Showing papers by "Trevor W. Robbins published in 1989"
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TL;DR: A role for the amygdala is indicated in mediating the effects of stimulus-reward associations on behaviour, via an action on dopamine-dependent mechanisms of the ventral striatum, following intra-accumbens amphetamine infusions.
651 citations
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TL;DR: The results of the first experiment showed a selective deficit in both groups of Parkinsonian subjects in their ability to perform an extra-dimensional shift and in the visual search task, the patients were less accurate, but responded with equivalent choice reaction times to those of controls.
540 citations
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TL;DR: The results indicate that the basolateral region of the amygdala may interact with dopamine-dependent processes in the ventral striatum in mediating the control by conditioned reinforcers over instrumental behaviour.
456 citations
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TL;DR: Experiments using explicit conditional visuo-spatial discrimination tasks suggest that similar discriminative properties are preserved following DA depletion from the ventral, but not the dorsal, striatum, which possibly represents a dissociation between stimulus-response and stimulus-reward associative mechanisms.
448 citations
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TL;DR: It was notable that many of the deficits following either ibotenate- or quisqualate-induced lesions lasted for several months after surgery, which makes these preparations suitable for further exploration of the restorative effects of cholinergic treatments.
334 citations
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TL;DR: The lesion transiently attenuated both the speed and impulsivity of responding on the baseline schedule, but did not affect discriminative accuracy, supporting theories of a division of arousal-type processes.
318 citations
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TL;DR: The N. Acc lesion impaired but did not abolish spatial learning in the T-maze and the water maze, which may reflect a role for the N.Acc in the reorganisation of behaviour in response to external change.
241 citations
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TL;DR: It is suggested that quisqualic acid, although also nonspecific in its excitotoxic effects, is nevertheless more selective for producing damage to cholinergic neurons in the ventral pallidum/substantia innominata than ibotenic acid.
164 citations
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TL;DR: Detailed analysis of the behavioural evidence suggested that unilateral striatal dopamine depletion does not produce sensory loss or sensory inattention but rather an output type neglect, perhaps related to hemiakinesia or "intentional neglect", and could be reinstated by pretreatment with alpha-methyl-para-tyrosine, thus suggesting the involvement of presynaptic mechanisms in recovery.
140 citations
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TL;DR: A double dissociation of behavioral effects of lateral and medial striatal damage that can be used to infer the operation of distinct elementary processes of response output within a single task is demonstrated.
Abstract: The relative contributions of the medial and lateral caudate putamen to performance of a visual reaction time task were compared by examining the effects of unilateral ibotenate-induced lesions to these regions in the rat. Different groups of rats were trained to respond either towards (Discrimination 1) or away from (Discrimination 2) unpredictable, brief visual stimuli presented to either side of the head. Lateral striatal lesions produced a strong spatial bias towards the side of the lesion but left the latency for the initiation of responses to the visual cues unchanged. By contrast, the medial striatal lesions resulted in a smaller degree of spatial response bias but a significant slowing of initiation latency to the side contralateral to the lesion. These effects were irrespective of the side of the stimulus presentation and thus represent response-related impairments. The lesions were further dissociated in their effects on responding inappropriately to task requirements. These results demonstrate a double dissociation of behavioral effects of lateral and medial striatal damage that can be used to infer the operation of distinct elementary processes of response output within a single task. They are important not only in demonstrating functional effects of hypothetical segregated parallel corticostriatal loops but also in showing that these loops must interact to produce integrated performance.
116 citations
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TL;DR: Evidence from probe trials in which the visual stimuli were presented separately or simultaneously showed that the impairment was not due to a failure to localize the stimuli in contralateral space but, rather, resulted from a deficit in directing responses in contalateral space.
Abstract: Hungry rats were trained to report the occurrence and location of brief, unpredictable visual stimuli presented to the left of their heads in 1 of 2 response locations. After training, they received unilateral infusions of 6-hydroxydopamine, depleting dopamine throughout the head of the caudate putamen, either on the left or the right side, that is, either ipsilateral or contralateral to the side on which they were required to respond. Following an ipsilateral lesion there were no impairments in localization of the visual discriminanda and there was no lengthening of reaction time. The contralaterally lesioned rats, however, showed considerably lengthened reaction times to both stimuli and a profound bias to the nearer of the 2 response locations. Evidence from probe trials in which the visual stimuli were presented separately or simultaneously showed that the impairment was not due to a failure to localize the stimuli in contralateral space but, rather, resulted from a deficit in directing responses in contralateral space. It is suggested that this may be due to a distortion in the representation of response space.
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TL;DR: The locomotor hyperactivity induced by isolation was also specific to rearing conditions and the inverse relationship between water consumption on the last day of testing and plasma corticosterone levels observed in both the socially-reared and socially-housed rats was absent.
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TL;DR: It is concluded that ibotenic acid lesions of the substantia innominata or to the dorsal globus pallidus affect learning and performance of conditional visual discrimination performance and impair reversal learning without affecting the capacity to discriminate visual events.
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TL;DR: The hypothesis that stereotypy has a coping function which may serve to alter arousal is supported and important differences between the nigrostriatal and mesolimbic dopamine projections in modulating the responsiveness of the neuroendocrine system are suggested.