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  • 1
    Electronic Resource
    Electronic Resource
    Cortex, striatum and cerebellum: control of serial order in a grooming sequence (1992)
    Springer
    Experimental brain research 90 (1992), S. 275-290 
    Details
    ISSN: 1432-1106
    Keywords: Movement ; Sequence ; Basal ganglia ; Frontal cortex ; Cerebellum ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Rats emit grooming actions in sequences that follow characteristic patterns of serial order. One of these patterns, a syntactic chain, has a particularly stereotyped order that recurs spontaneously during grooming thousands of times more often than could occur by chance. Previous studies have shown that performance of this sequence is impaired by excitotoxin lesions of the corpus striatum. In this study we examined whether the striatum is unique in its importance to this behavioral sequence or whether control of the sequence instead depends equally upon the cortex and cerebellum. In two experiments, a fine-grained behavioral analysis compared the effects of striatal ablation to the effects of motor cortex ablation, ablation of the entire neocortex, or ablation of the cerebellum. Cortical and cerebellar aspiration produced mere temporary deficits in grooming sequences, which appeared to reflect a general factor that was nonsequential in nature. Only striatal damage produced a permanent sequential deficit in the coordination of this syntactic grooming chain. We conclude that the striatum has a unique role in the control of behavioral serial order. This striatal role may be related to a number of sequential disorders observed in human diseases involving the striatum.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00227239
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  • 2
    Electronic Resource
    Electronic Resource
    Ground reaction forces in locomoting hemi-parkinsonian rats: a definitive test for impairments and compensations (1999)
    Springer
    Experimental brain research 126 (1999), S. 307-314 
    Details
    ISSN: 1432-1106
    Keywords: Key words Striatal dopamine depletion ; Rat ; Locomotion ; Ground reaction forces ; Gait ; Unilateral ; Kinetic ; Centre of mass
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Hemi-parkinsonian rats have preserved postural reflexes but are impaired in initiation of voluntary movements. Surprisingly, these rats can walk and run, suggesting that they can access some compensatory strategy to overcome the rigidity in their impaired limbs. The purpose of the present experiment was to investigate the locomotor compensations made by hemi-parkinsonian rats by measuring the forces exerted by the limbs on the ground throughout the stride during trotting. Rats with unilateral dopamine depletion produced by injection of 6-hydroxydopamine into the nigrostriatal bundle were trained to run back and forth in an alley for food reinforcement. Ground reaction forces were measured in three orthogonal directions using a force plate embedded in the runway. Rats were also videotaped so that limb movements were synchronized with force recordings. Although locomotion was obviously impaired, the affected limbs could support weight and provide some braking forces. In addition, the impaired hindlimb provided significant propulsive force, and a relatively large laterally directed force. Analysis of vertical movement of the centre of mass suggested that the impaired hindlimb was being used partly as a spring. The most significant abnormalities were seen during the diagonal couplet of the impaired forelimb and the unimpaired hindlimb, partly reflecting the important compensatory role of the unimpaired hindlimb. These results demonstrate that this method is useful in the analysis of hemi-parkinsonian gait and provide insights as to how rats can use an impaired limb to produce weight support and propulsion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050739
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  • 3
    Electronic Resource
    Electronic Resource
    BRAIN PLASTICITY AND BEHAVIOR (1998)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Psychology 49 (1998), S. 43-64 
    Details
    ISSN: 0066-4308
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Psychology
    Notes: Abstract Brain plasticity refers to the brain's ability to change structure and function. Experience is a major stimulant of brain plasticity in animal species as diverse as insects and humans. It is now clear that experience produces multiple, dissociable changes in the brain including increases in dendritic length, increases (or decreases) in spine density, synapse formation, increased glial activity, and altered metabolic activity. These anatomical changes are correlated with behavioral differences between subjects with and without the changes. Experience-dependent changes in neurons are affected by various factors including aging, gonadal hormones, trophic factors, stress, and brain pathology. We discuss the important role that changes in dendritic arborization play in brain plasticity and behavior, and we consider these changes in the context of changing intrinsic circuitry of the cortex in processes such as learning.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1146/annurev.psych.49.1.43
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  • 4
    Electronic Resource
    Electronic Resource
    Chronic levodopa therapy does not improve skilled reach accuracy or reach range on a pasta matrix reaching task in 6-OHDA dopamine-depleted (hemi-Parkinson analogue) rats (2001)
    Oxford, UK : Blackwell Science Ltd
    European journal of neuroscience 14 (2001), S. 0 
    Details
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: l-dopa therapy reverses some but not all of the motor deficits in human Parkinson patients. Although a number rat analogues of human Parkinson's disease have been developed for evaluating the efficacy of drug therapies, it is not known whether l-dopa has a similar selective action on the motor symptoms in the rat models. To examine the effectiveness of l-dopa in reversing the motor deficits in rats, we administered 6-OHDA unilaterally to produce hemi-Parkinson rats, which were then trained to reach for food using either their impaired (contralateral to the lesion) limb or their good (ipsilateral to the lesion) limb. To assess the skill, accuracy and range of limb movement, rats reached for pasta from a horizontal array of 260 vertically orientated pieces of pasta. The number and location of pasta pieces taken from this matrix was calculated and the qualitative aspects of the reaching movements were rated. The quantitative data on pasta sticks retrieved indicated that forelimb extension and movement radius around the shoulder joint was reduced by 6-OHDA treatment and did not improve after chronic l-dopa treatment. The qualitative analysis showed that grasping patterns, paw movements and body movements impaired by the lesion were also not improved by l-dopa treatment. These findings are the first in the rat to suggest that whereas l-dopa has a general activating effect on the rat's whole-body movements, as displayed in contralateral rotation, its effectiveness does not extend to skilled forelimb movements. The results are discussed in relationship to the idea that the restoration of some skilled movements may require normal synaptic function.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.0953-816x.2001.01615.x
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  • 5
    Electronic Resource
    Electronic Resource
    NMDA lesions of Ammon's horn and the dentate gyrus disrupt the direct and temporally paced homing displayed by rats exploring a novel environment: evidence for a role of the hippocampus in dead reckoning (2003)
    Oxford, UK : Blackwell Science, Ltd
    European journal of neuroscience 18 (2003), S. 0 
    Details
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Dead reckoning, a form of navigation used to locate a present position and to return to a starting position, is used by rats to return to their home base. The present experiment examined whether dead reckoning is displayed by rats during their first exploratory excursions in a novel environment and also examined whether the behaviour requires the integrity of the cells of the hippocampus. Experimental rats, those with NMDA (N-methly d-aspartate) lesions of Ammon's horn and the dentate gyrus, and control rats could leave a cage to explore a large circular table under light and dark conditions. Home base behaviour, use of olfactory cues, and thigmotaxic- based navigation were evaluated. Temporal, topographical and kinematic analyses were conducted on the first three exploratory excursions that extended at least halfway across the table. Groups did not differ in numbers of exits from the home base, lingering near the home base, distance travelled, or the use of surface cues as might be exemplified by thigmotaxic and olfactory behaviour. Temporal, topographical and kinematic reconstructions of homing behaviour, however, indicated that control rats, but not hippocampal rats, made direct high velocity return trips to the home base in both the light and the dark. Peak velocity of the trips occurred at the trip midpoint, independent of trip distance, suggesting the movements were preplanned. These results are discussed in relation to the ideas that dead reckoning is used in the homing of exploring rats and that this form of navigation involves the hippocampus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1460-9568.2003.02772.x
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  • 6
    Electronic Resource
    Electronic Resource
    Red nucleus lesions impair overground locomotion in rats: a kinetic analysis (2000)
    Oxford, UK : Blackwell Science Ltd
    European journal of neuroscience 12 (2000), S. 0 
    Details
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The red nucleus is a prominent brainstem nucleus in mammals which is thought to be involved in production of skilled limb movements. The presence of the red nucleus and associated rubrospinal tract in animals that do not produce skilled limb movements, however, suggests that these structures might also be involved in control of more general limb actions, such as those occurring during locomotion. The present study investigates this question by measuring the three-dimensional ground reaction forces produced by locomoting rats with unilateral excitotoxic lesions of the red nucleus. Twenty-four to 48 h after the lesion, rats moved with an asymmetric gait during which abnormal braking and propulsive forces were produced during the dual contact time of the forelimb contralateral to the lesion and the ipsilateral hindlimb. Rats did not recover normal symmetrical locomotion within the 55-day duration of the study. The persistent asymmetry produced by red nucleus ablation provides the first unequivocal demonstration that the red nucleus plays a role in ongoing overground locomotion in the rat. Species differences in phylogeny and connectivity of the red nucleus are discussed, as well as the possibility that there is a general compensatory response to unilateral CNS injury in the rat.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1460-9568.2000.00987.x
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  • 7
    Electronic Resource
    Electronic Resource
    Evidence for bilateral control of skilled movements: ipsilateral skilled forelimb reaching deficits and functional recovery in rats follow motor cortex and lateral frontal cortex lesions (2004)
    Oxford, UK : Blackwell Science Ltd
    European journal of neuroscience 20 (2004), S. 0 
    Details
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Unilateral damage to cortical areas in the frontal cortex produces sensorimotor deficits on the side contralateral to the lesion. Although there are anecdotal reports of bilateral deficits after stroke in humans and in experimental animals, little is known of the effects of unilateral lesions on the same side of the body. The objective of the present study was to make a systematic examination of the motor skills of the ipsilateral forelimb after frontal cortex lesions to either the motor cortex by devascularization of the surface blood vessels (pial stroke), or to the lateral cortex by electrocoagulation of the distal branches of the middle cerebral artery (MCA stroke). Plastic processes in the intact hemisphere were documented using Golgi–Cox dendritic analysis and by intracortical microstimulation analysis. Although tests of reflexive responses in forelimb placing identified a contralateral motor impairment following both cortical lesions, quantitative and qualitative measures of skilled reaching identified a severe ipsilateral impairment from which recovery was substantial but incomplete. Golgi-impregnated pyramidal cells in the forelimb area showed an increase in dendritic length and branching. Electrophysiological mapping showed normal size forelimb representations in the lesioned rats relative to control animals. The finding of an enduring ipsilateral impairment in skilled movement is consistent with a large but more anecdotal literature in rats, nonhuman primates and humans, and suggests that plastic changes in the intact hemisphere are related to that hemisphere's contribution to skilled movement.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1460-9568.2004.03751.x
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  • 8
    Electronic Resource
    Electronic Resource
    Home bases formed to visual cues but not to self-movement (dead reckoning) cues in exploring hippocampectomized rats (2005)
    Oxford, UK : Blackwell Science Ltd
    European journal of neuroscience 22 (2005), S. 0 
    Details
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Spatial theory proposes that the hippocampus contributes to exploratory behavior allowing animals to acquire information about their environment. In the present study, the exploratory movements of control rats, bulbectomized (anosmic) rats and hippocampectomized rats using the neurotoxin N-methyl-d-aspartate (NMDA) were monitored on a large circular table without walls and around which visual cues were manipulated. The rats displayed organized spatial behavior in that they developed home bases, one or more places operationally defined as those in which they spent a preponderance of time, in which they moved slowly, and to which they returned after excursions. Control rats and hippocampectomized rats were similar in that they established home bases: (i) adjacent to a proximal stable or moving visual landmark; (ii) in relation to more distant visual room cues; and (iii) in relation to contextually conditioned visual cues. Nevertheless, in exploratory tests given under infrared light, a wavelength to which rats are insensitive, control rats and bulbectomized rats established one or more home bases that were not dependent upon surface (e.g. olfactory) cues, whereas home base behavior was absent/fragmented in hippocampectomized rats. Thus, exploratory behavior, as exemplified by home base behavior, is organized in control and hippocampectomized rats in relation to visual cues, but is not organized in hippocampectomized rats when visual cues are absent. This result is discussed in relation to the idea that the hippocampus contributes to spatial behavior that is dependent upon guidance (dead reckoning) derived from self-movement cues.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1460-9568.2005.04412.x
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  • 9
    Electronic Resource
    Electronic Resource
    Immediate and long-lasting effects of MK-801 on motor activity, spatial navigation in a swimming pool and EEG in the rat (1989)
    Springer
    Psychopharmacology 98 (1989), S. 500-507 
    Details
    ISSN: 1432-2072
    Keywords: Excitatory amino acid ; NMDA antagonist MK-801 ; NMDA antagonist and behavior ; NMDA antagonist and spatial behavior ; Spatial navigation and MK-801
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In a series of experiments, rats received the noncompetitive N-methyl-D-aspartate (NMDA) antagonist MK-801 and measures were made of motor behavior, spatial navigation in a swimming pool, and electroencephalographic (EEG) activity. High doses (0.25–10 mg/kg IV) produced somnolence and akinesia, impaired food consumption, locomotion and swimming, and also impaired navigation to a hidden platform but complete recovery on all measures was obtained between 3 and 5 days postinjection. Lower doses (0.05–0.10 mg/kg, IV) impaired acquisition of a new place response in a swimming pool and produced hyperactivity but did not impair performance on a new cue response or on a well-learned place response. Two forms of hippocampal EEG activity, atropine-sensitive and atropine-resistant EEG were present with the low doses. The results demonstrate that a single dose of MK-801 causes changes in motor behavior and learning lasting a few days, but complete recovery occurs within 5 days of administration of even very high doses of MK-801. They further demonstrate that low doses of the drug selectively impair acquisition of new place responses. Although the general changes in behavior produced by MK-801 suggest that NMDA receptors are involved in many aspects of the control of behavior, the results additionally suggest that NMDA receptors are improtant for place learning.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00441949
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  • 10
    Electronic Resource
    Electronic Resource
    Blockade of hoarding in rats by diazepam: an analysis of the anxiety and object value hypotheses of hoarding (1990)
    Springer
    Psychopharmacology 101 (1990), S. 214-221 
    Details
    ISSN: 1432-2072
    Keywords: Benzodiazepine ; Benzodiazepine and learning ; Benzodiazepine and eating ; Benzodiazepine and food hoarding ; Benzodazepine and rat behavior ; Benzodiazepine and spatial learning ; Food hoarding and anxiety ; Diazepam ; Flumazenil and eating ; Flumazenil and food hoarding ; Flumazenil and rat behavior
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The “security hypothesis” suggests food hoarding by rats serves to preempt attack and therefore might be motivated by “anxiety”. The “object value” hypothesis suggests rats hoard objects that they perceive as valuable as related to some state or need. These hypotheses were evaluated with the anxiolytic drug diazepam, which is purported to both decrease anxiety and increase motivation to eat, and which accordingly either may decrease or increase hoarding. Using a new hoarding paradigm, diazepam (Valium: 0.25–5 mg/kg), was found to produce a dose-related reduction in hoarding that was dependent upon food pellet size and that was reversed by flumazenil (Ro 15-1788), a benzodiazepine receptor antagonist. Diazepam also slowed eating speed, blocked “dodging”, a movement used to initiate hoarding, and impaired spatial navigation in a learning-set swimming pool task. The results fail to support the object value hypothesis of hoarding. Since perception of food size, motivation, motor ability and spatial abilities all probably contribute to successful food hoarding, the results provide several explanations other than, or in addition to, anxiety reduction for the drug's effects on hoarding. Nevertheless, the study provides a number of new sensitive measures of the effects of anxiolytic drugs and new insights into their behavioral effects.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02244129
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