Thom Herrmann

Problem solving in the rat: Stay vs. shift solutions on the three-table task

Two experiments were conducted to determine the conditions under which a shift problem vs. a stay problem would be easier for animals tested on Maier’s three-table task. When animals were given a prior exploratory experience and a partial feeding during the feeding experience, the stay problem was easier. With a prior exploratory experience and a complete feeding experience, the shift solution was easier. In the absence of prior exploration, rats cannot solve either the stay or shift problem, regardless of the amount of feeding during the feeding experience.

Septum and medial frontal cortex contribution to spatial problem-solving

An attempt was made to contrast the effects of lesions to the medial frontal cortex and septum in two spatial tasks. In the fixed-goal (FG) task, the food was located on the same table throughout testing, and the start table was randomly varied from day to day. In the variable-goal (VG) task, the start table remained constant but the food was randomly distributed on one or the other of the two remaining tables. In both tasks, normal animals performed better than frontal and septal rats whose performance, however, improved over days in the FG, but not in the VG, task. In both tasks, significant improvement within days was found in medial frontal animals, but not in septal animals. Additional analyses revealed that septal animals had a general pattern of disrupted exploration and a tendency to use a response strategy (i.e. to repeat the same response both within and between days) which decreased over days in the FG task. In contrast, medial frontal animals did not demonstrate disrupted exploration nor any response tendency. It is concluded that both septal and medial frontal cortical damage produce a common spatial working memory impairment. However, there is some evidence to suggest that this common memory impairment could result from disruption of distinct mechanisms in septal and frontal animals. It is proposed that medial frontal lesions could affect some specific mechanism related either to attentional processes or to the ability to anticipate future events, whereas septal damage would interfere with the building of comprehensive and flexible spatial memories.

Spatial problem solving by rats: Exploration and cognitive maps☆

Abstract Two experiments were performed in an attempt to examine the contribution of the exploratory experience to performance on Maiers 3-table spatial problem-solving task. In the first experiment, the runway configurations were altered between exploration and testing. It was found that following an initial impairment animals exposed to the altered runway configurations could perform as well as animals not confronted with an altered runway configuration on the test trial. In the second experiment, animals were allowed to explore only elements of the problem space. Exploration of either the runways only or the tables only led to unsuccessful performance on the 3-table task. The results of both experiments were related to current theory of cognitive mapping.

Spatial Problem Solving in a Dual Runway Task by Normal and Septal Rats

The addition of a dual runway configuration did not disrupt the successful performance of normal animals, nor did it improve the deficit of septal rats on the Maier three-table spatial integration task. Both groups of animals displayed a preference for the outside runway configuration during exploration. During testing, however, septal animals retained this preference, whereas normal subjects attempted solution by using the inside runway configuration. This fact, in addition to the apparent lack of a habituation pattern during exploration, suggests that septal animals do not acquire a spatial representation of the test situation. It is suggested that the inability of septal rats in spatial situations is due to an inability to form rather than an inability to use spatial maps.

Comparison of septal and fornical lesioned rats performance on the maier three table reasoning task

Abstract Neither septal nor fornix lesioned rats were able to successfully perform the Maier 3 table reasoning task. Detailed analysis of the performance patterns of both groups reveal a common feature of primary dependence on directional responses at the choice point. This response strategy, as opposed to the spatial strategy attributed to normal animals, does differentiate between the two lesion groups. Septal lesioned subject show a dependence on a preferred or dominant direction of turning at the choice point both within and over trials. Fornical lesioned animal demonstrate the same pattern but only over trials. In addition, fornical lesioned rats tend to continue responding even though they had successfully reached the goal table. It is argued that fornical lesioned rats may not be able to use spatial information while septal rats who evidence repetitive errors, made by alternating between environmental locations, may attempt to acquire and unsuccessfully use spatial information.

Role of the medial and lateral septum in a variable goal spatial problem solving task

Rats with lesions to the medial (MS) or lateral septal (LS) nuclei were compared to normal controls (CNT) in the acquisition of a spatial working memory task. In this task, animals were first allowed to explore the unbaited three-table apparatus before being fed on one of the two possible goal tables. Animals were then tested on their ability to return to the table where they just had been fed. Only rats with medial septal damage were clearly impaired on this problem, an impairment that dissipated over days. In contrast, the performance of LS rats was not significantly different from controls. During the second phase of the experiment, the same animals received either atropine sulphate (50 mg/kg, IP), atropine methylnitrate (50 mg/kg, IP), or an equivalent volume of saline. Atropine sulphate produced a sharp decrease in performance by all subjects. Meanwhile, atropine methylnitrate produced a mild temporary deficit only in LS rats. Overall, these results confirm that the medial septum plays a crucial role in the acquisition of problem solving. In addition, these results also suggest that the lateral septum may play a possible role in some form of spatial behavior easily disrupted by atropine methylnitrate.

Visual cues fail to attenuate deficits on a spatial-integration task following septal or fornical damage

An attempt was made to reduce the deficit produced by a septal and/or fornical lesion on the 3-table reasoning task through the addition of a visual cue. This procedure has previously been used to ameliorate deficits produced by these lesions in a variety of instrumental tasks. When the cue was used to indicate a particular location it had no effect on performance. When the cue was used to indicate the presence and location of food, the performance of fornically damaged subjects improved and the performance of control subjects dropped. However, the performances of both groups were comparable to levels achieved when the task was made into a discriminative learning situation. These results emphasize the qualitative distinction between spatial integration and spatial discrimination performance and gives support to the suggestion that the fornix is involved in spatial integration processes. On the other hand, the performance of septal-lesioned subjects was unaffected by the addition of the cue, suggesting a more severe deficit than loss of spatial integrative ability.

Spatial problem solving in the rat following medial frontal lesions

Rats with medial frontal lesions were unable to perform as successfully as normal rats on the Maier 3-table spatial reasoning task. Performance did not improve with repeated testing. Instead, the test-trial performance of medial frontal animals was characterized by the use of a directional response (i.e., body turn) strategy at the choice point. Normal rats habituated (i.e., decreased the number of table entries) within the first few minutes of the daily exploratory period. Although medial frontal rats initially did not display this habituation pattern, they did develop this habituation pattern over blocks of trials. The presence of the habituation pattern has been used as evidence to indicate that the table-entry behavior reflects exploratory rather than general activity levels. The fact that medial frontal animals do show a habituation pattern but are unable to solve the problem suggests that such animals are able to acquire spatial information but are unable to use it.

Faculty genealogies in five Canadian Universities: Historic‐graphical and pedagogical concerns

For those who are both scholars and teachers of the history of psychology, a dilemma arises concerning the historiographic versus pedagogic value of institutional genealogies. As part of the undergraduate History of Psychology course, faculty genealogies were constructed at five Canadian psychology departments (Calgary, Guelph, Toronto, Western Ontario and York); an operational definition of “Ph.D. supervisor” represented mentor-student “institutional” linkages. Seventy-five per cent of the 212 faculty were traceable to nine pioneer figures such as Wilhelm Wundt or William James. In contrasting historiographic pitfalls with pedagogic merits, we suggest that integrating a reflexive and critical examination of histriographic problems may tip the scales in favour of pedagogic reasons for conducting such genealogical research.

Summation of excitatory and inhibitory control produced by traditional tone-shock contingencies and autocontingencies

Previous research has demonstrated that rats can use unsignaled shock to predict subsequent periods free from shock. This shock-no shock stimulus arrangement, termed an autocontingency, has appeared less likely to exert behavioral control when a traditional tone-shock contingency was simultaneously available. The present research examined the generality of CS-US contingency dominance in a conditioned suppression paradigm by using a summation test in which “probe” stimuli derived from tone-shock contingencies were superimposed upon responding maintained by an autocontingency. In experiment 1, an inhibitory CS accelerated responding only when responding was normally suppressed by the autocontingency. In experiment 2, an excitatory CS failed to yield conditioned suppression during an inhibitory (accelerative) period produced by the autocontingency. Unlike our previous findings (e.g., Davis, Memmott & Hurwitz, 1975), these results do not support a general notion of tone-shock contingency dominance over autocontingencies. Behavioral control by autocontingencies appears robust and “holds its own” in summation with both excitatory and inhibitory CSs derived from traditional contingencies.