Components Of Locomotion Research Articles

Lower Limb Kinetic And Energetic Factors Associated With Stride Length In Healthy Human Gait

Stride length (SL) is a fundamental component of locomotion and has been widely reported as a descriptive quantity. Despite its importance the underlying factors causing SL remain fundamentally unknown. We propose 1) hip, knee and ankle muscle groups each contribute significantly to SL and 2) SL is modulated through a coordinated synergy of torques and powers across lower limb joints and muscles. PURPOSE: Identify the relationships among lower limb joint torques and powers and SL in walking in 10 healthy adults. METHODS: SLs and lower limb joint torques and powers were assessed for 20 trials of various SLs per subject. Joint torques and powers were correlated with SL for the entire sample (over all subjects and trials) and for individual subjects (over trials). Means of the subjects' values were derived through RMS averaging. RESULTS: SLs were evenly distributed over a range of 1.08 to 2.45 m (0.63 to 1.41 body heights). Relationships with SL were similar for torques and powers for the entire sample and for individual subjects. Compared to those for the entire sample however, individual subject relationships were stronger at all joints and substantially different at the hip. Individual results showed torque and power were modulated similarly across joints with SL and the summed torques and powers across joints explained most of the SL variance (i.e. ∼87%). CONCLUSIONS:Mechanical output of hip, knee and ankle muscles contributed to SL and the highest correlations for summed joint torques and powers showed that SL was modulated through a coordinated synergy of torques and powers across joints and muscle groups. Supported by NIH R01AG024161. Correlation Coefficients (r) and Coefficients of Determination (r2) between SL and torques and powersTable

Morphological correlates of emotional and cognitive behaviour: insights from studies on inbred and outbred rodent strains and their crosses

Every study in rodents is also a behavioural genetic study even if only a single strain is used. Outbred strains are genetically heterogeneous populations with a high intrastrain variation, whereas inbred strains are based on the multiplication of a unique individual. The aim of the present review is to summarize findings on brain regions involved in three major components of rodent behaviour, locomotion, anxiety-related behaviour and cognition, by paying particular attention to the genetic context, genetic models used and interstrain comparisons. Recent trends correlating gene expression in inbred strains with behavioural data in databases, morpho-behavioural-haplotype analyses and problems arising from large-scale multivariate analyses are discussed. Morpho-behavioural correlations in multiple strains are presented, including correlations with projection neurons, interneurons and fibre systems in the striatum, midbrain, amygdala, medial septum and hippocampus, by relating them to relevant transmitter systems. In addition, brain areas differentially activated in different strains are described (hippocampus, prefrontal cortex, nucleus accumbens, locus ceruleus). Direct interstrain comparisons indicate that strain differences in behavioural variables and neuronal markers are much more common than usually thought. The choice of the appropriate genetic model can therefore contribute to an interpretation of positive results in a wider context, and help to avoid misleading interpretations of negative results.

Travel path conditions dictate the manner in which individuals avoid collisions

The ability to perceive the motion of approaching objects and to make appropriate adjustments to avoid collisions is an essential component of safe locomotion through the environment. No previous study has looked at actual behavioural responses in a realistic collision avoidance task. We investigated individuals’ collision avoidance behaviour with an approaching object in order to understand the visual information used to accomplish the task. We found that when individuals were walking towards a goal without any restrictions, a change in travel path occurred at the same time, independent of the object's approach velocity. However, the lateral rate of change in the travel path was significantly slower for the slower approach velocity. We found that when a restriction was present along the travel path, individuals were exposed to the object's properties for longer and a change in travel path occurred later for slowest approaching velocities than for the fastest approaching velocities. The results suggest that individuals are capable of determining TTC from an approaching object during actual self-motion, but the motor parameter it modulates is different for different circumstances.

Morphine reward in dopamine-deficient mice

Dopamine has been widely implicated as a mediator of many of the behavioural responses to drugs of abuse. To test the hypothesis that dopamine is an essential mediator of various opiate-induced responses, we administered morphine to mice unable to synthesize dopamine. We found that dopamine-deficient mice are unable to mount a normal locomotor response to morphine, but a small dopamine-independent increase in locomotion remains. Dopamine-deficient mice have a rightward shift in the dose-response curve to morphine on the tail-flick test (a pain sensitivity assay), suggesting either a decreased sensitivity to the analgesic effects of morphine and/or basal hyperalgesia. In contrast, dopamine-deficient mice display a robust conditioned place preference for morphine when given either caffeine or l-dihydroxyphenylalanine (a dopamine precursor that restores dopamine throughout the brain) during the testing phases. Together, these data demonstrate that dopamine is a crucial component of morphine-induced locomotion, dopamine may contribute to morphine analgesia, but that dopamine is not required for morphine-induced reward as measured by conditioned place preference.

Movements at the low back during normal walking

We present a technique for measuring the kinematics of the functional low back during normal gait. We have used a similar technique previously to measure low back movement simultaneously with hip, knee, and ankle movement during the toe-touching manoeuvre. We noted that movements at the low back were biphasic. The greatest low back movements were found to occur in the transverse plane (mean = 23 degrees), whereas a mean of 17 degrees movement occurred in the coronal plane and only 5 degrees movement in the sagittal plane. These findings confirm, using a non-invasive technique, that there are significant ranges of movement at the low back during walking and lend some support to the theory that rotational movement at the low back is a major component of human locomotion.

Retraction in amoeboid cell motility powered by cytoskeletal dynamics.

Cells crawl by coupling protrusion of their leading edge with retraction of their cell body. Protrusion is generated by the polymerization and bundling of filaments, but the mechanism of retraction is less clear. We have reconstituted retraction in vitro by adding Yersinia tyrosine phosphatase to the major sperm protein-based motility apparatus assembled from Ascaris sperm extracts. Retraction in vitro parallels that observed in vivo and is generated primarily by disassembly and rearrangement of the cytoskeleton. Therefore, cytoskeletal dynamics alone, unassisted by conventional motors, are able to generate both of these central components of amoeboid locomotion.

The validity of the GaitRite and the Functional Ambulation Performance scoring system in the analysis of Parkinson gait1

The purpose of this study was (1) to determine the validity of the GaitRite System in detecting footfall patterns and selected gait characteristics of person with early stage Parkinson's disease (PD) and (2) to investigate whether the Functional Ambulation Performance (FAP) scoring system is a valid tool to distinguish between selected gait characteristics of patients with early stage Parkinson's disease and similar age of non-impaired individuals. The FAP score is a quantitative means of assessing gait based on specific spatial and temporal gait parameters. 11 volunteers with idiopathic Parkinson's disease, (mean age = 74.3), and 11 age matched volunteers, (mean age = 70.3), with no history of neurological disorder participated in the study. The non-impaired control group were not matched in age and sex but of similar age and males and females were represented in the control group. Temporal and spatial parameters of gait were analyzed for both preferred- speed and fast-speed walking using the computerized GaitRite system. The system integrates specific components of locomotion to provide a single, numerical representation of gait, the Functional Ambulation Performance Score (FAP) score. The most powerful and discriminating variable between Parkinson's and non-impaired groups for both walking speeds was the mean normalized velocity (MNV). Which is velocity divided by leg length. The MNV was 0.83 for PD at preferred walking speed and 1.14 at fast speed, the non-impaired group preferred-speed group walking was 1.33, while fast-speed walking MNV was 1.70. Note the fast walking of PD was slower than the preferred velocity of the non-impaired group. For preferred-speed walking, all gait variables analyzed in the study were different between the two groups beyond the p < 0.05 level of confidence with the single exception of right stance percentage. For fast-speed walking, three of the entered variables did not discriminate between the two groups: the fast walking FAP score, left fast-walking cadence, and right fast-walking single support percentage. Our results indicate that persons with Parkinson's disease (PD) attain a significantly lower FAP score when ambulating at their preferred rate and demonstrate shorter step length and a longer step time than the age matched non-impaired group during both preferred and fast velocities of walking. Stance duration and double support duration were increased for the Parkinson's population, whereas single support duration, mean cadence, and heel-to-heel base of support were markedly reduced for both walking speeds. The FAP score was significantly different from the non-impaired control group for preferred-speed walking. These results indicate that the GaitRite system can be useful in detecting footfall patterns and selected time and distance measurements of persons with early stage Parkinson's disease and the FAP score discriminates between the PD population and the non-impaired controls when walking at preferred rate but not at fast walking.

Locomotion and depression. Clinical and physiological aspects of gait alterations in Parkinson's disease and major depression

Behavioral disturbances of patients with major depression manifest in various motor domains and are relevant for differential diagnosis, therapeutic interventions, as residual symptoms and possibly early manifestation of Parkinson's disease. Alterations of gait as the main component of locomotion are a clinically well-known motor phenomenon of depressed patients. Therefore, pathophysiology of gait disturbances, different methods to analyze gait and empirical findings in patients with major depression are summarized. The current literature was examined including information of manufacturers, Medline, PubMed, PsychLIT and Excerpta Medica. Findings in healthy subjects, in Parkinson's disease, and in major depression are discussed in detail regarding specificity and clinical relevance. Kinematic analysis of gait regulation by videography, ultrasound, opto-electronic measures reveals information about disturbances in central nervous motor programming. Only few studies exist about quantitative data of gait alterations in patients with major depression. Results indicate disturbances in functions of the basal ganglia. Analysis of gait using modern technology yields information about cortical and subcortical dysfunctions. Empirical findings in major depression need further investigation regarding their relevance as residual symptoms, as response predictors, and as risk factors for manifestation of Parkinson's disease.

Heading perception and the allocation of attention

A central theme in previous studies of heading judgements has been whether the retinal flow field can be decomposed to recover the translation component of locomotion when flow also contains the effects of gaze rotation. We explored not just the effect of moving gaze, but also moving attention away from the locomotor path by presenting the case of fixating a road sign and completing different attentional tasks during locomotion. Heading errors increased significantly with attentional load, in the absence of extra-retinal gaze information. When we introduced extra-retinal gaze information with the same tasks this resulted in a significant improvement in heading judgements. These results lead us to question whether the decomposition argument translates to real-world judgements of locomotor heading. If observers need to closely attend to roadside information it seems that decomposition is ineffective, whereas if they have the latitude to alternate gaze it is unnecessary.

Long range seismic characteristics of Asian elephant (Elephus maximus) vocalizations and locomotion

Seismic components of Asian elephant (Elephus maximus) vocalizations and locomotion were recorded at a range of distances. To study the properties of sound attenuation in the ground, a string of four geophones was placed at approximately 30 m intervals from the elephants, up to 120 m from the signal source. Precise distances between sensors was measured with a differential GPS. Some trials were also conducted using microphone/geophone pairs at 30- and 120-m distances to compare attenuation in the air in relation to attenuation in the ground. Recordings were made with a four channel data acquisition system, processing signals simultaneously from the geophone string and the microphone/geophone pairs at the near and remote locations. Previous studies indicated that elephant vocalizations and locomotion produce Rayleigh waves, a type of ground surface wave. In this study, the long-range seismic characteristics of the signal sources is described. The propagation of elephant vocalizations in the air and ground is quantified at a range of distances up to 120 m and the rates of signal attenuation within each of the two media are compared.

Effect of Prenatal Stress on Opioid Component of Exploration in Different Experimental Situations

Prenatal stress interferes with the expression of opioid systems in rats. The present study determined the effect of prenatal stress on the opioid-influenced component of exploratory behavior, defined as the difference between the behavior of vehicle-treated and naloxone-treated rats, in three novel situations previously shown to cause different degrees of arousal. Pregnant rats were stressed three times weekly on a random basis by noise and flashing lights. Experiments were performed on 60–70-day-old offspring (male and female) of control and stressed dams. Fifteen minutes after injection of vehicle or naloxone (1 mg/kg), the proportion of time spent in eight different behavioral parameters, including locomotion, rearing, sniffing, hole poking, pivoting, and grooming, was assessed during 4 min of exposure to an open field, either with or without prior exposure to a hole box. The magnitude of the depressant effect of naloxone on exploration depended on the nature of the environment, previous experience of the animal in another situation, and the parameter of exploration assessed. The opioid-influenced component of locomotion and rearing was significantly reduced by prenatal stress, particularly in female rats. Further studies using a cross-fostering design are needed to assess the relative contributions of pre- and postnatal factors to the reduction of opioid activity in prenatally stressed rats. More specific opioid antagonists could be used to determine the nature of the opioid receptors involved.

Orphan neuropeptide NocII, a putative pronociceptin maturation product, stimulates locomotion in mice.

NocII is a heptadecapeptide whose sequence lies immediately downstream of nociceptin, the newly discovered natural agonist of the ORL1 receptor, in pronociceptin, nociceptin's precursor polypeptide. Since the sequence of NocII is framed by putative convertase excision sites and it totally conserved across murine and human species, we have sought to determine whether this orphan neuropeptide might by physiologically significant, i.e. endowed with central biological activity in vivo. Intracerebroventricular administration of 10 and 100 ng of NocII increased locomotion in mice. However, unlike nociceptin, which stimulates both the horizontal and vertical (rearing) components of locomotion, NocII affected only the horizontal component. The motor stimulant action of NocII appears to depend largely on dopamine transmission since it is totally reversed by the D1 or the D2 dopamine receptor antagonists SCH 23390 and haloperidol. NocII does not modify the number of explored holes in the hole board test, indicating that, unlike nociceptin, the orphan peptide does not affect exploratory behavior in mice.

Nociceptin stimulates locomotion and exploratory behaviour in mice

The recently characterized heptadecapeptide nociceptin, the endogenous agonist of the orphan opioid receptor-like 1 (ORL 1 receptor), has been tested for its effects on locomotion and exploratory behaviour in mice. I.c.v. administration of as little as 10 ng of nociceptin/animal stimulated locomotor activity. This effect was dose-dependent, increasing in intensity up to 100 ng and in duration for doses in the range of 1000–10 000 ng. The stimulation of horizontal locomotion elicited by 100 ng nociceptin was accompanied by a stimulation of the vertical component of locomotion. These effects were not reversed by high doses (1.5 and 4.5 mg/kg s.c.) of the opioid receptor antagonist naloxone. Increasing doses of the dopamine D 2 receptor antagonist haloperidol (0.1–0.5 mg/kg i.p.) as well as of the dopamine D 1 receptor antagonist SCH 23390 [ R(+)-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1 H-3-benzazepine hydrochloride] (0.0075–0.03 mg/kg s.c.) reversed this effect, suggesting that nociceptin exerts its motor-stimulant actions by increasing central dopaminergic transmission. Nociceptin was also found to increase the number of head dips in the hole-board test, indicating that the peptide stimulates exploratory behaviour.

A complete skeleton of the giant South American primate Protopithecus.

A complete skeleton of a large-bodied New World monkey has been found in Pleistocene cave deposits in the Brazilian state of Bahia. It demonstrates an unprecedented combination of body size, locomotor and cranial morphology. Skeletal features indicate an animal of approximately 25 kg, more than twice the mass of any living South American monkey. We refer the specimen to Protopithecus brasiliensis Lund, 1838, a large Pleistocene primate originally represented by only a proximal femur and distal humerus. The skeleton resembles species of two distinct New World monkey lineages. The cranium is modified for an enlarged vocal sac typical of living howler monkeys, and the postcranium includes suspensory and brachiating components of locomotion as seen in living spider and woolly spider monkeys. This skeleton confirms that adaptive diversity in neotropical primates was greater in the recent past, and that current interpretations of how their distinctive adaptations evolved should be revised.

Recovery of function after spinal cord hemisection in newborn and adult rats: Differential effects on reflex and locomotor function

It is often assumed that the response of the immature nervous system to injury is more robust and exhibits greater anatomical reorganization and greater recovery of function than in the adult. In the present experiments the extent of recovery of function after spinal cord injury at birth or at maturity was assessed. We used a series of quantitative tests of motor behavior to measure reflex responses and triggered movements and to examine different components of locomotion. Rats received a midthoracic “over-hemisection” at birth or as adults. The neonatal operates were allowed to mature and the adult operates were allowed to recover. The animals were trained to walk on a treadmill and to cross runways of varying difficulty. The animals were tested for reflex responses and triggered movements, videotaped while crossing the runways, and footprinted while walking on the treadmill. The adult operates had greater deficits in the reflex responses than the neonatal operates. The adult operates lost the contact placing response and had a decreased hopping response in the ipsilateral limb, while these responses were not impaired in the neonatal operates. Although the contact placing response in the neonatal operates was spared, a greater stimulus was necessary to induce the response than in control animals. In contrast, the neonatal operates had greater deficits in locomotion. Footprint analysis revealed that the animals' base of support was significantly greater after the neonatal injury than after the adult injury, and deficits in limb rotation were larger in the neonatal operates than in the adult operates. Both groups crossed the grid with a similar number of steps but the adult operates made significantly more errors with the hindlimb ipsilateral to the lesion than the contralateral one, while the neonatal operates made an equivalent number of errors with both limbs. The neonatal operates took longer to execute the climb test and used a different movement pattern than the adult operates. The neonatal operates had a different locomotor pattern than the adult operates. Despite greater recovery of reflex responses after spinal cord injury at birth, the pattern of locomotion exhibits greater deficits when compared with the same lesion in the adult. Just as the anatomical consequences of injury to the developing nervous system are not uniform, similarly, the behavioral consequences are also not uniform. Spinal cord injury before the mature pattern of locomotion has developed results in a different motor strategy than after injury in the adult. The observation that locomotor patterns and motor strategies differ between newborn and adult operates suggests that the mechanisms underlying the recovery also must differ.

Early neural grafts transiently reduce the behavioral effects of radiation-induced fascia dentata granule cell hypoplasia

X-irradiation of the neonatal rat hippocampus produces a selective hypoplasia of fascia dentata granule cells, locomotor hyperactivity, perseverative movements and deficits in passive avoidance. We previously reported that transplantation of fetal hippocampal tissue into the adult (age= 182 ± 4days) brain produced a partial recovery of these behavioral deficits. Since graft/host interconnections are more prominent when transplants are conducted soon after radiation-induced hippocampal damage, in this study we transplanted hippocampal or cerebral cortex neurons when host rats were33 ± 5days of age (i.e. only 10 days after radiogenic brain damage). Behavioral evaluations were conducted 80 and 182 days after transplantation or surgical control procedures. In the first test series only, selective components of locomotion (e.g. stereotypy and total distance traveled) and perseverative turning (e.g. mean bout length and turning speed topography) were normalized by the hippocampal grafts. Radiation-induced changes in passive avoidance wereless prominent in these studies than in past experiments. Still, transplantation of hippocampal tissue improved performance on this learning task as well. Cerebral cortex grafts did not produce reliable improvements in most behavioral measures. These data suggest that hippocampal grafts placed soon after X-ray induced fascia dentata hypoplasia reduce a broad range of behavioral deficits. However, these benefits are transient and, for the most part, depend on the use of transplant tissues homologous with those damaged.

Sensory Basis and Functional Role of Eye Movements Elicited During Locomotion in the Land Crab Cardisoma Guanhumi

ABSTRACT Eye movements in the horizontal plane and the rotatory component of body movement have been continuously recorded in land crabs, Cardisoma guanhumi Latreille, walking freely in an arena. The results show that the eyes compensate for locomotor turns by moving in the opposite direction to the body, thus reducing the image motion of surrounding objects on the retina. Gains often approach unity, so that stabilization of the rotatory component of self-generated image motion is good. Of the three compensatory eye reflexes that could contribute to these responses, optokinetic responses play a major role, since the gain of the responses of freely walking blinded crabs was about half that of crabs that could see. Since blinded crabs held above a ball moved their eyes whenever they rotated the ball about a vertical axis (i.e. turned), a significant role for leg proprioceptor-driven eye movements is also presumed. It is unclear whether vestibular nystagmus, driven by the statocysts, also has a role to play. In contrast to the high-gain compensatory responses that accompany turns, the translatory component of locomotion elicits compensatory eye movements only under the most favourable circumstances, when the crab walks along a runway facing a set of stripes. Even then, the responses are of very low gain (0.02-0.09). Amongst several possible factors, this is partly because lateral ommatidia, which drive the optokinetic responses, will face the poles of the flow field during sideways walking, and partly because stationary contrasts (as occur at the poles of the flow field) reduce the gain of optokinetic responses. It is argued that, by compensating for turns but not translatory locomotor movements, crabs effectively separate the rotatory from the translatory components of the visual flow field around them. Since only the former can be used in course control, while only the latter provides information on ground speed and the three-dimensional layout of the environment, such a separation makes good functional sense.

Role of delta opioid receptors in the effects of inhibitors of enkephalin-degrading peptidases on the horizontal and vertical components of locomotion in mice

In the present study we report the effects of inhibitors of enkephalin-degrading peptidases on spontaneous locomotion in mice and the involvement of delta opioid receptors in these effects. Animals received intracerebroventricularly (i.c.v.) or intravenously (i.v.) enkephalinase inhibitors (thiorphan and acetorphan), aminopeptidase inhibitors (bestatin and carbaphethiol) or mixed peptidase inhibitors (kelatorphan). The i.c.v. co-administration of bestatin and thiorphan (50 μg + 50 μg) induced an increase in both the horizontal and vertical components of locomotion. A similar pattern was observed after the i.c.v. administration of kelatorphan (8.5–50 μg) or the i.v. co-administration of acetorphan and carbaphethiol (5 mg/kg + 10 mg/kg). The opiate antagonist naltrexone (1 mg/kg, s.c.) failed to reverse the excitolocomotor effects of kelatorphan or of bestatin and thiorphan and antagonized only partially the effects of acetorphan and carbaphethiol. Naloxone (2 mg/kg–10 mg/kg, s.c.) partially reversed the increase in locomotion elicited by bestatin and thiorphan. The pretreatment with the delta opioid antagonists ICI 154,129 (20 μg, i.c.v.) or ICI 174,864 (2–4 μg, i.c.v.) strongly decreased the effects of all the peptidase inhibitors we tested. These results suggest that endogenous enkephalins may control via delta opioid receptors the horizontal and vertical components of locomotor activity in mice.

A study of locomotor behavior in a captive colony of red-bellied lemurs (Eulemur rubriventer).

The considerable diversity of locomotor behavior within the suborder Prosimii largely is due to differences in locomotion between families. Within families, locomotion is relatively homogeneous, although some species, such as Otolemur crassicaudatus among the galagids and Hapalemur simus and Lepilemur spp. among the lemurids, differ from other species in their family. This paper describes the locomotion of a captive colony of red-bellied lemurs, Eulemur rubriventer (following the classification of Simons and Rumpler [1988] who place all species of Lemur other than Lemur catta in the genus Eulemur), another species whose movements differ markedly from other members of its family, the Lemuridae. Features that distinguish the locomotion of E. rubriventer from other lemurids are the high frequency of leaping, low frequency of climbing and suspension, and the use of head-downward vertical climbing in this species. Leaping is the most common form of locomotion in E. rubriventer. Horizontal, rather than vertical supports, are preferred during leaping. Although the frequency of climbing in this study is relatively low, the large brachioradialis flange, robust hallux, and claw-like nails of E. rubriventer suggest that clinging and climbing on large diameter vertical supports (lacking in the enclosures used in this study) may be an important component of locomotion in wild E. rubriventer and may reflect a gummivorous or insectivorous dietary adaptation. While the locomotion of E. rubriventer differs from all prosimians yet studied, the general pattern of locomotor behavior seen in this species is most similar to other species of the family Lemuridae.

MU and delta opioid receptors control differently the horizontal and vertical components of locomotor activity in mice

The present study investigated the role of mu and delta opioid receptors in the control of the horizontal and vertical components of locomotion. Mice received intracerebroventricularly (i.c.v.) enkephalin analogs specific for either the mu or delta opioid receptors. The administration of the specific mu agonist [D-Ala 2-NMePhe 4-Gly 5(ol)] enkephalin (DAGO) induced a dose-dependent increase in horizontal activity and a decrease in vertical activity. The specific delta agonist [D-Pen 2, D-Pen 5] enkephalin (DPDPE) increased both components of motor activity. The opiate antagonist naltrexone reversed the effects of DAGO, but did not influence the effects of DPDPE on motor activity. The pretreatment with the delta opiate antagonist ICl 154, 129 completely reversed the effects of DPDPE on locomotion but antagonized only partially the effects of DAGO on locomotion. These results indicate that the two components of locomotor activity — horizontal and vertical activity — are modulated differently by the stimulation of mu or delta opioid receptors.