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T B Moye

Publications and source records attributed to T B Moye.

7 recordsLinked to original sources
PubMed1992

Contextual control of conflicting associations in the developing rat.

Two experiments examined the effects of manipulations of contextual cues on the expression of conflicting associations in 18-, 26-, and 35-day-old rats. Subjects learned to GO RIGHT in a water-filled T-maze, then were trained to reverse this position habit (GO LEFT). When the competing responses were learned in the same visual context, all age groups displayed a recency effect on a subsequent test in extinction; they behaved in accordance with the last-learned GO LEFT habit. If the competing responses were learned in different visual contexts, and testing took place in the context of the first problem, 35-day-old subjects behaved in a manner consistent with the GO RIGHT context (reduced recency). However, similarly trained 18-day-old subjects showed no evidence of a reduced recency effect. Given that 18-day-old rats are sensitive to other context manipulations, the present results suggest that the ability to "disambiguate" conflicting associations by context may depend upon the maturation of a relatively late-developing configural learning system.

Animals↗
PubMed1990

The cholinergic agent physostigmine enhances short-term-memory-based performance in the developing rat.

There are age-related differences in the rat's short-term memory processes. Rats 24-25 days old are 90% correct when the delay interval separating the forced run and choice run of a trial is either 10 or 30 s, but they perform at chance when the delay interval is 60 s. In contrast, the choice performance of 30-day-old rats remains constant across all delay intervals. It is reported that the cholinergic agent physostigmine dramatically improved the short-term-memory-based performance of rats 24-25 days old such that they displayed no loss in choice accuracy even when the delay interval was 60 s. No such enhanced performance was seen in rats treated with neostigmine, a peripherally acting anticholinesterase. The results support the hypothesis that postnatal maturational differences in central cholinergic systems may contribute to age-related differences in short-term memory.

Age Factors↗
PubMed1988

Physostigmine accelerates the development of associative memory processes in the infant rat.

Previous research has shown that 15-day-old rats are quite poor at associating temporally separated events. However, by 17 days of age, this capability has improved substantially (Moye and Rudy 1987a). In the present study, the centrally active anticholinesterase physostigmine was found to enhance the ability of 15-day-olds to associate a tone conditioned stimulus (CS) with a shock unconditioned stimulus (US) when these events were separated by a 10-s trace interval. In effect, the drug produced trace conditioning performance similar to that observed in older animals. We suggest that performance in the trace conditioning task requires the development of associative memory processes that allow the young rat to retain a representation of a CS over time. Furthermore, the enhancement of trace conditioning by physostigmine indicates that central cholinergic maturation is an important factor in the expression of associative memory.

Acoustic Stimulation↗
PubMed1987

Ontogenesis of trace conditioning in young rats: dissociation of associative and memory processes.

Hooded rats from 15 to 30 days of age were trained with a Pavlovian trace fear conditioning procedure in order to study the development of their capacity to learn associations between events separated in time. For both the auditory and visual systems, the associative processes necessary to learn about temporally contiguous events emerged earlier during ontogenesis than the processes necessary to integrate events separated in time. Furthermore, the ability of the rats to integrate events separated by increasingly long intervals continued to improve as they got older. We suggest that the emergence of the capacity to integrate temporally separate events reflects the maturation of memory processes that retain representations of stimulus events over time, and that these processes continue to mature for a considerable period after the basic associative processes have become functional.

Acoustic Stimulation↗
PubMed1985

Ontogenesis of learning: VI. Learned and unlearned responses to visual stimulation in the infant hooded rat.

A Pavlovian fear conditioning procedure was used to examine the ontogeny of the hooded rats' learned responses to visual stimulation. The data suggests a dissociation in the emergence of the processes required to detect visual events and those necessary for learning an association between visual stimulation and shock. Pups did not condition to a visual conditioned stimulus (CS) paired with a shock unconditioned stimulus (US) until they were 17 days old, even though 15-day-olds were clearly able to detect the visual CS. Although 15-day-olds failed to condition to the visual CS, they conditioned successfully when an auditory CS was paired with shock. Thus, the 15-day-olds' failure to condition to the visual CS was not due to a performance deficit or to a general ineffectiveness of shock as an US. These data suggest that the components of the visual system that mediate detection and those required for associative learning mature sequentially.

Age Factors↗
PubMed1984

Opiate and non-opiate analgesia induced by inescapable tail-shock: effects of dorsolateral funiculus lesions and decerebration.

Previous studies have demonstrated that inescapable tail-shock can produce either non-opiate or opiate short-term analgesia, dependent on the number of shocks delivered. Additionally, extended exposure to inescapable tail shock can produce long-term, opiate analgesic effects. Several lines of investigation suggest that the psychological dimension of perceived controllability may powerfully influence these phenomena in that each form of opiate analgesia can only be produced following exposure to inescapable, rather than equal amounts and distribution of escapable, shock. This has suggested that these opiate analgesias result from the organism's learning that it has no control over shock. Although it has been assumed that the opiate and non-opiate analgesias induced by tail shock may be subserved by neural circuitry similar to that mediating morphine analgesia and other forms of environmentally induced analgesia, no direct evidence exists to support this assumption. The present study sought to provide an initial attempt at defining the neural circuitry involved in these phenomena by examining the effect of bilateral dorsolateral funiculus (DLF) lesions and decerebration. These experiments revealed that pathways within the spinal cord DLF are critical for the production of short-term non-opiate analgesia, short-term opiate analgesia, and long-term opiate analgesia since bilateral DLF lesions abolished all three pain inhibitory effects. Additionally, it was found that decerebration did not attenuate either the short-term non-opiate or short-term opiate analgesia induced by inescapable tail shock. Combining the observations that these non-opiate and opiate short-term effects are not reduced by decerebration yet are abolished by DLF lesions clearly delimits the source of descending pain inhibition as being within the caudal brainstem.

Animals↗