Interactions between response stereotypy and memory strategies on the eight-arm radial maze

Abstract

!Three groups of water-deprived rats collected water from the ends of the 8 arms of an 8-arm radial maze. Sighted subjects, and subjects blinded either with or without pre-enucleation experience on the radial maze, all retrieved the water efficiently. Most of the subjects exhibited the same response stereotypy, regularly choosing 8 adjacent arms of the maze, then stopping in the center of the maze. The strategies underlying this performance were analyzed by interrupting trials and rotating the maze 180° after the subject had made 3 choices. Sighted subjects depended on extramaze stimuli, naive-blind subjects depended on intramaze stimuli and experienced-blind subjects ignored their initial 3 choices after the trial was interrupted. Choice accuracy was equally good whether the subject was returned to the position from which it had been removed, or returned to the opposite side of the central platform. All 3 groups of subjects maintained their stereotyped adjacent-arm responding only as long as such responding was consistent with high choice accuracy. Response stereotypy was prevalent on the radial maze, but response strategies were secondary to memory strategies.

The effects of maze-arm length on performance in the radial-arm maze

“…Thus, the bias to visit adjacent arms demonstrated by the ratsin the short-arm condition persisted even when it resulted in a substantial number of errors. This is quite different from the results of previously reported experiments in whichrats continued to exhibithigh levels of choice accuracy when stereotypic response patterns were disrupted (Dale& Innis, 1986;Olton et al, 1977).…”

“…In agreement witha numberof previous findings (e.g., Brown & Cook, 1986;Dale & Innis, 1986;Foreman, 1985;Olton et al, 1977), the rats in the present experimentexhibited somedegree of stereotypy in their choice behavior. The majority of choices made in both groups were to arms either adjacent to, or separated by a single arm from, the previous choice.…”

“…The majority of choices made in both groups were to arms either adjacent to, or separated by a single arm from, the previous choice. Previous experiments have shown that even rats exhibiting marked consistency in turning magnitude sometimes demonstrate high levelsof choice accuracy when procedures are introduced to prevent such biases (Dale & Innis, 1986;Olton et al, 1977 .. ing over blocks. Figure 4 shows the mean percentage of correct choices for the various conditions of the experiment.…”

Plant ecology meets animal cognition: impacts of animal memory on seed dispersal

“…A more complex but flexible system is the use of a cognitive map in which the goal is defined by its spatial relation to a number of landmarks (O'Keefe and Nadel 1978), thus the loss of a single landmark does not alter success; however, the loss of multiple cues in a disrupted habitat could result in an animal failing to return successfully to a resource. This is considered a highly efficient navigational mechanism that allows an animal to cope with some environmental change; however, it imposes a high burden on memory load (Dale and Innis 1986). Alternatively, animals can navigate using a response-based strategy in which a goal is reached by performing a specific sequence of responses (e.g.…”

Variation in arm‐choice strategies of rats in radial‐maze tasks

“…Early studies reported that successive choices were made almost randomly, and neither response chains nor general algorithms were necessary for accurate arm choice (Olton, 1978, for a review). However, subsequent studies found evidence of the strategy of response chains, such as adjacent-arm choices (Dale & Innis, 1986;Yoerg & Kamil, 1982). For example, Roberts and Dale (1981) showed that percentage of the adjacent-arm choices increased to over 90% at the end of training.…”