Anatomy of the bony pelvis in parapithecid primates

Four partial innominate bones, attributed to the parapithecid primates Parapithecus grangeri and Apidium phiomense, have recently been recovered from Oligocene deposits in the Fayum of Egypt. These fossils provide the first documentation of pelvic morphology for early anthropoids. In pelvic anatomy, parapithecids show definite similarities to higher primates rather than to prosimians, but cannot be clearly allied with any one extant group. Functionally, the fossils indicate quadrupedal or leaping habits rather than suspensory or bipedal behaviors.     

Dental formulae and dental eruption patterns in Parapithecidae (Primates, Anthropoidea)

The eruption sequence for the lower teeth of Apidium phiomense based on 18 juvenile specimens is dP3, dP4, M1, M2, P2, P4, (P3, M3), C. Only five specimens of Parapithecus grangeri show developing lower teeth. P2, M1, and M2 all erupted before P3 and P4; C and M3 were the last cheek teeth to erupt. Late eruption of the lower canines in parapithecids is a possible shared derived resemblance linking these species with Anthropoidea and Adapidae and distinguishing both from Omomyidae, Tarsiidae, and tooth-combed lemurs. Late eruption of M3 in parapithecids is a shared derived resemblance with Anthropoidea alone. The lower dental formula of Apidium phiomense is confirmed as 2 X 1 X 3 X 3 by additional specimens which show the incisors. Based in part on tooth socket counts, the deciduous lower dental formula was 2 X 1 X 3. New specimens of Parapithecus grangeri now demonstrate an adult mandibular dental formula of 0 X 1 X 3 X 3 (not 2 X 1 X 3 X 3 as previously thought) and a juvenile formula of 1 X 1 X 3. The number of incisors possessed by Parapithecus fraasi is again open to debate. Material is insufficient to judge whether this species had a pair of incisors in each lower jaw quadrant, by analogy with Apidium, or had undergone reduction to just one incisor. In any event, the presence of two incisors in another parapithecid Apidium shows anterior tooth reduction of Parapithecus grangeri occurred independent of, and should not be considered a shared derived similarity with, Tarsiidae, as was once thought.     

The effects of nutritional polyunsaturated fatty acids on locomotor activity in spontaneously hypertensive rats

The present study investigated the effects of nutritional omega-3 polyunsaturated fatty acids on locomotor activity in spontaneously hypertensive rats (SHRs), which are used as an animal model of attention-deficit/hyperactivity disorder (ADHD). For 6 weeks, two groups of randomly assigned SHRs received food either enriched with or deficient in omega-3 fatty acids (based on the American Institute of Nutrition—93 G/AIN93G). Using an open field, locomotor activity was subsequently assessed for 6 days. A marked difference in locomotor activity as assessed by the distance travelled in the open field was found between the two groups of rats. In comparison with rats fed with omega-3 fatty acid-enriched food, the animals on the omega-3 fatty acid-deficient diet showed a significantly higher locomotor activity. The present findings demonstrated that nutritional enrichment with omega-3 fatty acids was associated with reduced motor activity in an established animal model of ADHD and support the notion that omega-3 polyunsaturated fatty acids may play a role in the pathophysiology of ADHD.     

Locomotor adaptations within the Cercopithecus Genus: a multivariate approach.

Multivariate analysis as a technique for investigating locomotor differentiation among primates has proven its power and usefulness in many studies on various skeletal dimensions. In these analyses primate genera were distributed and sometimes clustered in a manner that was interpretable based on current knowledge of gross locomotor differences. In an effort to advance our understanding of arboreality and terrestriality in primates, the present research involves a careful look for the most subtle morphological differences in locomotor behavior. It is believed that by looking at such subtle shape differences an understanding of what it means morphologically for a primate to be either more or less arboreal may be achieved. The species within the primate genus Cercopithecus were analyzed. This genus includes species which may be placed along a habitat (ground-living to tree-dwelling) or activity spectrum. The different habitats or activity patterns clearly require slight variations in patterns of movement, which in turn may require subtle structural adaptations. Multivariate analyses of 67 postcranial variables on seven species within the genus allowed detection of slight degrees of morphological variation. However, when morphological differences are small, size variance among specimens may take on an inflated importance. A substantial amount of work was devoted to finding the least biased method of removing size variance from the variables while incorporating a discrete size variable into the study. Using these transformed skeletal variables, interspecific groupings were discovered. Much of this infrastructure is then related to differing locomotor behavior and provides an insight into the fine structure of primate locomotor adaptation in an arboreal habitat.     

Aβ42转基因AD果蝇的构建及在药物筛选中的运用

阿尔茨海默病（Alzheimer’s disease,AD）是一种以β-淀粉样蛋白的形成和沉积为主要特征的神经退行性疾病,Aβ42被认为在AD的发病过程中起着重要的作用。果蝇是一种遗传操作简便的模式动物,利用果蝇中经典的Gal4／UAS系统,作者构建了在中枢神经系统中全神经元或运动神经元表达单拷贝或双拷贝AB42的转基因AD果蝇,并检验转基因果蝇在AD治疗药物筛选中的作用。结果显示,转基因AD果蝇寿命明显缩短且运动能力降低,而使用AD临床治疗药物安理申后,可延长AD果蝇寿命,改善AID果蝇的运动障碍。进一步的研究显示,δ阿片受体拮抗剂naltrindole给药后,也能缓解这些症状。该研究为AD治疗药物的初筛提供了一个经济便捷的工具。     

Circadian Rhythms of Locomotor Activity in Lycosa tarentula (Araneae, Lycosidae) and the Pathways of Ocular Entrainment

Lycosa tarentula is a ground-living spider that inhabits a burrow where it awaits the appearance of prey or conspecifics. In this study, circadian rhythms of locomotor activity were examined as well as the ocular pathway of entrainment. Thirty-three adult virgin females were examined under constant darkness (DD); all of them exhibited robust circadian rhythms of locomotor activity with a period averaging 24.1h. Fourteen of these spiders were studied afterwards under an LD 12:12 cycle; they usually entrained to in the first or second day, even when the light intensity was as low as 1 lx. During the LD cycle, locomotor activity was generally restrained to the darkness phase, although several animals showed a small amount of diurnal activity. Ten males were also examined under LD; they were also nocturnal, but were much more active than the females. Seven females were examined under constant light (LL); under this they became arrhythmic. Except for the anterior median eyes (OMAs), all the eyes were capable of entraining the locomotor activity to an LD cycle. These results demonstrate that under laboratory conditions and low light intensities locomotor activity of Lycosa tarentula is circadian and in accordance with Aschoff's 'rule'. Only OMAs are unable to entrain the rhythm; the possible localization of circadian clock is therefore discussed.     

Characterization of the locomotor depression produced by an A2-selective adenosine agonist

Adenosine analogs, such as N6-cyclohexyladenosine (CHA) that are selective for A1-adenosine receptors, and analogs, such as 5'-N-ethylcarboxamidoadenosine (NECA) that are active at both A1 and A2 receptors, cause a profound depression of locomotor activity in mice via a central mechanism. The depression is effectively reversed by non-selective adenosine antagonists such as theophylline. We report that 2-([2-aminoethylamino) carbonylethylphenylethylamino]-5'-N-ethylcarboxamidoadenosine (APEC), an amine derivative of the A2-selective agonist, CGS21680, is a potent locomotor depressant in mice. The in vivo pharmacology is consistent with A2-selectivity at a central site of action. Two parameters indicative of locomotor activity, horizontal activity and total distance travelled, were measured using a computerized activity monitor. From dose-response curves it was found that APEC (ED50 16 micrograms/kg) is more potent than CHA (ED50 60 micrograms/kg) and less potent than NECA (ED50 2 micrograms/kg). The locomotor depression by APEC was reversible by theophylline, but not by the A1-selective antagonists 8-cyclopentyltheophylline (CPT) and 8-cyclopentyl-1, 3-dipropyl-2-thioxanthine, nor by the peripheral antagonists 8-p-sulfophenyltheophylline (8-PST) and 1,3-dipropyl-8-p-sulfophenylxanthine. The locomotor activity depression elicited by NECA and CHA was reversed by A1-selective antagonists. These results suggest that the effects of APEC are due to stimulation of A2 adenosine receptors in the brain.     

Comparison of instantaneous and locomotor bout sampling methods: a case study of adult male chimpanzee locomotor behavior and substrate use.

Currently two methods, instantaneous and locomotor bout sampling, are used most commonly in studies of locomotor behavior. To date, no study has addressed how comparable the results of the two methods are. This paper considers whether different sampling methods of locomotor behavior produce different results. Continuous locomotor bout and instantaneous sampling were carried out simultaneously on each focal animal during a seven month study of chimpanzee positional behavior in the Tai Forest of the Ivory Coast. Results provide two independent sets of data which describe the same events. Results indicate that as locomotor bouts are frequently presented (the percentage of bouts spent in an activity), they overrepresent the frequencies of activities that occur relatively often, but for short distances, and underrepresent activities that have a relatively large mean distance per bout. However, when bouts are weighted with distance, as originally defined by Fleagle (1976b), there are no significant differences in the results obtained by the two methods. Both provide similar results for the frequencies of locomotor activities, frequency of substrate use, and the relationship between substrate and locomotor activity. The advantage of instantaneous sampling is that because it is done at regular intervals, it can easily be carried out in conjunction with sampling other behavioral and ecological data. The advantages of locomotor bout sampling are that it permits the sampling of rare or brief locomotor events and allows for an analysis of sequences of locomotor activities. This paper demonstrates that the two methods can be conducted simultaneously and thus provide the richest return from which the effect of environment and morphology on locomotion can be addressed.     

Circadian Rhythms of Locomotor Activity in Lycosa tarentula (Araneae,Lycosidae) and the Pathways of Ocular Entrainment

Lycosa tarentula is a ground-living spider that inhabits a burrow where it awaits the appearance of prey or conspecifics. In this study, circadian rhythms of locomotor activity were examined as well as the ocular pathway of entrainment. Thirty-three adult virgin females were examined under constant darkness (DD); all of them exhibited robust circadian rhythms of locomotor activity with a period averaging 24.1h. Fourteen of these spiders were studied afterwards under an LD 12:12 cycle; they usually entrained to in the first or second day, even when the light intensity was as low as 1 lx. During the LD cycle, locomotor activity was generally restrained to the darkness phase, although several animals showed a small amount of diurnal activity. Ten males were also examined under LD; they were also nocturnal, but were much more active than the females. Seven females were examined under constant light (LL); under this they became arrhythmic. Except for the anterior median eyes (OMAs), all the eyes were capable of entraining the locomotor activity to an LD cycle. These results demonstrate that under laboratory conditions and low light intensities locomotor activity of Lycosa tarentula is circadian and in accordance with Aschoff's 'rule'. Only OMAs are unable to entrain the rhythm; the possible localization of circadian clock is therefore discussed.     

Locomotor performance and social dominance in male Anolis cristatellus

The proximal mechanisms determining social dominance are not well understood. We used the highly territorial lizard A. cristatellus to test two main hypotheses: (1) that male social dominance is associated with locomotor abilities; (2) that locomotor abilities (maximal performance), as measured in the laboratory, are correlated with behaviour in the field. In the field, we recorded locomotor behaviours and assertion displays, then characterized microhabitat use and thermal relations. In the laboratory, we measured maximum sprint running speed, endurance and morphometric characters, and assessed dominance by pairing males of similar body size in an experimental arena. In 72 of 77 interactions, one lizard (the ‘winner’) was unequivocally determined to be dominant over the other (the ‘loser’). Winners performed more assertion displays than losers before capture and also had higher endurance in laboratory tests. Although contestants were matched for snout-vent length, winners had significantly deeper and wider heads. However, we found no significant differences in field locomotor behaviours, perch or thermal characteristics, head length, or maximal sprint speed. Our findings support those of previous studies, and extend them in several ways. This is the first demonstration that assertion displays in the field are related to both locomotor performance and laboratory-assessed social dominance. Locomotor performance may directly affect social dominance by allowing some males to perform better in dyadic interactions. Alternatively, both locomotor performance and social dominance may be linked to a common underlying mechanism, such as variation in hormone levels, which are known to affect aggression, locomotor performance and morphology.     

Evidence at hand: Diversity, functional implications, and locomotor prediction in intrinsic hand proportions of diprotodontian marsupials

Knowledge about the diversity, locomotor adaptations, and evolution of the marsupial forelimb is limited, resulting in an underrepresentation of marsupials in comparative anatomical literature on mammalian forelimb anatomy. This study investigated hand proportions in the diverse marsupial order Diprotodontia. Fifty-two measurements of 95 specimens representing 47 species, as well as 6 non-diprotodontian specimens, were explored using principal components analysis (PCA). Bootstrapping was used to assess the reliability of the loadings. Phylogenetically independent contrasts and phylogenetic ANOVA were used to test for correlation with size and functional adaptation of forelimbs for locomotor habit, scored as arboreal vs. terrestrial. Analysis of first principal component (PC1) scores revealed significant differences between arboreal and terrestrial species, and was related to relative slenderness of their phalangeal elements. Both locomotor groups displayed allometry along PC1 scores, but with different intercepts such that PC1 discriminated between the two locomotor habits almost completely. PC2 separated some higher-level clades and burrowing species. Analysis of locomotor predictors commonly applied by palaeontologists indicates that ratios between proximal and intermediate phalanges were unsuitable as predictors of arboreality/terrestriality, but the phalangeal index was more effective. From PCA results, a phalangeal slenderness ratio was developed which proved to be a useful discriminator, suggesting that a single unallocated phalanx can be used for an impression of locomotor mode in fossils. Most Diprotodontia are laterally paraxonic or ectaxonic, with the exception of digging species whose hands are medially paraxonic. Our results complement those of studies on placental mammals, suggesting that the demands of arboreality, terrestriality, or frequent digging on intrinsic hand proportions are met with similar anatomical adaptations in marsupials.     

Plasticity of connections underlying locomotor recovery after central and/or peripheral lesions in the adult mammals

This review discusses some aspects of plasticity of connections after spinal injury in adult animal models as a basis for functional recovery of locomotion. After reviewing some pitfalls that must be avoided when claiming functional recovery and the importance of a conceptual framework for the control of locomotion, locomotor recovery after spinal lesions, mainly in cats, is summarized. It is concluded that recovery is partly due to plastic changes within the existing spinal locomotor networks. Locomotor training appears to change the excitability of simple reflex pathways as well as more complex circuitry. The spinal cord possesses an intrinsic capacity to adapt to lesions of central tracts or peripheral nerves but, as a rule, adaptation to lesions entails changes at both spinal and supraspinal levels. A brief summary of the spinal capacity of the rat, mouse and human to express spinal locomotor patterns is given, indicating that the concepts derived mainly from work in the cat extend to other adult mammals. It is hoped that some of the issues presented will help to evaluate how plasticity of existing connections may combine with and potentiate treatments designed to promote regeneration to optimize remaining motor functions.     

Ecomorphological specialization leads to loss of evolvability in primate limbs*

Primate limb morphology is often described as either generalized, that is, suited to a range of locomotor and positional behaviors, or specialized for unique locomotor behaviors such as brachiation or bipedalism. The evolution of highly specialized limb morphology may result in loss of evolvability, that is, in a decreased capacity of the locomotor skeleton to evolve in response to selection towards alternative ecomorphological niches. Using evolutionary simulations, I show that the highly specialized limb anatomy of hominoids is associated with a significant loss of evolvability, defined as the number of generations to reach alternative adaptive peaks, and in parallel an increased risk of extinction, particularly in simulated evolution toward generalized quadrupedal limb proportions. Loss of evolvability in apes and humans correlates with three factors: (1) decreased correlation among limb bone lengths (i.e., integration), which slows the rate of change along lines of least evolutionary resistance; (2) limb specialization, which places apes and humans in relatively remote areas of morphospace; and (3) increased skeletal size as a proxy for body size. Thus, locomotor over-specialization can lead to evolutionary dead-ends that significantly increase the probability of hominoid populations going extinct before evolving new adaptive morphologies.     

Biomechanics and allometric scaling in primate locomotion and morphology

Body size has a dominant influence on locomotor performance and the morphology of the locomotor apparatus. In locomotion under the influence of gravity, body mass acts as weight force and is a mechanical variable. Accordingly, the application of biomechanical principles and methods allows a functional understanding of scaling effects in locomotion. This is demonstrated here using leaping primates as an example. With increasing body size, the decreasing ratio of muscle force available for acceleration during takeoff to the body mass that has to be accelerated dictates both the movement pattern and the proportions of the hindlimbs. In an arm-swinging movement, the long, heavy arms of the large-bodied leapers are effectively used to gain additional momentum. A new perspective on decreasing size identifies the absolutely small acceleration distance and time available for propulsion as factors limiting leaping distance and extensively determining locomotor behavior and body proportions. As the mechanical constraints differ according to body size for a given mode of locomotion, a typological approach to morphology in relation to locomotor category is ruled out. Across locomotor categories, dynamic similarity (sensu Alexander) can be expected if the propulsive mechanisms as well as the selective pressures acting upon locomotion are the same.     

A note on the effect of isolation during testing and length of previous confinement on locomotor behaviour during open-field test in dairy calves

This study investigated firstly if confined calves perform more locomotor behaviour when open-field tested in pairs than when tested individually, and secondly if length of confinement affects the build-up of motivation to perform locomotor behaviour. In the first experiment,14 calves were open-field tested on two successive days either individually or as a pair. Calves walked more and performed more locomotor play when tested in pairs, suggesting that it may be appropriate to avoid isolation when aiming to measure the effects of confinement on locomotor behaviour. In the second experiment, in each of three successive weeks, 24 calves had access to an exercise arena for 45 min daily on three successive days either: (i) the first 3 days, (ii) the third, fourth and fifth day, or (iii) the fourth, fifth and sixth day. On the seventh day the calves were released into the arena for 10 min (open-field test). All calves received all three treatments in a Latin square design. Calves performed more locomotor play, and they trotted more after 3 days without access to the arena than after 1 or 0 days, suggesting that in calves the motivation to perform locomotor play and trotting increases with length of confinement.     

A sequential analysis of female aggression in a group of lesser galagos (Galago senegalensis)

A sequential analysis of behaviors preceding agonistic interactions between female lesser galagos demonstrated that aggression usually follows locomotor or interactive, as opposed to solitary, behavior. Leaping or leaving a nest box followed by mutual staring is a frequent component preceding both chases and displacements. The probability of predicting an agonistic interaction is improved when more behaviors are examined in sequence, although one cannot predict aggression with certainty due to the variability of preceding sequences. Mutual staring is suggested to be an evolutionary precursor to elaborate visual threat signals.     

Respective Role of the Axialand Appendicular Systems in Relation to the Transition to Limblessness

In lower quadrupedal vertebrates locomotor efficiency seems to result from the associate movements of the axial and appendicular systems, which are totally independent in structure and embryological origin. The curvature of the trunk, produced by a standing wave, magnifies the propulsive action of the limbs. In intermediate forms, the association of an elongate trunk with limbs reduced in size brings about functional consequences which may be noticeably diverse according to the degree of trunk elongation and limb reduction. According to environmental constraints, animals search for better locomotor efficiency, which implies the maintenance or breakage of this association of both locomotor systems. In some cases, limb action on the ground is added to the axial wave action through a perfect mutual adjustment of rhythmic activity, until mechanical inefficiency of the limbs is reached by possible loss of contact with the ground. In other cases, the limbs dragged on the ground during the stance phase act against the axial action or, on the contrary, are inhibited by the axial system. A review of available data tries to contribute to an understanding of the respective roles of both systems in the transition to limblessness.     

Effects of dopaminergic and cholinergic interactions on rat behavior.

The present work studied the effects of dopaminergic and muscarinic receptor agonists and antagonists on rat locomotor activity and catalepsy. Results showed that carbachol at the highest dose used (10 mg/kg, p.o.) decreased and pimozide at the dose used abolished locomotor activity. Atropine at a low dose (1 mg/kg, p.o.) increased and at a high dose decreased this parameter. Mazindol at a high dose also increased locomotor activity. A significant and dose-dependent increase in the time on the bar was observed in animals treated with carbachol or pimozide as compared to controls. The increase observed with pimozide was greater than 60 s. Effects of carbachol on locomotor activity were observed already after the first drug exposure, but the increased time on bar produced by this drug in the test of catalepsy was observed only after repeated exposure (7th day). The effect of the highest dose (10 mg/kg, p.o.) of atropine (decreased activity) as related to the lowest one was evident at the 7th day, but the increased locomotor activity seen at the low dose was detected already at the first day. There was a predominance of the effect of pimozide on the open field as well as on catalepsy after its association with each one of the three doses of carbachol. The association of atropine and mazindol did not seem to alter locomotor activity and catalepsy as related to each drug alone. Our results indicate that interactions between dopaminergic and cholinergic systems play an important role on behavior and motor functions.     

Determinants of musculoskeletal frailty and the risk of falls in old age

Neuromuscular parameters that describe locomotion are indispensable variables for the diagnosis and treatment of frailty, fall risk and osteoporosis. A scientifically-based standardized locomotor assessment should be an essential part of medical examinations in research and clinical practice. There has been no previous consensus regarding which test procedures should be included in a locomotor assessment. The goal of this article is to provide a rationale for the selection of appropriate locomotor tests in a comprehensive locomotor assessment for elderly patients. We propose that a locomotor assessment should comprise the parameters that have been proven predictive for both falls and impending disability. The parameters should be measured in the standard units of physics. Therefore, we propose the following tests for a standardized locomotor assessment: (1) Self-selected gait velocity as the single best measure of general locomotor status and a good predictor of age-related adverse events; (2) Chair rise test (timed 5 chair rises) which measures power on vertical movement and the hip surrounding muscles as the most important neuromuscular risk factor for falls and fall-related fractures; (3) Tandem standing and tandem walking to measure postural capacity (balance) to the side; (4) Timed up and go test as a global screening procedure; (5) Clinical gait analysis with special focus on regularity; and (6) At least on a research level, movement must be measured referring to the terms of physics by mechanography. Mechanography (Leonardo force plate system, Novotec Pforzheim, Germany) records the time course of ground reaction forces, velocity of the vertical movements of the center of mass and power during unrestricted physiological movements. In the mechanogram the eccentric and concentric phases of movements can be differentiated and the storage of energy in the elastic elements of the body can be examined. The kinetics of human movement is explained by mechanograms of a two-legged jump. The ground reaction forces resulting from a jump down from a height of 0,46 m are demonstrated as a performance that is representative for human coordination. One goal of this text is to underline the insights that arise if the rules of physics are applied to human movement. A deeper understanding enables us to create more effective treatments for disorders of the muscle-bone unit. Bringing physics and cybernetics into the field of osteoporosis is a great heritage of Harold Frost.