Cyclic Motion Research Articles

Human short-latency reflexes show precise short-term gain adaptation after prior motion.

The central nervous system adapts the gain of short-latency reflex loops to changing conditions. Experiments on biomimetic robots showed that reflex modulation could substantially increase energy efficiency and stability of periodic motions if, unlike known mechanisms, the reflex modulation both acted precisely on the muscles involved and lasted after the motion. This study tests the presence of such a mechanism by having participants repeatedly rotate either their right elbow or shoulder joint, before perturbing either joint. The results demonstrate a mechanism that modulates short-latency reflex gains after prior motion with joint-specific precision. Enhanced gains were observed hundreds of milliseconds after movement cessation, a time scale well-suited to quickly adapt overall periodic motion cycles. A serotonin antagonist significantly decreased these post-movement gains diffusely across joints. But blocking serotonin did not affect the joint-specificity of the gain scaling more than a placebo, suggesting that serotonin sets the overall reflex gain across joints after movement by an effect that is modulated in a joint-specific manner by an unidentified neural circuit. These results confirm the existence of a new, joint-specific, fast, persistent adaptation of short-latency reflex loops induced by motion in human arms.

Comparison Between InterCriteria and Correlation Analyses over sEMG Data from Arm Movements in the Horizontal Plane

InterCriteria analysis (ICrA) and two kinds of correlation analyses, Pearson (PCA) and Spearman (SCA), were applied to surface electromyography (sEMG) signals obtained from human arm movements in the horizontal plane. Ten healthy participants performed ten movements, eight of which were cyclic. Each cyclic movement (CM) consisted of flexion and extension phases with equal duration (10 s, 6 s, 2 s, and 1 s) and two 5 s rest poses between them. The CMs were performed with and without an added load of 0.5 kg on the wrists of the participants. The sEMG signals from six different muscles or separate muscle heads (m. deltoideus pars clavicularis, m. deltoideus pars spinata, m. brachialis, m. anconeus, m. biceps brachii, and m. triceps brachii long head) were recorded and used to compare the results of the ICrA, PCA, and SCA. All three methods found identical consonance pairs for the flexion and extension CM phases. Additionally, PCA detected two more consonance pairs in the extension phases. In this investigation, ICrA, PCA, and SCA were proven to be reliable tools when applied separately or in combination for sEMG data. These three methods are appropriate for researching arm movements in the horizontal plane and experimental protocol revision.

The role of synaptic protein NSF in the development and progression of neurological diseases.

This document provides a comprehensive examination of the pivotal function of the N-ethylmaleimide-sensitive factor (NSF) protein in synaptic function. The NSF protein directly participates in critical biological processes, including the cyclic movement of synaptic vesicles (SVs) between exocytosis and endocytosis, the release and transmission of neurotransmitters, and the development of synaptic plasticity through interactions with various proteins, such as SNARE proteins and neurotransmitter receptors. This review also described the multiple functions of NSF in intracellular membrane fusion events and its close associations with several neurological disorders, such as Parkinson's disease, Alzheimer's disease, and epilepsy. Subsequent studies should concentrate on determining high-resolution structures of NSF in different domains, identifying its specific alterations in various diseases, and screening small molecule regulators of NSF from multiple perspectives. These research endeavors aim to reveal new therapeutic targets associated with the biological functions of NSF and disease mechanisms.

Utilization of the Resonance Behavior of a Tendon-Driven Continuum Joint for Periodic Natural Motions in Soft Robotics

Continuum joints use structural elastic deformations to enable joint motion, and their intrinsic compliance and inherent mechanical robustness are envisioned for applications in which the robot, the human, and the environment need to be safe during interaction. In particular, the intrinsic compliance makes continuum joints a competitor to soft articulated joints, which require additional integrated spring elements. For soft articulated joints incorporating rigid and soft parts, natural motions have been investigated in robotics research to exploit this energy-efficient motion property for cyclic motions, e.g., locomotion. To the best of the author’s knowledge, there is no robotic system to date that utilizes the natural motion of a continuum joint under periodic excitation. In this paper, the resonant behavior of a tendon-driven continuum joint under periodic excitation of the torsional axis is experimentally investigated in a functional sense. In the experiments, periodic inputs are introduced on the joint side of a tendon driven continuum joint with four tendons. By modulating the pretension of the tendons, both the resonant frequency and the gain can be shifted, from 3 to 4.3 Hz and 2.8 to 1.4, respectively, in the present experimental setup. An application would be the rotation of a humanoid torso, where gait frequencies are synchronized with the resonant frequency of the continuum joint.

National archetypes in the master’s biography (the case study of «Veselka», the symphony fantasy by Viktor Telychko)

The thesis objective is to identify the key national archetypes that are crucial for a creative personality’s lifelong creativity; to reveal the specifics of their explication in «Veselka», Viktor Telychko’s symphonic fantasy. The research methodology is based on the complex approach and embraces a number of the following methods: biographical – by involving the key events of the master’s being; culture studies – by characterizing civilizational impacts reflected in the master’s conscience; semiotic – by interpreting ancient symbols implemented by the suggested artistic sample; music studies – by considering the genre and style-forming parameters of the opus; analytical – by working on the body of research related to the aforementioned problematic field; systemic – by comprehensive view on the research subject; theoretic generalization – by summarizing the thesis results. Science novelty. For the first time ever, the dominant national archetypes of a master’s chronicle were identified, and their manifestation was revealed within an artistic artefact. Conclusions. An archetype is an unconscious fundamental scheme of notions, signs and symbols common for the whole humanity. For Ukrainian culture, the following ones are critical: home, Motherland, parents, land, temple, light, etc. Most of them are represented by the biographies of prominent masters. The composer’s practice by Viktor Telychko broadcasts the phenomena under consideration through folklore, which is a constituent of his opuses. In «Veselka» symphony fantasy, they appear as a content element able to represent significant information about the Ukrainians’ mentality and the author’s ontological strategy. The dominant ancient images of the artwork are as follows: Motherland revealed through the author’s connection with the native location and quoting on Zakarpattia’s songs; the native land that means life, wisdom, spiritual power, appeal to the native location; father embodying peace, calmness, emotional support; the circle that represents eternity, rebirth, aspiring after self-perfection for the evolution of the native land. The manifestation, which is the structure of a music sample similar to a cyclic motion; the teacher who reveals the issue of guidance appealing to the artistic heritage of the prominent masters of the region; the main character who reflects striving for eternal ideals characteristic of Victor Telychko and is interpreted via high-hearted and persistent intonations; love that celebrates deep lyrical and poetic feelings and appears as the mental basis of Ukrainian sensuality. The masterpiece is united by the spiritual light archetype (the rainbow) that manifests hope and joy.

Performance evaluation of the static thrust and efficiency of an actuated biomimetic jellyfish model

Abstract This study offers an in-depth analysis of a jellyfish-inspired robotic model designed to simulate the expansion and contraction mechanisms found in natural jellyfish. By employing variable Duty Cycles to replicate the cyclic motions of the jellyfish, the thrust generation of the model is measured through static thrust assessments using a load cell, while its efficiency is evaluated using the Thrust-to-Power Ratio, TPR. The findings indicate that increasing the amplitude of the motion leads to more complex wave patterns, which in turn reduce the peak-to-peak force generated. Specifically, a 25% increase in the A/D ratio results in a significant 30% decrease in static thrust. It was observed that higher actuation frequencies do not notably influence thrust generation when the A/D ratio remains constant. Importantly, the TPR was found to be highest at an A/D ratio of 0.10, with an increase of up to 6% observed at higher Duty Cycles, suggesting that smaller actuation amplitudes are more efficient in enhancing thrust performance. These results highlight the critical role of amplitude in the efficiency of static thrust generation within a given Duty Cycle, emphasizing that lower amplitudes generally lead to higher efficiency. The study underscores the importance of optimizing both geometric and kinematic parameters for improved propulsion performance. It suggests that future research should focus on fine-tuning A/D ratios and Duty Cycles, as well as exploring alternative geometric configurations and materials to further enhance the hydrodynamic performance of jellyfish-inspired robots. The insights gained from this study provide a valuable foundation for developing more efficient and effective bio-inspired underwater vehicles.

Effect of asymptomatic intervertebral flexion patterns on lumbar disc pressure: A finite element analysis study.

Movement patterns may be a factor for manipulating the lumbar load, although little information is yet available in the literature about the relationship between this variable and intervertebral disc pressure (IDP). A finite element model of the lumbar spine (49-year-old asymptomatic female) was used to simulate intervertebral movements (L2-L5) of 127 asymptomatic participants. The data from participants that at least completed a simulation of lumbar vertebral movement during the first 53% of a movement cycle (flexion phase) were used for further analyses. Then, for each vertebral angular motion curve with constant spatial peaks, different temporal patterns were simulated in two stages: (1) in lumbar pattern exchange (LPE), each vertebral angle was simulated by the corresponding vertebrae of other participants data; (2) in vertebral pattern exchange (VPE), vertebral angles were simulated by each other. The k-mean algorithm was used to cluster two groups of variables; peak and cumulative IDP, in both stages of simulations (i.e., LPE and VPE). In the second stage of the simulation (VPE), Kendall's tau was utilized to consider the relationship between different temporal patterns and IDPs for each individual lumbar level. Cluster analyses showed that the temporal movement pattern did not exhibit any effect on the peak IDP while the cumulative IDP changed significantly for some patterns. Earlier involvement in lumbar motion at any level led to higher IDP in the majority of simulations. There is therefore a possibility of manipulating lumbar IDP by changing the temporal pattern with the same ROM, in which optimal distribution of the loads among lumbar levels may be applied as preventive or treatment interventions. Evaluating load benefits, such as load, on biomechanically relevant lumbar levels, dynamically measured by quantitative fluoroscopy, may help inform interventional exercises.

Brain-body-task co-adaptation can improve autonomous learning and speed of bipedal walking.

Inspired by animals that co-adapt their brain and body to interact with the environment, we present a tendon-driven and over-actuated (i.e., n joint, n+1 actuators) bipedal robot that (i) exploits its backdrivable mechanical properties to manage body-environment interactions without explicit control, and (ii) uses a simple 3-layer neural network to learn to walk after only 2 minutes of 'natural' motor babbling (i.e., an exploration strategy that is compatible with leg and task dynamics; akin to childsplay). This brain-body collaboration first learns to produce feet cyclical movements 'in air' and, without further tuning, can produce locomotion when the biped is lowered to be in slight contact with the ground. In contrast, training with 2 minutes of 'naive' motor babbling (i.e., an exploration strategy that ignores leg task dynamics), does not produce consistent cyclical movements 'in air', and produces erratic movements and no locomotion when in slight contact with the ground. When further lowering the biped and making the desired leg trajectories reach 1cm below ground (causing the desired-vs-obtained trajectories error to be unavoidable), cyclical movements based on either natural or naive babbling presented almost equally persistent trends, and locomotion emerged with naive babbling. Therefore, we show how continual learning of walking in unforeseen circumstances can be driven by continual physical adaptation rooted in the backdrivable properties of the plant and enhanced by exploration strategies that exploit plant dynamics. Our studies also demonstrate that the bio-inspired co-design and co-adaptations of limbs and control strategies can produce locomotion without explicit control of trajectory errors.

Hippotherapy As An Effective Treatment Strategy For Paediatric Population With Disabilities - A Literature Review

Background: Hippotherapy is an equine-assisted therapeutic method for the development of physical, occupational, and emotional performance in people suffering from various maladies. The neurophysiology of hippotherapy is characterized by the cyclical rhythmic movement of the horses, which is a kind of sensory input providing the rider with the information needed to maintain the proprioceptive and vestibular systems. It is the act of falling and jumping process that encourages neural pathways responsible for the development of the motor system which gradually results in the development of balance and coordination. To wit, the motion of those animals is one such that they imitate the normal human body’s walking pattern and in effect, like physiotherapy, they provide familiarity and thereby help in reskilling the rider’s core muscles and postural alignment. Furthermore, the relationship between the horse and the human being can also contribute to the emotional and spiritual side of the human being, thus, resulting in a more holistic approach to therapy that could be shown in practice through such modes as horse therapy. Methodology: We performed literature searching multiple electronic databases. The searches generated 50 potentially relevant studies. After applying inclusion and exclusion criteria, eliminating repeated articles, and critically evaluating the obtained results, nine papers were selected for the analysis. The selected papers were published between the period of January 2019 to July 2024. This comprised two cross-sectional studies, one experimental study, one exploratory study, one randomized controlled trial, and one survey investigation. Results: This literature review noticed a connection between hippotherapy and observable improvements in balance, coordination, gait, motor functions, cognitive functions, flexibility, functional mobility in children with disabilities. Conclusion: Hippotherapy has benefited balance, coordination, gait, motor functions, cognitive functions, flexibility, and functional mobility in children with disabilities, and thus, it should be considered as a treatment strategy for treating children with disabilities.

THE DEVELOPMENT OF STRENGTH QUALITIES OF YOUNG PEOPLE IN PHYSICAL EDUCATION LESSONS

The article raises the issues of the development of strength abilities as a directed pedagogical process. The author conducted a study on the development of strength qualities of boys and girls aged 16-17 who are engaged in physical education classes, and carried out a practical experiment on the development of strength abilities among 16-17-year-old people. As a result of this experiment, the author came to a conclusion that the use of exercises for the development of strength and endurance makes it possible to lay the foundations for further physical development of young people. At this stage, the skills of precise exercise performance are formed, the principles of proper coordination of movements are applied. The training programme includes exercises that require cyclic movements.

Design of the Torsional Properties Measurement Stand for Rubber-Metal Elements in Motor Vehicles

Abstract This paper describes design and application of a torsional property measurement stand used for analyzing rubber-metal components. The paper covers mechanical, electrical and control systems. Design of the stand takes into consideration reusing existing components, that come from a measuring stand that was used for analyzing automotive dual-mass flywheels. Paper covers initial design proposal as well as final design in CAD model form and the finished assembled stand. A Section of this paper is dedicated to describing the components and software used to control the stand and collect data from sensor. Programming of the excitation movement cycle in TIA-Portal software is also covered in this section. Lastly it covers experimental analysis. Our findings and evaluation of the machine itself is found in the conclusion chapter.

A narrative review of velocity-based training best practice: The importance of contraction intent vs. movement speed.

Explosive movements requiring high force and power outputs are integral to many sports, posing distinct challenges for the neuromuscular system. Traditional resistance training can improve muscle strength, power, endurance, and range of motion; however, evidence regarding its effects on athletic performance, such as sprint speed, agility, and jump height, remains conflicting. The specificity of resistance training movements, including velocity, contraction type, and joint angles affects performance outcomes, demonstrates advantages when matching training modalities with targeted sports activities. However, independent of movement speed, the intent to contract explosively (ballistic) has also demonstrated high velocity-specific training adaptations. The purpose of this narrative review was to assess the impact of explosive or ballistic contraction intent on velocity-specific training adaptations. Such movement intent may predominantly elicit motor efferent neural adaptations, including motor unit recruitment and rate coding enhancements. Plyometrics, which utilize rapid stretch-shortening cycle (SSC) movements may augment high-speed movement efficiency and muscle activation, possibly leading to improved motor control through adaptations like faster eccentric force absorption, reduced amortization periods, and quicker transitions to explosive concentric contractions. An optimal training paradigm for power and performance enhancement might involve a combination of maximal explosive intent training with heavier loads and plyometric exercises with lighter loads at high velocities. This narrative review synthesizes key literature to answer whether contraction intent or movement speed is more critical for athletic performance enhancement, ultimately advocating for an integrative approach to resistance training tailored for sports-specific explosive action.

Deconstructing the frame effect.

The perception of an object's location is profoundly influenced by the surrounding dynamics. This is dramatically demonstrated by the frame effect, where a moving frame induces substantial shifts in the perceived location of objects that flash within it. In this study, we examined the elements contributing to the large magnitude of this effect. Across three experiments, we manipulated the number of probes, the dynamics of the frame, and the spatiotemporal relationships between probes and the frame. We found that the presence of multiple probes amplified the position shift, whereas the accumulation of the frame effect over repeated motion cycles was minimal. Notably, an oscillating frame generated more pronounced effects compared to a unidirectional moving frame. Furthermore, the spatiotemporal distance between the frame and the probe played pivotal roles, with larger shifts observed near the leading edge of the frame. Interestingly, although larger frames produced stronger position shifts, the maximum shift occurred almost at the same distance relative to the frame's center across all tested sizes. Our findings suggest that the number of probes, frame size, relative probe-frame distance, and frame dynamics collectively contribute to the magnitude of the position shift.

An open-source toolbox for enhancing the assessment of muscle activation patterns during cyclical movements

Objective.The accurate temporal analysis of muscle activations is of great importance in several research areas spanning from the assessment of altered muscle activation patterns in orthopaedic and neurological patients to the monitoring of their motor rehabilitation. Several studies have highlighted the challenge of understanding and interpreting muscle activation patterns due to the high cycle-by-cycle variability of the sEMG data. This makes it difficult to interpret results and to use sEMG signals in clinical practice. To overcome this limitation, this study aims at presenting a toolbox to help scientists easily characterize and assess muscle activation patterns during cyclical movements.Approach.CIMAP(Clustering for the Identification of Muscle Activation Patterns) is an open-source Python toolbox based on agglomerative hierarchical clustering that aims at characterizing muscle activation patterns during cyclical movements by grouping movement cycles showing similar muscle activity.Main results.From muscle activation intervals to the graphical representation of the agglomerative hierarchical clustering dendrograms, the proposed toolbox offers a complete analysis framework for enabling the assessment of muscle activation patterns. The toolbox can be flexibly modified to comply with the necessities of the scientist.CIMAPis addressed to scientists of any programming skill level working in different research areas such as biomedical engineering, robotics, sports, clinics, biomechanics, and neuroscience. CIMAP is freely available on GitHub (https://github.com/Biolab-PoliTO/CIMAP).Significance.CIMAPtoolbox offers scientists a standardized method for analyzing muscle activation patterns during cyclical movements.

Optical penetration depth and periodic motion of a photomechanical strip

Liquid crystal elastomers (LCEs) containing light-sensitive molecules exhibit large, reversible deformations when subjected to illumination. Here, we investigate the role of optical penetration depth on this photomechanical response. We present a model of the photomechanical behavior of photoactive LCE strips under illumination that goes beyond the common assumption of shallow penetration. This model reveals how the optical penetration depth and the consequent photomechanically induced deformation can depend on the concentration of photoactive molecules, their absorption cross-sections, and the intensity of illumination. Through a series of examples, we show that the penetration depth can quantitatively and qualitatively affect the photomechanical response of a strip. Shallow illumination leads to monotone curvature change while deep penetration can lead to non-monotone response with illumination duration. Further, the flapping behavior (a cyclic wave-like motion) of doubly clamped and buckled strips that has been proposed for locomotion can reverse direction with sufficiently large penetration depth. This opens the possibility of creating wireless light-driven photomechanical actuators and swimmers whose direction of motion can be controlled by light intensity and frequency.

Interaction of motor behaviour, cortical oscillations and deep brain stimulation in Parkinson disease

Abstract Recent progress in the study of Parkinson's disease (PD) has highlighted the pivotal role of beta oscillations within the basal ganglia-thalamo-cortical network in modulating motor symptoms. Predominantly manifesting as transient bursts, these beta oscillations are central to the pathophysiology of PD motor symptoms, especially bradykinesia. Our central hypothesis is that increased bursting duration in cortex, coupled with kinematics of movement, disrupts the typical flow of neural information, leading to observable changes in motor behavior in PD. To explore this hypothesis, we employed an integrative approach, analyzing the interplay between moment-to-moment brain dynamics and movement kinematics, and the modulation of these relationships by therapeutic deep brain stimulation (DBS). Local field potentials were recorded from the hand motor (M1) and premotor cortical (PM) areas, and internal Globus Pallidus (GPi) in 26 PD patients undergoing DBS implantation surgery. Participants executed rapid alternating hand movements in 30-second blocks, both with and without therapeutic pallidal stimulation. Behaviorally, the analysis revealed bradykinesia, with hand movement cycle width increasing linearly over time during DBS-OFF blocks. Crucially, there was a moment-to-moment correlation between M1 low beta burst duration and movement cycle width, a relationship that dissipated with therapeutic DBS. Further analyses suggest that high gamma activity correlates with enhanced motor performance with DBS-ON. Regardless of the nature of coupling, DBS’s modulation of cortical bursting activity appeared to amplify the brain signals’ informational content regarding instantaneous movement changes. Our findings underscore that DBS significantly reshapes the interaction between motor behavior and neural signals in PD, not only modulating specific bands but also expanding the system's capability to process and relay information for motor control. These insights shed light on the possible network mechanisms underlying DBS therapeutic effects, suggesting a profound impact on both neural and motor domains.

Development of a kinematic model for a free kinematic forming process to compute the tool trajectory

AbstractIn the production of hybrid composites made of thermoplast and metal sheets, certain limitations in the linear forming process can be overcome through a free kinematic forming process. This process involves distributing the thermoplast press mass using a tumbling or cyclic rolling movement of the forming tool. Due to this special kinematics, only a small part of the tool is ever in engagement with the workpiece, so the component is formed incrementally. Therefore, the final geometry does not have to be created in one stroke but can be carried out step by step in several partial strokes. In order to determine the optimal trajectory of the forming tool, the kinematic interplay between the workpiece, forming tool, and toolpath should be numerically captured in a mathematical model. The specific toolpath depends on the component being formed, as well as the actual geometry of the forming tool. In this research, the free kinematic forming process is modeled and the optimal toolpath is determined using a genetic algorithm. The optimal toolpath enables a uniform distribution of the thermoplast to a specified thickness and collisions between the upper and lower tool are avoided. This enables key insights into the free kinematic forming process and opens up further avenues of research for this innovative and future‐oriented manufacturing concept.

Device-Less Data-Driven Cardiac and Respiratory Gating Using LAFOV PET Histo Images.

Background: The outstanding capabilities of modern Positron Emission Tomography (PET) to highlight small tumor lesions and provide pathological function assessment are at peril from image quality degradation caused by respiratory and cardiac motion. However, the advent of the long axial field-of-view (LAFOV) scanners with increased sensitivity, alongside the precise time-of-flight (TOF) of modern PET systems, enables the acquisition of ultrafast time resolution images, which can be used for estimating and correcting the cyclic motion. Methods: 0.25 s so-called [18F]FDG PET histo image series were generated in the scope of for detecting respiratory and cardiac frequency estimates applicable for performing device-less data-driven gated image reconstructions. The frequencies of the cardiac and respiratory motion were estimated for 18 patients using Short Time Fourier Transform (STFT) with 20 s and 30 s window segments, respectively. Results: The Fourier analysis provided time points usable as input to the gated reconstruction based on eight equally spaced time gates. The cardiac investigations showed estimates in accordance with the measured pulse oximeter references (p = 0.97) and a mean absolute difference of 0.4 ± 0.3 beats per minute (bpm). The respiratory frequencies were within the expected range of 10-20 respirations per minute (rpm) in 16 out of 18 patients. Using this setup, the analysis of three patients with visible lung tumors showed an increase in tumor SUVmax and a decrease in tumor volume compared to the non-gated reconstructed image. Conclusions: The method can provide signals that were applicable for gated reconstruction of both cardiac and respiratory motion, providing a potential increased diagnostic accuracy.

Functioning of unidirectional ventilation in flying hawkmoths evaluated by pressure and oxygen measurements and X-ray video and tomography.

Flying sphingids generate unidirectional ventilation with an inflow through the anterior thoracic spiracles and an outflow through the posterior thoracic spiracles. This phenomenon was documented by the CO2 emission and tracheal air pressure in split-chamber experiments in preceding studies. In the present study, we evaluated the function of the air pump mechanism by measuring the tracheal pressure and PO2in the air sacs and monitoring the wing beat using photocells. Microelectrodes recorded the abdomen flexing muscles and abdominal transverse muscle septum. The crucial structure was the vertical mesophragma, with longitudinal flight muscles attached anteriorly and large fused metathoracic air sacs posteriorly, continuous to the first abdominal segment. Longitudinal flight muscles and abdomen lifting muscles contracted synchronously, producing positive pressure pulses within the mesothoracic air sacs. In the scutellar air sacs, the PO2with starting full flight was elevated to 18-20 kPa, with a pressure increase of 35-50 Pa. In contrast, in the metathoracic air sacs, the O2 concentration during flight could rise to 10 kPa, then decline to 5±1 kPa. The metathoracic air sacs provided compliance for ventilation by the flight muscles. The initial rise and subsequent decrease of the PO2in these posterior metathoracic air sacs indicated the unidirectional flow path of the air used. Serial X-ray frames of flying Acherontia atropos visualised the cyclic phragma movement and volume changes in the metathoracic air sacs. The results showed that the contracting dorsolongitudinal flight muscles expanded the metathoracic air sacs, acting as a suction pump.

Perceived Trajectories of Cyclic Sound Movement

Binaural beats are a phenomenon that occurs during dichotic stimulation due to binaural integration. It takes the form of cyclic movement of the sound image in the listener’s acoustic space when the beat frequency range is below 3 Hz. Our subjects used the inserted earphones to listen to the stimuli that created a sense of sound movement due to changes in the interaural time difference (ITD). We used three types of dichotic stimuli which simulated smooth azimuthal cyclic movement and cyclic abrupt shifts. The ITD changes determined central or lateral positions of movement trajectories. The results confirm that both types of movement created the effect of binaural beats. The range of beats depended on the spatial position of the trajectory: in the frontal sector of acoustic space, the range of beats was greater than on the left or right. The perceived trajectories of smooth motion were shorter than the trajectories of abrupt shift. The influence of spatial position on the perceived trajectory length is interpreted from the standpoint of nonlinear features of lateralization. It is suggested that the effect of ITD pattern on the perceived trajectory length is mediated by temporal integration mechanisms of binaural hearing.