The use of intramaze stimuli in the attenuation of the problem-solving deficit of septal animals

Abstract

An attempt was made to ameliorate the deficit in performance shown by septal rats on the Maier three-table task by using either a distinctive visual stimulus insert as a discriminative cue to the route to the daily locus of the food table (Experiment 1) or distinctive visual inserts merely to mark the spatiallocation of each table and the runway leading to that table from the choice point (Experiment 2). When a single stimulus insert consistently identified the food table and the runway to it, regardless of its location in the room, then septals did not differ from shams, and both septals and shams performed better than comparable animals not given the exploratory experience. When the stimulus inserts merely identified the spatiallocation of each table and its corresponding runway, then septals still were impaired relative to normals. More importantly, the fact that normals could perform successfully in Experiment 2 only when they had received a prior exploratory experience indicated that highlighting the spatial location of each table and its runway with a distinctive intramaze stimulus marker does not alter the qualitative character of the three-table task as one requiring spatial integration.A number of neurobehavioral studies (Ellen & Weston, 1983;Herrmann, Black, Anchel, & Ellen, 1978;Herrmann, Black, Doherty, & Ellen, 1980;Rabe & Haddad, 1969;Stahl & Ellen, 1973, 1979 have shown that damage to the septal-hippocampal complex and its interconnections produces profound and long-lasting deficits in performance on the Maier three-table task (Maier, 1932). It will be recalled that on this task animals are required to integrate information concerning the spatial relations existing among the three tables with information concerning the daily locus of food. Each day, the start and food tables are changed so that the animals never learn a particular route to the food or a particular location ofthe food.Despite the marked successes that have been achieved with operant tasks in the attenuation of septal-lesioninduced deficits by means of an external cue that indicates when to respond (Braggio & Ellen, 1976;Ellen & Butter, 1969;Kelsey & Grossman, 1971), a comparable improvement in performance has not been achieved when an external cue is used to signal the locus of the food table in the three-table task. Herrmann et al. (1980) have shown that when a cue light was placed on the feeding table during both the feeding experience and the test trial, septal animals were still unable to return directly to the food table on the test trial.It should be noted that, in the three-table task, the use of the cue light to signal the bai ted table isThe contributions of the following people to the various parts of this study are gratefully acknowledged: Martha Blanc, John CuJlom, Cynthia Johnson, Salvador Macias, and Betty Soteres. The authors' mailing address is: Department of Psychology, Georgia State University, University Plaza, Atlanta, GA 30303.133 not comparable to that of the operant task. In the operant chamber, the cue light...

Low doses of atropine sulfate impair retention of a well-learned spatial task

“…There is strong evidence that the hippocampus constructs and stores cognitive maps of spatial relationships (O'Keefe and Nadel, 1978;Olton, 1978;Ellen and Wages, 1984;Ellen and Weston, 1983). Rats with damage to the septal forebrain, the hippocampus, or the septo-hippocampal pathway show impaired performance on tasks that require spatial learning such as the Olton eight-arm maze (Olton, 1978;Olton et al, 1979) and the Morris water maze (Sutherland et al, 1982 a).…”

Cholinergic blockade effects on spatial integration versus cue discrimination performance.

“…Atropine sulfate had no effects on the Trial 1 performance of the animals in the cue task group. It has been shown previously that performance on the cue task is not dependent on the utilization of spatial information (Ellen & Wages, 1984). In the cue task, the animals merely have to choose, at the intersection of the Y. the table on which they had been fed during the feeding experience; because this pattern was consistently associated with the feeding experience, the animals merely had to perform a visual discrimination and not rely on the spatial properties of the task to ensure successful performance.…”

“…In recent years there has been a focus of attention on the role of limbic forebrain structures in the performance of rats on spatial tasks. Specifically, it has been shown that rats with damage to the septal forebrain, the hippocampus, or their connections are unable to perform successfully on three different spatial tasks: the Olton eight-arm maze (Olton, 1978; Olton, Becker, & Handelmann, 1979), the Morris water maze (Sutherland, Whishaw, & Kolb, 1982), and the Maier three-table problem (Ellen & Wages, 1984; Ellen & Weston, 1983; Rabe & Haddad, 1969).…”

“…In addition, if a distinctive stimulus pattern is consistently associated with the daily location of food, then the three-table spatial task can be converted to a visual discrimination task (Ellen & Wages, 1984). Under these circumstances, animals do not have to respond to the spatial requirements of the task or learn a food-searching strategy.…”