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1.
75 mongrel cats learned a shape discrimination with 0, 1, or 2 irrelevant cues. They were then subjected to either sham operations, ablation of the marginal and splenial gyri, or lesions in the extramarginal (EM) cortex. The 32 EM cats comprised 4 groups, 3 with small (EM1), intermediate (EM2), large (EM3) decortications, and a 4th group with both EM lesions and heavy degeneration in the lateral geniculate nucleus (LGN). Ss with marginal or extensive extramarginal lesions were severely impaired in shape and size discrimination. Results show the following: (a) The errors made by marginal gyrus cases increased sharply as a function of the number of irrelevant cues present in shape discrimination training; no other group, including Group EM3, was affected by this variable. (b) Ss with extramarginal ablations and strong LGN degeneration were no more severely impaired than were Ss with comparable extramarginal damage and little or no LGN degeneration. While the nature of the 2 kinds of deficits remains unclear, they seem parallel to those following posterior cortical lesions in monkeys. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

2.
Eight cats with lesions in the posterior temporal (PT) cortex, 7 cats with lesions in the basolateral amygdala (BLA), and 8 intact controls were observed on 8 tests of visual discrimination learning and spontaneous responses to salient visual stimuli. The effects of the 2 lesions were somewhat dissociable. The PT lesions were accompanied by a severe deficit in pattern discrimination learning but no loss in visual tracking or orientation to the silhouette of a threatening cat. The BLA lesions produced a milder and less consistent loss in pattern discrimination but serious defects in tracking and response to the cat silhouette. Both operated groups performed well on the visual cliff. The deficit from PT lesions appeared independent of damage to the geniculocortical system. The parallel of symptoms from PT lesions in cats and inferotemporal lesions in monkeys is discussed. (33 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

3.
16 mongrel kittens with neonatal lesions of the marginal and posterolateral gyri and 20 unoperated controls were reared either in an enriched environment or in laboratory cages. Ss with lesions were inferior to controls with respect to learning mazes and discriminating forms and gratings. This held regardless of whether they were raised in enriched or impoverished conditions. Enrichment did not facilitate form or grating discrimination by either normal or lesioned Ss, although such experience facilitated maze learning by both groups. It is concluded that early enrichment of sensorimotor experience was probably not the cause of the complete sparing of pattern vision after neonatal damage of the visual cortex reported in earlier studies. Task variables and completeness of the lesions are discussed as reasons for sparing of vision. (41 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

4.
Ablation of inferior temporal cortex in the rhesus monkey produces a visual discrimination learning deficit. The severity of this deficit has often been found to be a function of task difficulty. The present paper reports 2 experiments with 25 Macaca mulatta and M. fascicularis on a type of visual discrimination problem that, although difficult, is not sensitive to inferior temporal lesions. Ss with anterior, posterior, and complete inferior temporal lesions were repeatedly unimpaired or only slightly impaired in learning to discriminate a pattern from the same pattern rotated 90° or 180°; yet they were very severely impaired in learning equally or more difficult discriminations of 2 different patterns. This demonstration that discrimination of orientation of patterns is relatively spared after inferior temporal lesions helps specify the pattern-rcognition processes that require inferior temporal cortex. (16 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

5.
27 male rhesus monkeys were tested for pattern discrimination retention and for color discrimination learning, with and without stimulus-response (S-R) separation, following superior colliculus lesions, partial striate cortex lesions, foveal prestriate lesions, or control lesions involving cortical or subcortical structures. Only the prestriate Ss were reliably impaired in pattern retention and in color discrimination tasks without S-R separation. In color discriminations involving S-R separation, collicular Ss were deficient compared either with the controls or with those with striate lesions. These findings suggest that the primate superior colliculus, like prestriate cortex, is involved in visual sampling behavior required by S-R separation, and thus participates in orientation to visual stimuli. (36 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

6.
In turtles, the nucleus rotundus, a dorsal thalamic cell group, is known to receive a massive input from the optic tectum. Electrophysiological and anatomical data indicate that nucleus rotundus has a role in visual functions. To study role, 21 eastern painted turtles (Chrysemys picta picta) were trained in an appetitive situation on a simultaneous intensity discrimination or a simultaneous pattern discrimination. After reaching criterion, most Ss received lesions aimed at nucleus rotundus. Two Ss in the intensity-discrimination group received sham lesions. Following surgery, Ss were retrained and then sacrificed, and the lesion damage in each S was reconstructed. Ss with severe damage to nucleus rotundus were unable to relearn the discriminative task, and those with moderate amounts of damage required more sessions to relearn than they had required preoperatively. Ss with slight damage to nucleus rotundus were unimpaired. For both the intensity- and the pattern-discrimination groups, there was a significant correlation between postoperative performance and amount of damage to nucleus rotundus. Results suggest that nucleus rotundus plays a critical role in visual discriminative functions in the turtle. (57 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

7.
To examine the function of primate visual cortex, the performance of 1 normal control group and 3 operated groups of Galago senegalensis (n?=?12) having bilateral cortical lesions in area 17, the middle temporal area (MT), or areas 18 and 19 (XS) was assessed on tasks measuring visual sensory capacity, search, and learning. Striate lesions produced a reduction in foveal vision and were responsible for deficits only on a complex visual learning task. The lesions of Group MT extended beyond the MT and involved the optic radiations. This resulted in impairments on all visual problems. Ss in Group XS had subtotal lesions of prestriate cortex and were also impaired on each task, but they showed less severe deficits in sensory capacity than Ss in Group MT. It is suggested that the Galago striate cortex plays a major role in the identification and utilization of relevant visual information and that areas 18 and 19 are important in both visual learning and visuospatial analyses. Evidence is provided that the MT is involved in visual search. (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

8.
Tested reversal learning for 2 groups of 85 male C57BL/6J and BALB/cJ mice following a bilateral lesion in either the basolateral, central, lateral, medial, or cortical nucleus of the amygdala. On the 2nd reversal, C57BL/6J Ss with a lesion in the lateral nucleus performed less well than intact controls and operated controls. The BALB/cJ Ss with a lesion in the cortical nucleus performed less well on the 1st reversal than these 2 control groups. Data indicate that effects of specific amygdaloid lesions on learning are not necessarily the same for all strains or stocks within a species, and that lesions simultaneously involving many nuclei may be of limited usefulness in understanding the relationship of the amygdala to reversal learning. (27 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

9.
Reports results of 3 experiments with a total of 59 mongrel and 11 Siamese cats. Extensive ablations of posterior cortex which spared the primary visual areas severely impaired visual pattern discrimination, detour learning, and spatial reversal performance. Lesions in the posterior ecto- and suprasylvian gyri (EP) produced significant deficits in learning multiple object discrimination problems, repeated reversals on spatial or visual cues, and successive visual discriminations. Ss with cortical ablations that did not invade the EP region but did cause damage to the optic radiations were not impaired in reversal learning and were deficient in successive discriminations only when tested with nonsalient cues. Thus, some of the defects shown by EP cats are qualitatively different from the losses in cats with damage to the geniculostriate system. (39 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

10.
To test the hypothesis that posterior inferotemporal cortex and the adjoining foveal prestriate cortex contribute to vision by combining inputs from striate cortex and superior colliculus, a total of 18 rhesus monkeys with combined collicular and partial striate lesions, foveal prestriate-posterior inferotemporal lesions, or subcortical lesions (controls) were tested in a series of visual discrimination tasks. Prestriate-inferotemporal lesions, unlike striate-collicular lesions, consistently impaired retention of a pattern discrimination and produced partial impairments in a size discrimination test. However, prestriate-inferotemporal and striate-collicular lesions produced similar deficits in pattern discrimination learning and no deficits in brightness discrimination learning. The deficits of the striate-collicular monkeys are discussed with regard to the "input-combining" hypothesis and alternative views. (39 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

11.
Evaluated the effects of bilateral lesions of individual laminae of the Wulst on reversal-learning performance in pigeons. After surgery, Ss were trained to perform a simultaneous color discrimination. Once successful discrimination was achieved, the positive and negative stimuli were reversed, and Ss were again trained to criterion. 20 reversals were carried out. A multiple regression analysis indicated that those components of the Wulst that were critical for increasing the numbers of errors on each reversal were the laminae that receive the thalamofugal visual projections (i.e., the nucleus intercalatus of the hyperstriatum accessorium and the hyperstriatum dorsale). Lesions in the other laminae of the Wulst (the hyperstriatum accessorium and the hyperstriatum intercalatus superior) had no effect on errors. There was no evidence of an increase in either perseverative errors or position habits in the Ss with lesions, suggesting that the reversal deficits were not likely to be due to perseveration, attentional impairment, or inappropriate processing of spatial information. The deficit may have been produced by excessive interference between learning in a given session and learning in previous sessions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

12.
Performance by cats with lesions of the visual cortex made in infancy or adulthood was examined on tasks of visually guided behavior that do not require specific training. Cats with lesions confined to areas 17, 18, and 19 made during the 1st postnatal week showed more sparing of function on a visual cliff, at orienting to targets suddenly appearing in the visual field, and at optokinetic nystagmus than did cats with equivalent damage incurred as adults. Cats with lesions that included areas 17, 18, 19 and most of the contiguous visual areas were severely impaired at all tasks whether the lesions were incurred neonatally or in adulthood. These findings suggest that sparing of vision after neonatal lesions of cortical areas 17, 18, and 19 is not confined to pattern learning tasks and that remaining lateral cortical visual areas are importantly involved in such sparing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

13.
Evaluated nest building, pup retrieving, and pup survival and growth in 11 primiparous female CF-1 strain mice and in 36 others with cingulate cortical, neocortical, amygdala, or septal lesions. Ss with neocortical or amygdala lesions showed little or no deficits in maternal behavior. Ss with septal lesions were severely impaired in all aspects of maternal care. These did not build nests, showed a variety of aberrant behaviors during pup retrieving, and their pups died or gained significantly less weight than those of controls. Ss with cingulate cortical lesions retrieved pups more slowly than controls, and retrieving deficits were correlated with the extent of retrograde degeneration found in the anterior thalamic nuclei. (26 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

14.
In Exp I, 97 male Sprague-Dawley albino rats were given 10 light–shock pairings on 2 successive days. At 24–48 hrs following training, groups of Ss received bilateral transection of the cerebellar peduncles, bilateral lesions of the red nucleus (which receives most of the cerebellar efferents), or bilateral lesions of the central nucleus of the amygdala. Controls were sham operated. At 3–4 days after surgery, Ss were tested for potentiated startle (PS [increased acoustic startle in the presence of the light previously paired with shock]). PS was blocked by lesions of the central nucleus of the amygdala but not by transection of the cerebellar peduncles or lesions of the red nucleus. Exp II, in which a visual prepulse test was used with 14 Ss, indicated that the blockade of PS observed in Ss with amygdala lesions could not be attributed to optic tract damage. Exp III, with 20 Ss, demonstrated that the absence of potentiation in Ss with amygdala lesions was not simply due to a lowered startle level ceiling, because these Ss could show increased startle with increased stimulus intensity and with administration of intraperitoneal strychnine, (0.75 mg/kg), a drug that increases startle. Results are consistent with the hypothesis that the amygdala is involved in fear conditioning. (64 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

15.
After watching the performance of a model rat (N = 10), 48 Os (naive male hooded rats) were trained on a visual pattern discrimination. Results show that the observational experience facilitated discrimination learning if the same cue pattern was positive for the model and the O; it retarded learning in Ss trained on the reversal of the observed discrimination. These results depend on the viewing of a model contiguous with the cue pattern. A 2nd type of facilitating effect followed visual exposure to the cue patterns presented without a model S. When such an observational condition involved stimulus change, discrimination learning was facilitated regardless of the cue to be approached. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

16.
Tested 3 rhesus monkeys with lesions of lateral striate cortex (LSC), 4 monkeys with superior colliculus (SC) lesions, and 3 unoperated monkeys for retention of a preoperatively acquired pattern discrimination. The 3 groups of monkeys were then tested in 2-choice, color discrimination tests, 1 involving varying degrees of stimulus–response (S–R) separation and the other, administered several months later, involving various directions of S–R separation. Ss were also tested in a series of 2-choice pattern discriminations, following each of which they were tested for relearning when the patterns were masked with bars or circles. LSC lesioned Ss were moderately retarded in retention of the pattern discrimination, whereas those with SC lesions were not. SC lesioned Ss, but not those with LSC lesions, were impaired in both S–R separation tests, which demonstrates that their deficit was not transient or solely due to a difficulty in shifting the gaze in 1 direction. The LSC Ss, unlike those with SC lesions, were deficient in relearning discriminations between masked patterns. Findings suggest that SC and LSC may be involved in 2 different aspects of attention, respectively: shifting attention (and orientation) from 1 spatial locus to another and maintaining attention on fixated stimuli. (40 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

17.
Investigated performance on visual discrimination problems by 7 control (C) cats, 8 cats with lesions in the posterior temporal (PT) cortex, and 8 with destruction of the central 3-20° of the retina's projection to the marginal (M) gyrus. Group PT was impaired on 7/11 initial learning and transfer tests and on 0/3 retention tests with pattern stimuli and was inferior to Group C on 1/7 object discrimination tasks. No discrimination contingency was more likely than the others to reveal a significant deficit in Group PT. Group M was not impaired relative to Group C on any individual discrimination task. However, it made significantly more total errors on 7 discriminations between complex patterns (embedded or masked figures) than Group C. On 3 discriminations between simple patterns (unmasked figures), Group M made fewer errors than Group C. This pattern of loss is qualitatively similar to but milder than that observed in previous cats with M lesions, probably because the present M lesions were relatively small. Findings indicate that M and PT ablations produce differential impairments in cats, a selective difficulty in differentiating complex patterns after M lesions and a nonselective disruption of pattern discrimination learning after PT lesions. (34 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

18.
Of 9 young adult cats with electrodes implanted in the dorsolateral caudate nucleus, 4 had previously reached criterion on a delayed alternation task. Tested under alternating conditions of stimulation and nonstimulation, these 4 Ss showed a significant performance decline with stimulation. When a marker was placed on 1 response panel, performance under stimulation did not decline. Stimulation did not affect the learning of a visual discrimination. The remaining 5 Ss were trained on delayed alternation with alternating stimulation and nonstimulation conditions. Under stimulation, performance remained near chance levels. These Ss were tested on position learning and reversal, and under unilateral stimulation. Results support the view that the caudate nucleus and prefrontal cortex mediate separate aspects of delayed response behavior. (35 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

19.
12 male rhesus monkeys received bilateral stereotaxic lesions centered in the basolateral, lateral, and dorsal amygdala, or the temporal white matter lying adjacent to the lateral amygdala. Ss were compared with 4 others with control operations. Controls then received total amygdaloid lesions (AMX). AMX Ss exhibited the typical amygdaloid syndrome of hypoemotionality, meat eating, coprophagia, and excessive exploration. In contrast, Ss with subtotal amygdaloid lesions would not eat meat or feces, though they were more willing than controls to investigate inanimate objects. Extreme emotional changes after total amygdalectomy were found only in the S with the largest subtotal lesion. Only Ss that were hypoemotional showed a deficit in learning successive reversals of an object discrimination. This suggests that both the hypoemotionality and the successive reversal deficit arise from the same underlying dysfunction. (31 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

20.
In Exp. I, rats with hippocampal lesions were severely impaired in learning a fixed response sequence in a complex maze. Following subsequent manipulations, it was found that hippocampally damaged rats could learn the sequence as well as cortical and operated control Ss in the presence of highly conspicuous cues. Performance of hippocampally damaged Ss, unlike that of the control groups, deteriorated following removal of the cue used in original learning. In Exp. V, Ss with medial thalamic lesions also exhibited maze-learning impairment, but they benefited less than the hippocampal groups from an enhancement of cue conditions. The hippocampus is discussed in terms of its importance in processing relevant stimulus cues and in the organization of appropriate response strategies. (24 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

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