The objects of the study including determining the relationships between movements of upper extremities identifying joint angles using a fuzzy logic system (FS). The authors analyzed ranges of joint angles and simple rhythmical movement: swinging segments of walking subjects´ arms moving in-phase (synchronously) or antiphase (reciprocally), and designed fuzzy expert system which has never been described before. The set of data to create and study fuzzy logic for identifying upper extremity angles was measured in ten volunteers. An Xbus Kit system was used to measure upper limb movements. The joint angles in the sagittal plane and angle in the frontal plane were determined and relation maps of the in-phase and antiphase movements in the contralateral and ipsilateral joints were designed. The if-then rules were derived from experimental findings and knowledge about ranges of angles and relations between angles of upper limbs during walking. The estimated values of joint angles were compared with the observed values of joint angles. Spearman's correlation coefficients were calculated for this purpose, and strong correlations for the walking speed of 3 km/h and 5 km/h were observed. The FS based on relation maps of the inphase and anti-phase movements in the contralateral and ipsilateral joints have shown to be suitable for the estimation of joint angles of upper limb during walking. The concept of the FS offers a wide range of application in rehabilitation and prostheses design.

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Head and eye compensatory movements known as vestibulo-ocular and vestibulo-cervical reflexes are essential to stay orientated in space while moving. We have used a previously developed methodology focused on the detailed mathematical description of head compensatory movements in frogs without the need for any surgical procedures on the examined specimens. Our comparative study comprising 35 species of frogs from different phylogenetic backgrounds revealed species-specific head compensatory abilities ensuring gaze stabilization. Moreover, we found a strong phylogenetic signal highlighting the great ability of compensatory head movements in families of Pyxicephalidae and Rhacophoridae from the Natatanura group. By contrast, families of Dendrobatidae and Microhylidae exhibited only poor or no head compensatory movements. Contrary to our expectation, the results did not corroborate an ecomorphological hypothesis anticipating a close relationship between ecological parameters and the head compensatory movements. We did not find any positive association between more complex (3D structured, arboreal or aquatic) habitats or more saltatory behavior and elevated abilities of head compensatory movements. Moreover, we found compensatory movements in most basal Archeobatrachia, giving an indication of common ancestry of these abilities in frogs that are variously pronounced in particular families. We hypothesize that the uncovered proper gaze stabilization during locomotion provided by the higher head compensatory abilities can improve or even enable visual perception of the prey. We interpret this completely novel finding as a possible gyroscopic advantage in a foraging context. We discuss putative consequences of such advanced neuromotor skills for diversification and ecological success of the Natatanura group.

Abstract. The article introduces systems and methods of a controllable rotational platform used for measuring compensatory movement of small animals. The system, based on a camera subsystem, is located on a mechanical platform powered by a set of three actuators. The subsystems and methods allow to measure angles of the platform's orientation in space and body segment angles in both anatomical and Earth's coordinate systems. The methods of video processing, selection of measurement parameters and detection of anatomical angles are thoroughly described in this article. The study also deals with the software designed in MatLab®, which controls the platform, records and processes videos, and obtains angles for the movement analysis. The system was tested for measuring a head rotation of a small reptile/amphibian and monitored reflective markers on the creature's body by the camera system. This method has never been described before. The new subsystems of the platform and methods for monitoring animal's head compensatory movements can be used in studies of the neural system and its evolution.