Near-perfect runs as a learning criterion

Developmental Psychobiology

Harmon

Yü

1985

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Young rats with lesions to either the globus pallidus, substantia nigra, median raphe, or pontine reticular formation have previously been reported to be deficient in learning a wide variety of laboratory tasks. In the current study, weanling rats subjected to one of these lesions were rested for three weeks, then examined for acquisition and extinction of a water-motivated straight alley task, and finally tested on luminous flux discriminations of increasing difficulty. All brain-damaged groups were slower than the controls in extinguishing the alley task and only the median raphe group failed to show an impairment on the discrimination problems. These results and others suggest that the foregoing lesions produce deficits in inhibitory and attentional processes. The possibility is discussed that young rats bearing these lesions might serve as a model for the investigation of the neurobiological and cognitive disturbances underlying certain classes of mental retardation in children.

Section: Deficits In Response Inhibition and Attention 487mentioning

confidence: 99%

Deficits in response inhibition and attention in rats rendered mentally retarded by early subcortical brain damage

Developmental Psychobiology

Harmon

Yü

1985

Self Cite

“…Eight trials were usually given each day with an intertrial interval of 50-75 sec. The criterion of learning consisted of either a "perfect" (Grant, 1946) or a "near-perfect" (Runnels, Thompson, & Runnels, 1968) run of correct responses having a probability of occurrence of .05 followed by at least 75"10 correct responses in the subsequent block of 8 trials given on the next day. (This criterion is especially useful in the study of reversal learning when two or more groups of subjects differ significantly from each other in the rate of original learning-see Thompson et al, 1981.…”

Section: Original Learningmentioning

confidence: 99%

“…Examination of the records of the six occipitalectomized animals involved in the present study revealed that had a 9/10 learning criterion been in force, these animals would have learned the original brightness discrimination problem in an average of 50.0 trials (a mean score comparable to that reported by Horel el al., although higher than that reported by Thompson). However, since these occipitalectomized rats performed the 9/10 run beyond the 19-trial limit to be significant at the .05 level (see Runnels et al, 1968), they were arbitrarily judged not to have learned the discrimination. This ovemii.…”

Section: General Findings Brightness Discrimination Learningmentioning

confidence: 99%

Brain lesions impairing visual and spatial reversal learning in rats: Components of the “general learning system” of the rodent brain

1982

Psychobiology

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The "general learning system" (GLS) is conceived as an ensemble of brain structures essential for normal acquisition of a wide variety of laboratory tasks. Based upon earlier lesion studies, it was reasoned that the components of the rodent's GLS could be identified by determining which lesion placements within the rat brain would lead to defective acquisition of a spatial discrimination habit and its reversal as well as a brightness discrimination habit and its reversal. Of the 11 cortical and subcortical (frontal cortex, parietal cortex, occipital cortex, anterior cingulate cortex, posterior cingulate cortex, rostral caudoputamen, dorsal hippocampus, mammillary bodies, mediodorsal thalamic nucleus, parafascicular nucleus, and substantia nigra) sites investigated in this experiment, only two qualified as components of the GLS-the parafascicular nucleus and the substantia nigra. The possibility that the nigro-parafascicular-striatal complex constitutes a major part of the rodent's GLS is discussed.

“…With an intertrial interval of SO-7S sec, training to the correct arm was continued in one session until the animal reached the criterion of learning. The criterion of learning was defined as the first appearance of a "perfect" (Grant, 1946) or "nearperfect" (Runnels, Thompson, & Runnels, 1968) run of correct responses having a probability of occurrence of less than .OS. (This type of criterion is particularly suitable when investigating retentiveness of a habit in two or more groups of subjects that differ significantly from each other in the rate of originallearning-see Thompson et al, 1981).…”

Section: Methodsmentioning

confidence: 99%

Abnormal learning and forgetting of individual spatial reversal problems in brain-damaged rats

1983

Psychobiology

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Except for amygdaloid lesions and cortical cerebellar ablations, selective destruction of virtually any part of the tel-, di-, mes-, or metencephalon was found to impede spatial reversal learning in the rat. (These data contrast sharply with those reported in recent studies on visual reversal learning in the rat.) Test trials given after learning each reversal problem disclosed significant (or marginally significant) deficits in retention only in those groups sustaining damage to the cingulate cortex, ventral hippocampus, rostral caudoputamen, lateral supraoptic hypothalamus, posterolateral hypothalamus, lateral thalamic complex, mediodorsal thalamus, ventromedial thalamus, parafascicular nucleus, substantia nigra, interpeduncular-central tegmental area, pontomesencephalic reticular formation, or pontine reticular formation. It is proposed that there may be at least three classes of learning (amnesic) disorders observed on any given task: (1) a learning impairment only, (2) a retention impairment only, and (3) both a learning and retention impairment.Huppert and Piercy (1979) have presented evidence suggesting that there may be at least two classes of learning (amnesic) disorders in braindamaged patients. In one, learning is impaired, but retention over time of what has been learned is unimpaired. The second is characterized by an impairment (or no impairment) in learning, but retention over time of what has been learned is impaired.