Animal Posture Research Articles

A brief note on the validation of a system for recording lying behaviour in dairy cows

The duration and frequency of lying behaviour and the time spent standing are behavioural indicators of cow comfort. The objective of this study was to validate a robustly designed datalogger (DL) for recording standing and lying behaviour of cows at pasture. The datalogger consists of an internal electric circuit, which records voltage (V) at a set interval. The circuit is inactivated (0 V) when an animal stands and reactivated (2.5 V) when the animal lies. Thirteen DL and 39 cows were used over 3 days. Dataloggers were attached to cows’ right hind leg during morning milking. Each DL was programmed to have a logging interval of 5 min. Human observers simultaneously recorded animal posture. Data from DL was adjusted by converting lying bouts of less than 10 min duration to standing behaviour. Results from direct observations were then compared with raw and adjusted data from DL using Cohen's Kappa and Spearman correlations, and an index of concordance for standing, lying and both sets of behaviour was calculated. Kappa and correlation results were higher after adjusting DL data than before ( P < 0.001), suggesting that adjusting data in this fashion improves agreement between direct observation and DL data. The high correlation coefficients between data collected by human observers and data collected by the dataloggers, in addition to high κ-values indicate that the dataloggers are an excellent alternative to direct behavioural observations of standing and lying behaviours of dairy cows at pasture.

Motor correlates of models of secondary bilateral synchrony and multiple epileptic foci

Bilateral synchronous epileptiform discharges registered in patients with partial epilepsies may be generated by different pathophysiological mechanisms. Differentiation between underlying mechanisms is often crucial for correct diagnosis and adequate treatment in clinical epileptology. The aim of this study was to model in rats two possible mechanisms--secondary bilateral sychrony and interaction between multiple epilepic foci. Furthermore, to describe in detail semiology, laterality and differences in motor phenomena. Secondary bilateral synchrony was modeled by unilateral topical application of bicuculline methiodide (BMI) over the sensorimotor cortex. Bilateral symmetric application of BMI was used as a model of multiple epileptic foci. Electrographic and behavioural phenomena were recorded for 1h following the application of BMI. Electroencephalogram in both groups was characterized by presence of bilateral synchronous discharges. Myoclonic and clonic seizures involving forelimb and head muscles represented the most common motor seizure pattern in both groups. Significant differences were found in the laterality of motor phenomena. Motor seizures in unilateral foci always started in the contralateral limbs whereas symmetrical foci exhibited bilateral independent onset of convulsions. Similar lateralization was observed in interictal motor phenomena (myoclonic jerks). An important influence of posture on epileptic motor phenomena was demonstrated. Active or passive changes in animal posture (verticalization to bipedal posture) caused conversion from unilateral myoclonic jerks or clonic seizures to bilaterally synchronous (generalized) motor phenomena in both groups.

A novel concept of Fe-mineral-based magnetoreception: histological and physicochemical data from the upper beak of homing pigeons

Animals make use of the Earth's magnetic field for navigation and regulation of vegetative functions; however, the anatomical and physiological basis for the magnetic sense has not been elucidated yet. Our recent results from histology and X-ray analyses support the hypothesis that delicate iron-containing structures in the skin of the upper beak of homing pigeons might serve as a biological magnetometer. Histology has revealed various iron sites within dendrites of the trigeminal nerve, their arrangement along strands of axons, the existence of three dendritic fields in each side of the beak with specific 3D-orientations, and the bilateral symmetry of the whole system. Element mapping by micro-synchrotron X-ray fluorescence analysis has shown the distribution of iron and its quantities. Micro-synchrotron X-ray absorption near-edge-structure spectroscopy has allowed us to unambiguously identify maghemite as the predominating iron mineral (90 vs 10% magnetite). In this paper, we show that iron-based magnetoreception needs the presence of both of these iron minerals, their specific dimensions, shapes, and arrangements in three different subcellular compartments. We suggest that an inherent magnetic enhancement process via an iron-crusted vesicle and the attached chains of iron platelets might be sufficient to account for the sensitivity and specificity required by such a magnetoreceptor. The appropriate alignment between the Earth's magnetic field and the maghemite bands would induce a multiple attraction of the magnetite bullets perpendicular to the membrane, thus, triggering strain-sensitive membrane channels and a primary receptor potential. Due to its 3D architecture and physicochemical nature, the dendritic system should be able to separately sense the three vector components of the Earth's local field, simultaneously-allowing birds to detect their geographic position by the magnetic vector, i.e., amplitude and direction of the local magnetic field, irrespective of the animal's posture or movement and photoreception.

Adaptive significance of death feigning posture as a specialized inducible defence against gape-limited predators

Death feigning is fairly common in a number of taxa, but the adaptive significance of this behaviour is still unclear and has seldom been tested. To date, all proposed hypotheses have assumed that prey manage to escape predation by sending a death-mimicking signal, although death-feigning postures are markedly different from those of dead animals. Moreover, the efficacy of this technique may largely depend on the foraging mode of the predator; death feigning seldom works with sit-and-wait predators that make the decision to attack and consume prey within a very brief time. We examined whether death feigning in the pygmy grasshopper Criotettix japonicus Haan was an inducible defence behaviour against the frog Rana nigromaculata, a sit-and-wait, gape-limited predator. The characteristic posture assumed by the grasshopper during death feigning enlarges its functional body size by stretching each of three body parts (pronotum, hind legs and lateral spines) in three different directions, thereby making it difficult for the predator to swallow the prey. Our result is the first consistent explanation for why death-mimicking animals do not always mimic the posture of dead animals.

Semicircular canal geometry, afferent sensitivity, and animal behavior.

The geometry of the semicircular canals has been used in evolutionary studies to predict the behaviors of extinct animals. These predictions have relied on an assumption that the responses of the canals can be determined from their dimensions, and that an organism's behavior can be determined from these responses. However, the relationship between a canal's sensitivity and its size is not well known. An intraspecies comparison among canal responses in each of three species (cat, squirrel monkey, and pigeon) was undertaken to evaluate various models of canal function and determine how their dimensions may be related to afferent physiology. All models predicted the responses of the cat afferents, but the models performed less well for squirrel monkey and pigeon. Possible causes for this discrepancy include incorrectly assuming that afferent responses accurately represent canal function or errors in current biophysical models of the canals. These findings leave open the question as to how reliably canal anatomy can be used to estimate afferent responses and how closely afferent responses are related to behavior. Other labyrinthine features, such as orientation of the horizontal canal, which is reliably held near earth-horizontal across many species, may be better to use when extrapolating the posture and related behavior of extinct animals from labyrinthine morphology.

Acoustical cues for sound localization by the Mongolian gerbil, Meriones unguiculatus

The present study measured the head-related transfer functions (HRTFs) of the Mongolian gerbil for various sound-source directions, and explored acoustical cues for sound localization that could be available to the animals. The HRTF exhibited spectral notches for frequencies above 25 kHz. The notch frequency varied systematically with source direction, and thereby characterized the source directions well. The frequency dependence of the acoustical axis, the direction for which the HRTF amplitude was maximal, was relatively irregular and inconsistent between ears and animals. The frequency-by-frequency plot of the interaural level difference (ILD) exhibited positive and negative peaks, with maximum values of 30 dB at around 30 kHz. The ILD peak frequency had a relatively irregular spatial distribution, implying a poor sound localization cue. The binaural acoustical axis (the direction with the maximum ILD magnitude) showed relatively orderly clustering around certain frequencies, the pattern being fairly consistent among animals. The interaural time differences (ITDs) were also measured and fell in a +/- 120 micros range. When two different animal postures were compared (i.e., the animal was standing on its hind legs and prone), small but consistent differences were found for the lower rear directions on the HRTF amplitudes, the ILDs, and the ITDs.

Otto Magnus, Rudolf Magnus, physiologist and pharmacologist, 1873–1927, ed. Louis M Schoonhooven Amsterdam, Koninklijke Nederlandse Akademie van Wetenschappen, Dordrecht, Kluwer Academic Publishers, 2002, pp. xii, 350, illus., €57.00 (hardback 90-6984-327-7).

While the rise of the medical sciences in the nineteenth century has been studied quite extensively over the last few decades, the development of modern biomedicine during the twentieth century is still a relatively little researched area. This biography of Rudolf Magnus, whose main contributions to experimental pharmacology and neurophysiology belong to the first quarter of the twentieth century, is therefore a welcome addition to our knowledge. Written by Magnus's son Otto, this book builds on family documents as well as scientific papers and publications. It provides detailed information on Rudolf Magnus's background and upbringing in a prosperous, educated Jewish family in Brunswick, before it continues with the period of his medical studies in Heidelberg. Here Magnus was especially influenced by the physiologist Wilhelm Kuhne, under whose supervision he graduated MD in 1898 with a study on direct blood pressure measurement in the exposed (animal) artery. In the same year he became assistant to Kuhne's son-in-law, the Heidelberg pharmacologist Rudolf Gottlieb. In 1908 Magnus was appointed to a pharmacological professorship at the University of Utrecht, the first such chair in the Netherlands, which he held until his death. Support from the Rockefeller Foundation allowed him to build here a large institute. Rudolf Magnus's work, both in Heidelberg and Utrecht, reflected the then very close connections between physiology and pharmacology, as can be seen from the numerous extracts of his research papers that this biography provides in English translation. Under Gottlieb, Magnus worked experimentally on diuresis and the mode of action of diuretics and digitalis; and he devised his own method for pharmacological tests on the isolated mammalian intestine, which later in Utrecht enabled him and his assistant Joan Willem le Heux to identify the role of choline in producing intestinal movements. From early on Magnus was also engaged in neurophysiological research. This became his main field in the Utrecht institute, where he explored the so-called “righting reflexes”, which control animal posture and which proved to be useful signs for the clinical diagnosis of human neurological conditions. For this research he and his collaborator Adriaan de Kleijn were considered for the award of the Nobel Prize, when Magnus died unexpectedly in 1927. Magnus had also wider cultural interests, as documented by his Heidelberg lectures on Goethe as a scientist, which are summarized with extracts in English translation in a separate chapter of this biography. Perhaps the most interesting aspect that this book brings out, chiefly through presenting Magnus's notes on his experiences at the International Congresses of Physiologists between 1895 and 1923, is his close relationship to British physiology. Magnus admired the experimental skills of John Newport Langley and Charles Scott Sherrington, both of whom he visited for joint research (in 1905 and 1908, respectively), following a period of laboratory work with Edward Albert Schafer in Edinburgh in 1901. The other side to Magnus's enthusiasm for British researchers was his estrangement from his own head of department, Gottlieb, who eventually dismissed him as his assistant with a letter in 1908 (pp. 193f.), shortly before the offer from Utrecht University became known. Magnus's service as a German medical officer in the First World War, during which he performed research on war gases in the Kaiser Wilhelm Institute in Berlin, caused a cooling period for his international relations, so that he was relieved when Sherrington resumed contact after years of silence in 1922. Despite the wealth of interesting and relevant detail that this biography provides, it is not easy reading. Otto Magnus often lets the historical documents and scientific accounts speak for themselves, rather than giving us a continuous narrative of his father's life and achievements. However, readers with a serious interest in the history of twentieth-century physiology and pharmacology, and in the scientific community that promoted these disciplines, will be richly rewarded.

Experimental diagnostic used of laparoscopy in dogs

,The prescnt Study was carried out on 65 dogs in surgery dept.fac. vet. Med .kafr El-Sheikh. Tania University. The results of /aparoscoi(c examination of Ihe alxlominal Cavily provide accurale inspectton of the anatomical relations between the alxlominal organs and differeniia(e between the normnal and abnormal appearanceof these organs Lapnmscopic biopsy of the liver was done under direct inspection of the selected lobe and provides enough tissue size for histopathological examination. from the proceeding results. it can he concluded that the luparoseopy is an accurate non- ineasive technique .for eXamination and biopsy of the abdominal orqans. The changes of the site of the primary port are indicated according to the organ of interest. The chanqes of the animal posture are indicated to enhance inspection the abdominal organs, The complications of diagnostic laparoscopy and biopsy were minimal. ,

Consequences and assessment of human vestibular failure: implications for postural control.

Labyrinthine afferents respond to both angular velocity (semicircular canals) and linear acceleration (otoliths), including gravity. Given their response to gravity, the otoliths are likely to have an important role in the postural functions of the vestibular apparatus. Unilateral vestibular ablation has dramatic effects on posture in many animals, but less so in primates. Nevertheless, bilateral vestibular lesions lead to disabling symptoms in man related to disturbed ocular and postural control and impaired perception of slopes and accelerations. While seimicircular canal function can be assessed through its effects on vestibular ocular reflexes, assessment of otolith function in man has traditionally been much more difficult. Recent definition of a short latency vestibulocollic reflex, activated by sound and appearing to arise from the saccule, shows promise as a new method of non-invasive assessment of otolith function.

Pyramidal-cell plasticity in weakly electric fish: a mechanism for attenuating responses to reafferent electrosensory inputs

Recordings within the posterior eminentia granularis of the weakly electric fish, Apteronotus leptorhynchus, revealed multiple types of proprioceptive units responsive to changes in the position of the animal's trunk and tail. Intracellular labelling showed that the proprioceptor recordings were made from axons that ramify extensively within the EGp. The location of the somata giving rise to these axons is presently unknown. Electroreceptor afferent responses to electric organ discharge amplitude modulations caused by movement of the animal's tail were compared to responses caused by electronically generated AMs of similar amplitude and time course. These did not differ. Electrosensory lateral line lobe pyramidal cells responded significantly less to electric organ discharge amplitude modulations caused by changing the animal's posture as compared to electronically produced AMs, suggesting that central mechanisms attenuate pyramidal cell responses to reafferent electrosensory inputs. Experiments in which the pattern of reafferent input associated with changes in posture was altered revealed that the pyramidal cells learn, over a time course of several minutes, to reject new patterns of input. Both proprioceptive input and descending electrosensory input to the posterior eminentia granularis are involved in generating the observed plastic changes in pyramidal cell responsiveness.

Quantitation of rodent catalepsy by a computer-imaging technique

Catalepsy is usually defined as a behavioral state in which an animal maintains an unnatural posture for an extended period of time. While numerous laboratory models have been developed for assessing catalepsy, a common problem encountered with most procedures is the difficulty in quantitating immobility. Measurement of catalepsy is still frequently subjective in nature. To eliminate this subjectivity, a computer-based technique was developed for quantitating catalepsy in mice and rats as measured on the elevated ring. The system consisted of a videocamera that was focused on either three mice or two rats. Their behavior was recorded during a 5-min session on videotape that was subsequently transmitted to a Macintosh II microcomputer via a Scion Image-Capture 2 board. A modification of the NIH Image 1. 17 public domain program allowed the image of the rat to be transformed to a purely black or white image by assigning pixel values of either 0 or 256. The subsequent captured image was preprocessed in an identical manner and each pixel was subtracted from its corresponding pixel in the previous frame. Thus, changes in animal posture between the two frames can be quantitated. One subtraction cycle (acquisition, bilevel processing, and subtraction) was repeated at an average rate of approximately one per second. To quantitate immobility by image analysis, each frame was subtracted from the previous frame during a 5-min session. The resulting data were sorted according to the magnitude of movement (number of changed pixels) and plotted vs. time. A biphasic plot resulted, showing a clear demarcation between mobility and immobility that could also easily be distinguished from background noise inherent in the video imaging system. Quantitation of the period of immobility in this fashion was found to be in close agreement with that obtained by human observation over a wide range of immobility-inducing drugs.

Intrapleural liquid flow down a gravity-dependent hydraulic pressure gradient.

We studied the vertical movement of 2 mg technetium-labeled albumin injected intrapleurally in 0.5 ml saline (15% of pleural liquid volume) in eight spontaneously breathing anesthetized dogs subject to a sudden change in posture (prone to supine or vice versa). The albumin movements were evaluated through a large field gamma camera placed laterally to the animal and detecting total (AT) and regional activities from two superimposed equal areas (At and Ab, top and bottom, respectively). The At/Ab ratio decreased from 2.1 to 1.3 in four animals up to 20 min from the change in posture and from 0.9 to 0.5 in four more animals studied from 50 to 90 min from turning maneuver. The rate of change in At and Ab was similar in the two groups of animals and unaffected by the acquisition posture. AT decreased by 7.7 and 3.5% for the two groups, respectively, reflecting albumin clearance from the pleural space. The opposite time course of regional activities and the independence of their rate of change of the At/Ab ratio and of the animal posture suggest a top-to-bottom albumin transfer occurring through a bulk flow of liquid estimated at 0.006 ml.kg-1.h-1. The data are consistent with a measured vertical pleural liquid pressure gradient that does not reflect a hydrostatic condition.

The role of the predorsal bundle in head and body movements elicited by electrical stimulation of the superior colliculus in the Mongolian gerbil.

Thirty-two Mongolian gerbils received bilateral chronic implants of stainless steel electrodes in the superior colliculus. The movements elicited by electrical stimulation were recorded on videotape and measured by means of a computer-assisted image analyzing procedure. Ipsiversive body movements were elicited by stimulation of the anterior part of the superior colliculus. Contraversive head and body movements could be elicited by stimulation over the entire superior colliculus. Amplitudes of head and body movements were dependent upon both stimulation parameters (current and train duration) and the animal's posture at stimulus onset. In a second experiment, the predorsal bundle was cut at its decussation by means of a stereotaxic microknife. After such cuts, contraversive turns were either abolished or were replaced by ipsiversive movements. Ipsiversive movements were unaffected by the knife cuts. This experiment provides evidence that the distinct types of movements that can be elicited by collicular stimulation are subserved by anatomically separate output pathways.

Experimental focal cerebral ischaemia in rabbits

A highly reproducible form of experimental embolization of the intracranial arteries is presented in rabbits. The injection of a silver or gold ball into the internal carotid artery caused occlusion predominantly of the middle cerebral artery and/or its branches. At the moment when embolization took place, the characteristic signs of acute cerebral ischaemia occurred in the electroencephalogram, local cerebral blood flow and steady (DC) potentials. Several hours after the ball had been injected the extent of the focal lesions became recognizable on sections stained for myelin. The procedure is simple, rapid, inexpensive and practically always successful. The extent of the lesion may be influenced by the change of both the ball size and the posture of animals. Moreover, the site of occlusion is easily discernible both on radiographs and to the naked eye.

Dysfunction of the midbrain angular complex can accentuate or attenuate circling behaviour in the rat.

The role of the midbrain angular complex (AC) in the execution of motor behaviours was investigated in the rat. In an automated holeboard apparatus bilateral AC electrolesions attenuated exploration and increased locomotor performance of drug-free rats on the first and second test occasions respectively; the latter result may signify a retarding of between-session habituation. Apomorphine also decreased locomotion and almost abolished head dipping and rearing in the holeboard; bilateral AC lesions reinstated locomotion to a normal level without modifying the other behavioural parameters. An electrolesion of one AC did not affect the animal's posture or spontaneous locomotion in the open field, but gave rise to pronounced ipsiversive circling when coupled with systemic administration of apomorphine. In unilaterally 6-hydroxydopamine (6-OHDA) treated rats subcutaneous injection of apomorphine evoked robust contraversive circling. A concomitant lesion of the ipsilateral AC introduced an additional ipsilateral bias to these animals' movements; contraversive circling was initially curtailed and posture reduced (or reversed), while stereotyped activities (particularly grooming) were suppressed. Contralateral orientation and circling were restored by subsequently lesioning the contralateral AC as well; bilateral AC lesions significantly potentiated circling to systemic apomorphine. Contralateral locomotor asymmetry was also produced by depositing apomorphine stereotaxically into the supersensitive caudate, or by microinjecting one substantia nigra zona reticulata with muscimol (in naive rats). Both rotational responses were facilitated by injury to the ipsilateral AC. The effects of electrocoagulating the AC were generally duplicated by discrete microinjection of muscimol or gamma-vinyl GABA into this area, suggesting GABA-mediated synapses are normally operative in this part of the brain. These results do not support the claim that the AC is specifically engaged in mediating postural asymmetry in the unilaterally 6-OHDA denervated rat. Instead, we believe that impairment of neurotransmission through one AC imposes an independent and reciprocal tendency to move towards that side of the brain, as well as attenuating stereotypy and facilitating locomotion. The resultant behavioural response to systemic apomorphine shown by animals bearing these two types of lesion embodies these separate actions.

Physiological mechanisms of the "arousal response" in animals in a state of hypobiosis.

In a state of hypobiosis in white rats it was found that the previously described [4, 6] "arousal response" is characterized by a flareup of motor activity with a definite coordinated structure of the motor acts in response to a change in the animal's posture. Repeated reproduction of this response leads to a rapid summation of the electromyographic activity and a rise in the temperature. In experiments on heterothermic animals these responses are even more pronounced and are accompanied by a restoration of the original body posture and substantial temperature rise. Such an effective process of heat formation in the bodies of heterothermic animals during the "arousal response" may be associated with the mechanism of "special" awakening under conditions of reduced activity.

Low Cutaneous Evaporative Water Loss in Arboreal Frogs

Rates of cutaneous evaporative water loss were measured in seven arboreal and 11 nonarboreal anuran species under controlled environmental conditions. Areaspecific rates of cutaneous evaporative water loss of arboreal species (genera Hyla and Osteopilus) were 47% lower than those of nonarboreal species (genera Acris, Atelopus, Bufo, Gastrophryne, Rana, Scaphiopus, and Xenopus). Body and skin temperatures of arboreal species averaged 4.4 C higher than those of nonarboreal ones. Boundary layer resistance was similar in both groups of frogs and averaged 0.80 s cm⁻¹; skin resistance averaged 0.05 s cm⁻¹ in nonarboreal frogs and was 41 times higher in arboreal ones. The results of this study conflict with those of previous studies and emphasize the need for careful control of animal posture and water vapor density when measuring evaporative water loss.

Cat posture on a tilted platform.

The posture of cats trained to stand freely on a platform was studied during static tilts (up to +/- 30 degrees). Vertical projection of the center of mass on the support surface, as well as limb orientation in space and degree of limb flexion, varied minimally with platform tilt angle. The limbs' main axes were kept almost lined up with the vertical. This data indicates that postural control is simplified by strong internal constraints which limit the number of possible postural configurations. The mechanical advantages of this postural strategy are also considered. Finally, the data are discussed in the context of previously held views on the role of vestibular and neck reflex control of posture in intact animals.

Motor responses of rabbits to repetitive photic stimuli.

1. The probability of EMG responses recorded in muscles of the neck, ear, and foreand hindlimbs of a rabbit during repeated presentation of photic stimuli of moderate intensity varied from experiment to experiment but showed no tendency to decline. 2. The animal's posture has a significant effect on the probability of appearance of EMG responses. The probability of the responses was similar for all muscles tested: about 30% when the rabbit was fixed by its limbs in recumbency (posture I) and about 15% when the rabbit was in a natural (sitting) posture (posture II). 3. The latent period of responses recorded in the limb muscles showed great variability, but the maximum of the distribution occurred at 0.4–0.6 sec. Involvement of the forelimb in the response of rabbits in posture I took place more rapidly than that of the hindlimb (on average by 0.23±0.02 sec); these differences were not found in rabbits in posture II. 4. It is suggested that the EMG responses to indifferent stimuli reflect adjustments taking place primarily in the postural system, facilitating a higher level of preparedness of the animal for the appropriate activity.

Proskynesis and servility as an expression of psychotic behaviour (author's transl)

Proskynesis as an expression of submission, reverence and awe is deeply rooted in the religious and sociocultural history of man. It may be traced to the old phylogenetic submissive posture in animals, which is a pattern of behavior belonging to the group of survival instincts. Different forms of proskyneses and servility may emerge as an expression of psychotic behavior in man, reflecting a special stage of "archetypical" (C.G. Jung) consciousness. Archetypical conciousness is understood as a special step in the emergence of the human mind, thought and self-consciousness. The freedom of thinking--as the highest function of the human mind--is lost in every psychotic disorder. Archetypical consciousness with its lower stages of thinking may be typical for one kind of psychotic thinking disorder. Diagnostic problems may arise, if one does not recognize the drive of instinctive behaviour which lies behind the mere forms of human costums and religious rites.