Stimulus modality and short-term memory in rats

Abstract

Two experimental paradigms are presented aimed at determining the retention of auditory and visual information over brief delay intervals. First, a conditional delayed matching-tosample procedure was used in which rats were required to symbolically match the modality of the sample stimulus with one of two comparison stimuli. In the second experiment, subjects were trained and tested using a Konorski-type procedure. Despite the conceptual and procedural differences between the two procedures, subjects in both experiments showed steeper forgetting functions for visual events than for auditory events, while performance levels at O-sec delay intervals were equivalent for both stimuli. These results, when taken together with related research conducted with pigeons, suggest that content of memory may have important influenceson the short-term retention abilities of animal subjects.Surprisingly little is known about forgetting of recent events in the laboratory rat. Although Hunter (1913) reported that rats could retain the spatial location of visual stimulus representing food for a maximumof 10 sec, successful performance appeared to be dependent upon the use of response-directing behaviors which mediated the delay. More recent investigators have modified Hunter's procedure and have studied short-term retention using delayed response and delayed alternation tasks (e.g., Gordon, Brennan, & Schlesinger, 1976;Roberts, 1974). These paradigms have been problematic, however, primarily because they do not allow for precise experimental specification of the event the rat is required to retain. While the delayed matching-to-sample (DMTS) task has proven to be a useful method for measuring

The influence of stimulus attributes on duration matching-to-sample in pigeons

“…There is substantial evidence that stimulus characteristics can influence delayed MTS (Columbo & D' Amato, 1986;Kraemer & Roberts, 1984;Urcuioli & Zentall, 1986;Wallace et al, 1980), but our results showed that working memory was unaffected by stimulus properties that did influence duration estimation. This dissociation is especially relevant to the analoguecoding interpretation of duration MTS.…”

“…This question becomes particularly relevant for situations in which the target behavior involves both timing and memory, as is the case with duration matchingto-sample (MTS). Independent evidence indicates that signal properties influence duration estimation (Kraemer et al, 1995;Wilkie, 1987) and working memory (Columbo & D' Amato, 1986;Kraemer & Roberts, 1984;Wallace, Steinert, Scobie, & Spear, 1980), but what is not known is whether the same signal properties that influence duration estimation also influence working memory.…”

Effects of proactive interference on rats’ continuous nonmatching-to-sample performance

“…Analogous studies have produced similar results in go/no-go delayed-alternation tasks (Heise, Note 2). However, retention-interval duration should have little effect on responsivity in paired-trial tasks (e.g., Wallace et al, 1980). since the retention interval occupies a relatively small portion of the time between response opportunities.…”

“…However, in recent years there has been an increasing interest in using OMS tasks to study memory in other animal species (e.g., Herman & Gordon, 1974;Wallace, Steinert, Scobie, & Spear, 1980). This research has been motivated both by an interest in between-species comparisons and by a desire to capitalize on the unique advantages (e.g., genetic purity, evolutionary importance, suitability for physiological research) that particular species offer for the study of the biological basis of behavior.…”

“…This paper introduces a new form of the delayed matching-tosample paradigm, the continuous nonmatching-tosample (CNM) task, that can be used to study shortterm memory in rats. The CNM is a variant of the go/no-go matching-to-sample task introduced by Konorski (1959;Chorazyna, 1959) and recently used with rats by Wallace et al (1980;see also Bradley & Roberts, 1965;Stepien & Cordeau, 1960;Wasserman, 1976). In the CNM procedure, a variable number of trials with one stimulus alternates with a variable number of trials with a second stimulus.…”