Spatial Discrimination Reversal Research Articles

Spatial and non-spatial discrimination reversal (SDR) learning in the guinea pig

Spatial and non-spatial serial discrimination reversal performance was investigated in guinea pigs over eleven reversals. Difference in learning ability between albino and pigmented strains was not evident on spatial or non-spatial SDR tasks. The guinea pigs' ability to learn rapidly successive spatial and non-spatial reversals with increasing proficiency corresponds well with previous published findings using other mammalian species. These studies also demonstrated behavioural research with the guinea pig to require extended periods of intensive experimental management.

Shift and retention deficits in hippocampectomized and neodecorticate rats

A series of four experiments are reported in which the effect of hippocampal lesions on retention, and the ability to shift responses with changes in reward contingencies was investigated on a spatial discrimination reversal, DRL, and two-choice visual discrimination task. While animals with hippocampal lesions or posterior cortical lesions were deficient in the retention of spatial reversals, the type of error made by each group differed. Contrary to current theories of hippocampal function, animals with hippocampal lesions were not deficient in the abilities required to shift their responses and, in some situations, were actually more flexible than controls. The results are discussed in terms of an inhibition model of hippocampal function. It is suggested that the role of the hippocampus is to inhibit stimulus-response bonds.

Behavioral and brain correlations in early life nutritional deprivation.

Protein-calorie undernutrition in the period of rapid brain growth during gestation and suckling in DBA/2J mice resulted in persistent reduction in body and brain weights, despite normal diet from weaning. No significant changes in brain or spinal cord were observed with light microscopy. Behavioral tests revealed that experimental animals had more frequent feeding with smaller meal size, increased activity in the presence of environmental stimulation, fewer errors in learning spatial discrimination reversals, and more errors in problemsolving maze tests. Activity in dark environment, bar pressing for food on a progressive ratio schedule, and foot shock avoidance conditioning showed no significant difference between control and experimental groups. This behavioral profile supports an hypothesis of higher set-point for arousal resulting from early life nutritional deprivation which influences reversal learning and problem solving.

Differences in spatial discrimination reversal learning between two inbred mouse strains following specific amygdaloid lesions.

Differences in spatial discrimination reversal learning between two inbred mouse strains following specific amygdaloid lesions.

The Overtraining Reversal Effect in Rats: A Function of Task Difficulty

Two experiments were conducted with rats. The first study showed that in the T-maze a brightness discrimination learning problem was more difficult than a spatial learning problem, but in a Ross-maze a brightness problem was less difficult than a spatial task. T-maze brightness and Ross-maze spatial tasks were found to be of equal difficulty. In the second experiment rats were trained either on a brightness or spatial discrimination reversal problem in the Ross-maze. It was found that overtraining facilitated reversal performance in the spatial task but not in the brightness problem. The theoretical implications of these results were discussed.

Successive spatial discrimination reversals in the bat

The performance of five Eptesicus fuscus was studied across a series of nine successive reversals of a spatial discrimination problem. The Ss showed a decrease in mean number of errors across the reversals with an error peak on the third reversal. These results are consistent with the view that improvement across successive reversals (SDRs) is a behavioral indicator of taxonomic differences.

The role of motivational and incentive levels in the determination of successive discrimination reversal (SDR) performance of Chukar partridge

The performances of Chukar partridge on a spatial successive discrimination reversal task was studied at two levels of drive (D) and at two levels of incentive (K). Variation in both D and K led to variation in errors across reversal problems. High D tended to increase errors, while high K yielded a decrement in errors.

Spatial discrimination reversal learning for mice genetically selected for differing brain size: a supplementary report.

Spatial discrimination reversal learning was explored for mice genetically selected for high brain weight and unselected controls with lower brain weights. Control-line Ss escaped from a water maze more rapidly, but high-line Ss made fewer errors and took less trials to reach criterion on the first reversal. Control-line Ss were unable to complete more than 1 reversal, while high-line Ss all completed at least 7 reversals. This positive relation between reversal learning and brain size is consistent with comparisons among species and experiments manipulating brain size by means of drugs or surgery.

Differences in spatial discrimination reversal learning for mice genetically selected for high brain weight and unselected controls.

Spatial reversal learning was explored for mice genetically selected for high brain weight and unselected control mice with lower brain weights. Original learning and two reversals were presented in a water maze. There were no differences for original learning, but the high brain-weight mice were superior to the unselected controls for both reversals. Since all controls had lower brain weights than the highs, it was concluded that these data support a positive relation between brain size and spatial reversal learning.

Discrimination learning and reversal in frontal rats as a function of cue

Abstract Spatial discrimination learning and reversal was studied in sham-operated rats and in rats with frontal ablations. The effect of a light which could function as a cue and/or as a reward in the testing situation was examined. In the sham-operated rats it was found that the rewarding property of the light determined its effect on the spatial discrimination. In the frontal rats it was found that both the rewarding and cue properties of the light determined its effect on spatial discrimination. Although frontal rats learned slower and reversed slower than sham rats under conditions in which no light was present or in which light could neither act as a reward nor as a cue, frontal rats were found to reverse faster than sham rats under conditions in which light could act as a cue. It is concluded that an increased sensitivity to visual stimuli in frontal rats can account for conflicting results of previous studies.

Perseveration in extinction and in discrimination reversal tasks following selective frontal ablations in Macaca mulatta

In order to determine whether the perseverative syndrome exhibited by monkeys with frontal lobe lesions can be fractionated by partial frontal lesions, monkeys with dorsolateral frontal lesions, those with orbital frontal lesions, and those with partial orbital lesions were tested in three tasks: extinction of a food rewarded bar pressing response, spatial discrimination reversals and object discrimination reversals. Perseveration of bar-pressing in extinction was selectively related to the posteromedial or “limbic” portion of orbital frontal cortex. Deficits in object discrimination reversal, on the other hand, were specifically associated with the lateral sector of orbital cortex and possibly to the adjoining ventral portion of dorsolateral frontal cortex as well. Impairment in spatial discrimination reversal was most severe in monkeys with dorsolateral frontal removal. These findings suggest that the perseverative effects of orbital frontal ablation can be fractionated into at least two components and further support the view that dorsolateral frontal cortex is associated with spatial factors.

Successive discrimination reversal (SDR) performances of American alligators and American crocodiles on a spatial task.

There is general agreement that birds and mammals, but not fish, can display error reduction on successive discrimination reversal (SDR) tasks. Reptiles, however, show error reduction on some but not other tasks. To provide further sampling of reptilian SDR performance, two species of crocodilians, the American alligator and the American crocodile, were tested on a spatial discrimination reversal task. Both species displayed error reduction, the alligator being appreciably inferior to the crocodile.

The scaling of relative task difficulty across spatial, brightness, and form successive discrimination reversal (SDR) problems with Capuchin monkeys

The successive reversal performances of Capuchin monkeys assigned to spatial, brightness, and form discrimination tasks were compared to determine relative level of difficulty of each task. Comparison of error, session, and initial error measures all indicated that spatial and form tasks were respectively the easiest and most difficult, with brightness intermediate.

Error Reduction by Pigeons on a Spatial Successive Reversal Task under Conditions of Non-Correction

The performance of 5 pigeons on a successive spatial discrimination reversal task was studied over 29 reversals under conditions of non-correction. A significant reduction of errors occurred following an initial peak error score on the second reversal. Intra-problem error reduction was also significant, with errors remaining only during the initial trials of a session with continued reversal training. Terminal reversal performance approached one-trial reversal.

Spatial Discrimination Reversal and Overtraining in Ferrets

Eight ferrets were trained on a spatial discrimination problem and then on its reversal. Four Ss received 80 overtraining trials prior to reversal, and 4 began reversal the day after reaching criterion. There was no significant difference in trials to reversal criterion, errors, or latencies between the two groups, which supports recent studies with rats.

Spatial Discrimination and Reversal Learning Involving Differential Magnitude of Reinforcement

Three experiments are reported in which choice in the acquisition of spatial discrimination and subsequent reversal learning was based on differential magnitude of reinforcement. Exp. I presented evidence suggesting the operation of an important frustration factor on the smaller-magnitude side in this type of discrimination, and revealed a significant effect of temporal distribution of reinforcement on reversal learning. Exp. II showed that, while differential-magnitude discriminations may be originally acquired as readily as reinforcement-nonreinforcement discriminations, the former are not reversed as readily as the latter, and both types are affected by the administration of forced trials guaranteeing equal response frequencies to the two sides as compared with allowing free choice on all trials. Exp. III, concerned with reversal learning as a function of the magnitude ratio and delay of reinforcement, provided further evidence of poor reversal performance under differential-magnitude conditions, but indicated that performance resembling that in traditional reversal learning may be found if the magnitude ratio is very high.

The facilitation of visual and spatial discrimination reversal by overlearning.

The facilitation of visual and spatial discrimination reversal by overlearning.