). Our previous study ) also indicated that similar alterations in shock perception occur 2 days after chronic exposure to smaller doses of morphine.…”

“…Grilly of other studies using the shock discrimination paradigm, indicating that the direct behavioral effects of narcotics in shock discrimination tasks may not be related to their analgesic properties. For example, while some studies have noted that narcotics induce greater disruptions on shock presence S D trials than on shock absence (or lower intensity shock) trials (Lloyd et al 1978;Poling et al 1978;Dykstra 1979Dykstra , 1980, others have not observed differential effects (Grilly and Genovese 1979;Appel 1979, 1980;Grilly et al 1980;Grilly 1981 ;Genovese and Dykstra 1984). Furthermore, narcotics, in what are considered low to moderate analgesic doses for the respective species, have been shown to disrupt behavior in discrimination tasks involving non-noxious SD's (Hernandez and Appel 1979;Grilly et al 1980;West et al 1982;Koek and Slangen 1983 ;Nielson and Appel 1983).…”