Cocaine's effects on speech sound identification and reaction times in baboons

Abstract

The effects of cocaine on speech sound discriminations was examined to determine whether cocaine's previously demonstrated effect in reducing speech sound discriminability was dependent upon either the type of stimuli employed (simple tones versus complex speech) or the procedure (stimulus detection versus stimulus discrimination). Because of demonstrated similarities in the way that baboons and humans discriminate speech, and in the way the CNS is thought to encode and process speech sounds in these two species, baboons were trained to perform a choice procedure to identify the occurrence of different synthetic vowel sounds (see text). Animals held down a lever and released the lever only when one of four target vowels sounded, and not when a fifth, standard vowel sounded. Acute IM administration of cocaine (0.0032-1.0 mg/kg) produced dose-dependent decreases in vowel discriminability that were mostly due to elevations in false alarms (i.e., releases to the standard vowel) following cocaine. Cocaine also shortened reaction times to the stimuli in two of three baboons, but to a much lesser extent than observed previously. These results suggest that cocaine may interfere with the ability of the CNS to process the acoustic cues in speech sounds, and that the effects of cocaine on reaction times may depend upon the complexity of the reaction time procedure employed.

Design of Novel Assessment Techniques for Opioid Dependent Patients

“…Also, most commercial pupillometers assume that the outline of the pupil is circular, providing only an estimate of the pupil diameter. On the contrary, the pupil is noncircular with While no studies have reported using slurring in speech or reaction to a stimulus as an assessment tool prior to dosing, cocaine's effects on speech sound identification and reaction times in baboons have been studied [15]. Baboons were trained to release a lever on a particular vowel sound to test speech identification.…”