Brain mechanisms and "hypotheses."

Krechevsky, I.

doi:10.1037/h0056416

Cited by 48 publications

(17 citation statements)

References 12 publications

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“…In the rat, Divac (1971), in one of the few studies to date investigating the behavioral effects of lesions in the frontal projection area of the mediodorsal thalamic nucleus (Leonard, 1969), reported deficits in spatial reversal learning following MF but not FP lesions, and it is pertinent to note that Krechevsky's (1935) "spatial hypothesis" area coincides closely with the area of parietal lesions in the present work. Also relevant are three studies showing deficits on the "closed field test of rat intelligence" with lesions essentially within the parietal area lesioned in the present work (Ain et aI., 1969;Forgays, 1952;Thomas, 1966).…”

Section: Discussionmentioning

confidence: 48%

The effects of lesions in the frontal or posterior association cortex of rats on maze III

Thomas

Weir

1975

Psychobiology

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Section: Discussionmentioning

confidence: 48%

The effects of lesions in the frontal or posterior association cortex of rats on maze III

Thomas

Weir

1975

Psychobiology

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“…That the impaired performances seen on these tasks following parietal lesions is not due to some general traumatic effect is indicated by the normal performances seen on the series of black-white discrimination reversals here and on a series of spatial reversals in an earlier study . A previous suggestion (Thomas & Weir) that the parietal cortex in rats may be involved in spatial behavior obviously requires qualification, although it continues to merit consideration due to decrements in maze performances following parietal lesions and to the classic findings of Krechevsky (1935).…”

Section: Discussionmentioning

confidence: 99%

Posterior association cortex lesions in rats: Mazes, pattern discrimination, and reversal learning

Boyd

Thomas

1977

Psychobiology

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Lesions in either the proposed parietal or temporal cortex resulted in a dissociation of deficits, with the former affecting maze performances and "complex" but not "simple" pattern discrimination and the latter affecting performances on a series of reversals and the simple but not the complex pattern discrimination. Discussion considered the role of parietal cortex in spatial behaviors, the adequacy of the simple and complex patterns to differentiate simple sensory from integrative functions, and the unqualified use of Lashley's principles of mass function and equipotentiality. It was also suggested that the rat might provide a useful model for investigations of posterior association cortex.The question of the existence and location of a homolog in rats to the posterior association cortex in primates was discussed recently . It was suggested that one might argue that the rat had a homolog of primate association cortex and that Lashley's work (1941; see Figures 15 and 18) might be used as the guide to the locations of the parietal and temporal association areas in the rat. Thomas and Weir also presented evidence which confirmed Thomas ' (1970) suggestion that Lashley's (1929) early data had provided questionable support for the equipotentiality of neocortical areas for maze III performance. Lesions in the parietal association area and medial frontal lesions resulted in significant performance decrements on maze III, whereas lesions of equivalent size in the frontopolar area did not.The present work was intended to investigate further the possible functions of the proposed parietal and temporal association areas in the rat as well as to assess the generality of findings and conclusions concerning association vs. sensory cortex reached by Diamond and his associates using the tree shrew (Tupaia gUs). To these ends, studies were done using (a) the Hebb-Williams mazes described by Rabinovitch and Rosvold, 1951, and (b) the "simple" and "complex" pattern discriminations and (c) the black-white discrimination reversal problems similar to those described and used by

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“…These analyses attempted to reveal the sequence of strategies or "hypotheses" animals employed during the course of training within problems (Krechevsky, 1935). In our previous work with the present kind of olfactory learning tasks we found that most errors that occur early in discrimination learning are errors of commission, i.e., production of R+ during presentation of S-.…”

Section: Analysis Of Learning Stagesmentioning

confidence: 99%

Normal olfactory discrimination learning set and facilitation of reversal learning after medial-temporal damage in rats: implications for an account of preserved learning abilities in amnesia

Eichenbaum¹,

Fagan²,

Cohen³

1986

J. Neurosci.

211

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Recent evidence of preserved skill learning in patients with "global" amnesia has led to the postulation of a qualitative distinction between functionally separate memory systems, one of which may remain preserved when the other is profoundly impaired. On one account, the separate memory systems support either the learning of declarative knowledge, i.e., facts and associations, or the learning of procedural knowledge, i.e., knowledge that permits the expression of skilled performance without reference to specific facts or associations. In an effort to develop a rodent model of amnesia that illustrates the same distinction between memory systems, rats were trained in a series of discrimination and reversal problems using olfaction, a sensory modality in which they rapidly learn new associations. Rats with bilateral fornix, amygdala, or combined fornix and amygdala damage learned successive two-odor discriminations as quickly as normal and sham-operated control subjects.Furthermore, all groups rapidly acquired the skills of discrimination as revealed in the development of a learning set. Subsequent presentation of a reversal of one discrimination elicited a marked dissociation among groups: Normal rats and rats with amygdala lesions required many more trials to acquire the reversal than to acquire a new discrimination problem, whereas rats with fornix lesions learned the reversal rather easily. A detailed analysis of response strategies suggested that normal rats and rats with amygdala lesions first extinguished the prior response tendencies and then abandoned the learning set skills and treated the reversal much as they did the initial discrimination problem. In contrast, after prior response tendencies were extinguished, rats with fornix lesions were relatively unaffected by the prior cue-associations and treated the reversal much as they would a new discrimination problem. These results distinguish between impaired and spared memory capacities in rodents with amnesia, in conformance with findings on human amnesia.Until recently, investigators involved in developing animal models of amnesia have reported discrepancies in the phenomenology of behavioral impairment after comparable lesions in humans versus animals. Thus, whereas the memory disorder in human amnesic patients is remarkably pervasive, affecting many different categories of material, animals with lesions in the same brain structures suffer a rather more limited behavioral impairment. In particular, early experimenters were dismayed to

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Brain mechanisms and "hypotheses."

Cited by 48 publications

References 12 publications

The effects of lesions in the frontal or posterior association cortex of rats on maze III

The effects of lesions in the frontal or posterior association cortex of rats on maze III

Posterior association cortex lesions in rats: Mazes, pattern discrimination, and reversal learning

Normal olfactory discrimination learning set and facilitation of reversal learning after medial-temporal damage in rats: implications for an account of preserved learning abilities in amnesia

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