59 research outputs found
What Are They Thinking? Scientific Horsemanship and the Mind of the Horse
Horse behavior in an arena is examined to determine their Umwelt, or point of view. When in an arena singly, horses displayed home base behavior, spending their time near the entrance, and excursion behavior, trips into the arena. At home bases, horses paced against the wall, pushed against the gate, looked out, and rolled. On excursions, they displayed a “sniff, look, and loop” pattern; sniffing the ground on the outward leg, looking with ears forward down the arena at the apex, making a faster return with ears back. When free with a pair mate, the area of its excursions expanded and if a pair mate was tethered at the far end of the arena, a horse shifted its home base to that location. When ridden, horses displayed similar sniff, look, and loop behavior centered toward the entrance. Experiments on memory for the arena showed it was good but was reset each day. A model suggests that behavior is shaped by a spatial gradient, in which stress expands in proportion to distance from home, and an exploratory gradient, in which patrolling is a part of each day’s outing. Science-based horsemanship can provide insight into a horse’s view of its world and is relevant to safe horse handling
The Ladder Rung Walking Task: A Scoring System and its Practical Application.
Progress in the development of animal models for/stroke, spinal cord injury, and other neurodegenerative disease requires tests of high sensitivity to elaborate distinct aspects of motor function and to determine even subtle loss of movement capacity. To enhance efficacy and resolution of testing, tests should permit qualitative and quantitative measures of motor function and be sensitive to changes in performance during recovery periods. The present study describes a new task to assess skilled walking in the rat to measure both forelimb and hindlimb function at the same time. Animals are required to walk along a horizontal ladder on which the spacing of the rungs is variable and is periodically changed. Changes in rung spacing prevent animals from learning the absolute and relative location of the rungs and so minimize the ability of the animals to compensate for impairments through learning. In addition, changing the spacing between the rungs allows the test to be used repeatedly in long-term studies. Methods are described for both quantitative and qualitative description of both fore- and hindlimb performance, including limb placing, stepping, co-ordination. Furthermore, use of compensatory strategies is indicated by missteps or compensatory steps in response to another limb’s misplacement
Arm and hand movement: current knowledge and future perspective
Sherpa Romeo green journal: open access[No abstract available]Ye
Complete and Partial Lesions of the Pyramidal Tract in the Rat Affect Qualitative Measures of Skilled Movements: Impairment in Fixations as a Model for Clumsy Behavior
Little is known about prenatal and perinatal
brain injury resulting in subsequent clumsy
behavior in children. One candidate motor system
is the pyramidal tract. The tract traverses the
entire central nervous system and, through direct
and indirect connections to the brainstem and
spinal cord sensory and motor nuclei, is involved
in the learning and execution of skilled movements.
Here, rats, either naive or pretrained on a
number of motor tasks, were assessed for acute
and chronic impairments following complete or
incomplete pyramidal tract lesions. Postsurgery
rats with complete lesions were impaired on the
qualitative measures of limb aiming, supination,
and posture. Impaired movements require
fixations, complementary movements in different
body segments. The impairment in fixations was
manifest acutely and underwent no improvement
with subsequent training/testing. The finding that
complete and partial pyramidal tract lesions
produce chronic impairment in fixations provides
insight for understanding clumsy behavior in
humans and its potential remediation via specific
training in making fixations
Cortex, striatum and cerebellum: control of serial order in a grooming sequence
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.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46562/1/221_2004_Article_BF00227239.pd
Different evolutionary origins for the reach and the grasp: an explanation for dual visuomotor channels in primate parietofrontal cortex
Sherpa Romeo green journal; open accessThe Dual Visuomotor Channel Theory proposes that manual prehension consists of two
temporally integrated movements, each subserved by distinct visuomotor pathways in
occipitoparietofrontal cortex. The Reach is mediated by a dorsomedial pathway and transports
the hand in relation to the target’s extrinsic properties (i.e., location and orientation).
The Grasp is mediated by a dorsolateral pathway and opens, preshapes, and closes the
hand in relation to the target’s intrinsic properties (i.e., size and shape). Here, neuropsychological,
developmental, and comparative evidence is reviewed to show that the Reach
and the Grasp have different evolutionary origins. First, the removal or degradation of
vision causes prehension to decompose into its constituent Reach and Grasp components,
which are then executed in sequence or isolation. Similar decomposition occurs
in optic ataxic patients following cortical injury to the Reach and the Grasp pathways and
after corticospinal tract lesions in non-human primates. Second, early non-visual PreReach
and PreGrasp movements develop into mature Reach and Grasp movements but are only
integrated under visual control after a prolonged developmental period. Third, comparative
studies reveal many similarities between stepping movements and the Reach and
between food handling movements and the Grasp, suggesting that the Reach and the
Grasp are derived from different evolutionary antecedents. The evidence is discussed in
relation to the ideas that dual visuomotor channels in primate parietofrontal cortex emerged
as a result of distinct evolutionary origins for the Reach and the Grasp; that foveated vision
in primates serves to integrate the Reach and the Grasp into a single prehensile act; and,
that flexible recombination of discrete Reach and Grasp movements under various forms
of sensory and cognitive control can produce adaptive behaviorYe
Recovery from lateralized neocortical damage: dissociation between amphetamine-induced asymmetry in behavior and striatal dopamine neurotransmission in vivo
It has been hypothesized that neocortical damage is accompanied by secondary changes in other brain areas (the shock or diaschisis of von Monakow), which contributes to initial non-specific behavioral depression. The relation between behavioral changes and dopamine (DA), serotonin (5-HT), and their metabolites, measured with intracerebral microdialysis in freely moving rats and by tissue assay postmortem, was examined during postsurgical recovery from unilateral hemidecortications. Rats were tested for rotational asymmetry and extracellular concentration of DA was measured both during rest and after amphetamine (1.5 mg/kg). It was found that: (1) during the first few postsurgical days the hemidecorticate rats rotated ipsilateral to their lesions after amphetamine but thereafter on tests given up to 121 days postsurgery there was no asymmetry in rotation; (2) there were no asymmetries in the concentration of DA or its metabolites at any time after surgery; (3) the 5-HT metabolite 5-hydroxyindoleacetic acid (5-HIAA) was elevated acutely for a few days following surgery; (4) during the first 3 postoperative days, both baseline extracellular 3,4-dihydroxyphenylacetic acid (DOPAC) and amphetamine-induced DA release were significantly elevated bilaterally. These findings demonstrate that the acute behavioral asymmetry in rotation produced by hemidecortication is not related to unilateral changes in striatal DA activity and its metabolites. Thus, the behavioral asymmetries might be related to other striatal changes (i.e. 5-HIAA) or other damage, such as to the corticospinal projections of the lesioned hemisphere. Nevertheless, unilateral lesions did produce acute bilateral increases in DA levels, which may be a correlate of generalized neural shock produced by the lesion.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/30208/1/0000598.pd
Independent development of the reach and the grasp in spontaneous self-touching by human infants in the first 6 months
Sherpa Romeo green journal: open accessThe Dual Visuomotor Channel Theory proposes that visually guided reaching is a composite of movements, a Reach that advances the hand to contact the target and a Grasp that shapes the digits for target purchase. The theory is supported by biometric analyses of adult reaching, evolutionary contrasts, and differential developmental patterns for the Reach and the Grasp in visually guided reaching in human infants. The present ethological study asked whether there is evidence for a dissociated development for the Reach and the Grasp in nonvisual hand use in very early infancy. The study documents a rich array of spontaneous self-touching behavior in infants during the first 6 months of life and subjected the Reach movements to an analysis in relation to body target, contact type, and Grasp. Video recordings were made of resting alert infants biweekly from birth to 6 months. In younger infants,self-touching targets included the head and trunk. As infants aged, targets became more caudal and included the hips, then legs, and eventually the feet. In younger infants hand contact was mainly made with the dorsum of the hand, but as infants aged, contacts included palmar contacts and eventually grasp and manipulation contacts with the body and clothes. The relative incidence of caudal contacts and palmar contacts increased concurrently and were significantly correlated throughout the period of study. Developmental increases in self-grasping contacts occurred a few weeks after the increase in caudal and palmar contacts. The behavioral and temporal pattern of these spontaneous self-touching movements suggest that the Reach, in which the hand extends to make a palmar self-contact, and the Grasp, in which the digits close and make manipulatory movements, have partially independent developmental profiles. The results additionally suggest that self-touching behavior is an important developmental phase that allows the coordination of the Reach and the Grasp prior to and concurrent with their use under visual guidance.Ye
Effects of neonatal forebrain noradrenaline depletion on recovery from brain damage: Performance on a spatial navigation task as a function of age of surgery and postsurgical housing
The experiments examined the contributions of forebrain noradrenaline and environmental enrichment to recovery of place navigation ability in rats after hemidecortication in infancy or adulthood. Noradrenaline depletion did not affect recovery from neonatal hemidecortication, although the early hemidecortications did allow sparing of function relative to adult operates. Noradrenaline depletion also failed to attenuate the positive effects of enriched housing on otherwise normal rats. Noradrenaline depletion did retard recovery of adult hemidecorticate rats housed in standard laboratory cages, but it did not retard recovery of adult hemidecorticate rats housed in enriched environments. The results suggest that noradrenaline is importantly involved in enhancing recovery from brain damage when other sources of compensation (e.g., neonatal injury, enriched environment) are absent.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25995/1/0000061.pd
Effects of Emerita brasiliensis flour supplementation on normotensive (Wistar) and spontaneously hypertensive rats (SHR)
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