Movement Responses Research Articles

The Relationship Between Soleus H-Reflex Following Standing GVS and Postural Control Responses on Firm and Foam Surfaces: An Exploratory Study

Background: The vestibular postural control system affects standing stability on an unstable surface. However, it is unclear whether maintaining a standing position on different surfaces alters lateral vestibulospinal tract (LVST) excitability and body control responses following vestibular stimulation. This study aimed to investigate the relationship between the soleus H-reflex following galvanic vestibular stimulation (GVSH), a measure of LVST, and post-stimulus body movement responses while standing with eyes closed on different surfaces. Methods: Twelve healthy volunteers (mean age 20.4 ± 0.5 years, 7 females) performed eyes-closed standing GVSH on firm and foam surfaces. Body control responses in each condition were evaluated using an inertial measurement unit to monitor neck and pelvic movements, along with surface electromyography to assess muscle activity in the tibialis anterior and soleus muscles. Body responses to the GVS were averaged over up to a second after tibial nerve stimulation. Results: We observed a significant negative correlation between the H-wave amplitude of the GVSH on the firm surface and the tibialis anterior muscle activity following stimulation (r = −0.666, p = 0.018). No significant differences were observed during the eyes-closed standing GVSH on either firm or foam surfaces (p = 0.568). Conclusions: Postural maintenance in response to vestibular stimulation may contribute to body stability by regulating tibialis anterior muscle contraction via the LVST. Our findings may help elucidate the neural activity of vestibular function-related standing postural control responses.

Alpha6-containing GABAA receptors - Novel targets for the treatment of schizophrenia.

α6-containing GABAA receptors (α6GABAARs) are strongly expressed in cerebellar granule cells and are of central importance for cerebellar functions. The cerebellum not only is involved in regulation of motor activity, but also in regulation of thought, cognition, emotion, language, and social behavior. Activation of α6GABAARs enhances the precision of sensory inputs, enables rapid and coordinated movement and adequate responses to the environment, and protects the brain from information overflow. The cerebellum has strong connections to multiple brain regions via closed loop circuits and is also extensively connected with the dopamine system in the prefrontal cortex, that initiates the execution of behavior. Patients suffering from schizophrenia exhibit an impaired structure and function of the cerebellum and an impaired GABAergic transmission at α6GABAARs. This also impairs the function of the dopamine system, can explain a variety of schizophrenia symptoms observed, and might be one of the pathophysiological causes of schizophrenia. Enhancing GABAergic transmission at α6GABAARs should thus reduce the symptoms of schizophrenia. This recently has been confirmed by demonstrating that positive allosteric modulators with high selectivity for α6GABAARs can reduce positive and negative symptoms and cognitive impairment of schizophrenia in several animal models of this disorder. So far, the beneficial actions of these modulators have been demonstrated in animal models of neuropsychiatric disorders, only. Future human studies have to investigate the safety and possible side effects of these modulators and to clarify, to which extent individual symptoms of schizophrenia can be reduced by these drugs in patients during acute and chronic dosing.

Conflict and Urban Mobility: Challenges and Responses to Free Movement in Belfast during the Troubles

The era of the Troubles in Belfast brought both challenges to free movement and grassroots responses to such challenges. The conflict itself inspired divisions and barriers to mobility within the city, notably including the establishment of British Army checkpoints and the construction of various “peace walls” under the direction of the British Government. While the geospatial significance of the Troubles remains a popular and necessary subject of discourse within scholarship on the conflict, less attention has been given to considering its relative impact on people's daily lives. Interrogating the question of impartiality in conflict-related polices, such as the Falls Road Curfew and internment, helps contextualize disproportionate disruptions to mobility in the city. Additionally, conflict-related violence frequently impacted access to transportation, contributing to community-based initiatives to improve movement throughout the city, notably the introduction of black taxi services in the 1970s. By focusing on Belfast during the Troubles, this article considers the relationships among free movement, conflict, governments, and community-based responses to such challenges.

Study on the linkage mechanism between key strata fracture in overburden and surface subsidence during caving mining in extra-thick coal seams

Caving mining in extra-thick coal seams induces large-scale overburden movement, leading to more intense fracture processes in key strata, more significant surface subsidence, and frequent dynamic disasters in mines. This study, using the N34-2 caving face of the 17th coal seam at Junde Mine as a case study, aims to investigate the time-varying linkage mechanism between surface subsidence, microseismic characteristics, and fracture scales of the overburden’s key strata under such mining conditions. Based on Timoshenko’s theory, a bearing fracture mode for the overburden’s key strata is proposed, and corresponding fracture criteria are established. The fracture modes and step distances of the N34-2 working face were calculated theoretically and verified using microseismic localization data, showing that higher key strata are more prone to bearing failure, leading to a significant increase in fracture step distances. Numerical simulations and surface monitoring techniques were employed to comprehensively analyze the main controlling factors for surface subsidence. To further clarify the linkage mechanism between the fracture of high-position key strata and surface subsidence, the full fracture cycle under extra-thick coal seam caving mining is divided into four sub-processes: short-term fracture, rapid movement, compaction stability, and energy accumulation. The dynamic relationship between overburden movement, microseismic data, and surface subsidence responses is analyzed for each sub-process, establishing a time-varying linkage system. This approach offers a more systematic and accurate method to predict and assess the overburden movement and fracture processes, providing new insights for the prevention and control of rock burst disasters in extra-thick coal seams.

Estimating hip impact velocity and acceleration from video-captured falls using a pose estimation algorithm

Analyzing video footage of falls in older adults has emerged as an alternative to traditional lab studies. However, this approach is limited by the labor-intensive process of manually labeling body parts. To address this limitation, we aimed to validate the use of the AI-based pose estimation algorithm (OpenPose) in assessing the hip impact velocity and acceleration of video-captured falls. We analyzed 110 videos of 13 older adults (64.0 ± 5.9 years old) falling sideways in an experimental setting. By applying OpenPose to each video, we generated a time series of hip positions in the video, which were then analyzed using custom MATLAB code to calculate hip impact velocity and acceleration. These calculations were compared against ground truth measurements obtained from motion capture systems (VICON for hip impact velocity) and inertial measurement units (MC10 for hip impact acceleration). We examined the agreement between the ground truth and OpenPose measurements in terms of mean of absolute error (MAE), mean of absolute percentage error (MAPE), and bias (mean of error). Results showed that OpenPose had a good accuracy in estimating hip impact velocity with minimal bias (MAE: 0.17 ± 0.13 m/s, MAPE: 7.28 ± 5.21%; percent bias: − 1.27%). However, its estimation of hip impact acceleration (i.e., peak vertical hip acceleration at impact) showed poor accuracy (MAPE: 26.3 ± 19.4%), showing substantial underestimation in instances of high acceleration impacts (> 3.0 g). Further ANOVA analysis revealed OpenPose’s ability to discern significant differences in hip impact velocity and acceleration based on the movement response utilized during the fall (e.g., stick-like fall, tuck-and-roll, knee block). This is the first study to validate the use of a pose estimation algorithm for identifying the hip impact kinematics in video-captured falls among older adults. Future validation studies involving diverse camera settings, fall contexts, and biomechanical parameters are warranted to extend this support for using pose estimation algorithms in this field.

2D Motions Response Analysis of Floating Offshore Wind Turbine with Various Barge Shapes

Indonesia has the potential to develop floating wind turbines at sea. Therefore, its movement response needs to be analyzed to ensure that the turbine works properly. This research aims to determine the floating offshore wind turbine barge’s movement response with different floater shapes to regular waves from three different directions (0°, 45°, 90°). The movement response of the floating wind turbine was analyzed using the diffraction and radiation analysis methods in Ansys Aqwa. The research results include the RAO curve for the structure in a couple of two degrees of freedom (heave-pitch) combined with 2-dimensional analyses. The motion response of the floater cube has a maximum value heave motion 0.999 m/m and pitch motion 2.228 °/m, and, the cylindrical shape has a heave motion 1.132 m/m and pitch 10.050 °/m. Lastly, the octagonal has a heave motion 1.010 m/m and pitch 2.565 °/m. The shape and volume of each model affect the response value obtained. The simulation results in this paper can provide considerations in selecting the right floater shape to be used as a wind turbine floater foundation.

Suitability of a commercial low-cost biologging system for monitoring movement, behaviour and heart rate of grazing dairy cows

This study explored the suitability of a commercial biologging system incorporating GPS and heart rate (HR) sensors to monitor grazing cattle’s movement, behaviour and heart rate. We preliminarily tested the GPS accuracy with stationary tests and then monitored six dairy cows grazing in an alpine summer pasture for 20 days and nights. We trained a random forest model on direct observations to infer cows’ behaviours (resting, grazing, walking) from GPS movement data. We associated each GPS position with the HR (beats per minute - bpm) mean and maximum-minimum difference in the 120–second interval preceding its acquisition. The GPS sensor showed high accuracy (positioning error lower than 2 m in open sky-view and 3 m under tree canopy cover) and efficiency of position acquisition of 95% after excluding outlier positions. The efficiency of HR data acquisition was lower, peaking at 77% during daytime activity and dropping to 50% during night-time resting. The HR mean and the maximum-minimum difference were lower during resting and at night and higher during grazing, walking, and daytime. They also increased with slope and Temperature Humidity Index (THI). This study indicates that this commercial biologging system is suitable for short-term monitoring of animals’ movement, behaviour and physiological responses to varying pasture and climatic conditions, offering insights for livestock management in alpine summer pastures.

Piled-supported embankment responses to tunnelling in soft ground: An investigation of settlement and load transfer mechanisms

The escalation in infrastructure such as highways and high-speed railways has necessitated construction on soft and compressible ground, prompting the adoption of innovative solutions like piled-supported embankments. With the surge in tunnelling for transportations projects, the necessity of constructing tunnels in close proximity to piled embankments has become apparent. This study examines into settlement and load transfer mechanisms in piled-embankments affected by tunnel excavation at varying depths relative to pile lengths, employing a hypoplastic model to capture the nonlinear behaviour of soft soil. The findings indicate that the deepest tunnel caused the largest settlement, while the shallowest tunnel in led to the smallest settlement in the embankment due to pile settlements playing a significant role. The pile-soil stress ratio near the tunnel increased significantly when excavated close to pile shaft, contrasting substantially with decreased ratio in the tunnelling beneath the piled-embankment case. The bending moments in the piles exhibited differing behaviours in each case, with distinct trends observed in lateral movement and stress-induced responses. The axial load changes were influenced by factors such as negative skin friction, positive shaft resistance, and embankment weight transfer through arching, leading to unique load patterns along the pile length caused by the shallowest tunnel.

TAMSIL LINRUNG: GERAKAN DAN PERSEPSI MASYARAKAT TERHADAP KINERJA TAMSIL LINRUNG SEBAGAI WAKIL RAKYAT PADA MASA BAKTI 2004-2019

This research aims to analyze the movement and community response to Tamsil Linrung's performance during his tenure as a people's representative in the House of Representatives of the Republic of Indonesia 2004-2019. This research uses a qualitative method. Data collection is carried out through observation, interviews and documents by selecting informants to be interviewed with predetermined characteristics using purposive sampling techniques. The collected data is analyzed using thematic analysis. The results of the study show that the Tamsil Linrung movement is a systemic movement. During his tenure, the Tamsil Linrung movement was highly structured in the context of thought and actualization. With systemic movements, it creates a positive response in society at every level of social structure. The Tamsil Movement is a stimulus then in the process it receives attention, is interpreted and accepted by the community. The resulting response is a natural translation of the community that has been impacted.

An optimization method for measuring the stomata in cassava (Manihot esculenta Crantz) under multiple abiotic stresses.

As a gateway for gas exchange, pores regulate the transport of air and water in carbon assimilation, respiration, and transpiration to quickly adapt to environmental changes. Therefore, the study of stomatal movement characteristics of plants is helpful to strengthen the understanding of the mechanism of plant response to multi-environmental stress, and can improve the function of plant resistance to stresses. The stomatal movement of Arabidopsis leaves was observed by staining the stomata with rhodamine 6G, but this method has not been reported in other plant leaf stomata studies. Taking cassava as an example, the correlation between cassava stomatal movement and cassava response to stress was observed by using and improving the staining method. Rhodamine 6G is a biological stain widely used in cell biology and molecular biology. It was found that 1 μM rhodamine 6G could stain the stomata of cassava without affecting stomatal movement (n = 109, p < 0.05). In addition, we proposed that stomata fixed with 4% concentration of formaldehyde after staining were closest to the stomatal morphology of cassava epidermis, so as to observe stomatal movement under different environmental stresses more accurately. Previous methods of measuring stomatal pore size by autofluorescence of cell wall needs to fix the cells for 6 h, but Rhodamine staining can only be observed in 2 min, which greatly improves the experimental efficiency. Compared with the traditional exfoliation method (e.g., Arabidopsis), this method can reduce the damage of the leaves and observe the stomata of the whole leaves more completely, so that the experimental results are more complete. In addition, the method enables continuous leaf processing and observation. Using this method, we further compared four different cassava varieties (i.e., KU50, SC16, SC8, and SC205) and found that there are differences in stomatal density (SD) among cassava varieties, and the difference in the SD directly affects the stress resistance of cassava (n = 107, p < 0.001). This finding has important implications for studying the mechanism of plant response to environmental stress through stomata.

Manipulation of Phototactic Responses by Two-Spotted Spider Mites to Improve Performance of Miticides

Insight into phototactic responses by herbivorous crop pests may be used to manipulate their vertical distribution in crop canopies. Here, we tested the hypothesis that the deployment of specific light sources elicits positive or negative phototactic responses and can be used to enhance performance of miticide applications. We characterized movement responses by two-spotted spider mites (Tetranychus urticae) (spider mites) to seven light sources [ambient (control), UV-C, UV-B, blue, red, white, and near-infrared (NIR)] under experimental conditions. Separate experiments were conducted with/without the presence of a shelter. An analytical approach based on linear regression coefficients (intercept and slope) from observations in ascending order was used. Linear regression coefficients from UV-B indicated significantly negative phototactic bio-response. We examined settlement of spider mites when exposed to 11 light source configurations and with adaxial leaf sides facing either upwards or downwards. This experiment revealed strong positive and negative phototactic bio-responses to blue light and UV-B light, respectively. As a validation experiment, soybean plants were experimentally infested with spider mites and subjected to one of the following three treatments: (1) no treatment (control), (2) miticide [pyrethrins and Beauveria bassiana (BotaniGard Maxx)] only, and (3) a combination of blue and UV-B for 10 min immediately prior to miticide application. Integration of miticide application with prior deployment of blue and UV-B lights significantly increased the performance of miticide application. Results from this study supported the hypothesis. As a pest management approach, the integration of blue light (to elicit positive phototactic response) and UV-B (to elicit negative phototactic response) is believed to be of particular relevance to organic crop producers and/or to producers of crops for which limited numbers of miticides are registered.

The vestibular implant: effects of stimulation parameters on the electrically-evoked vestibulo-ocular reflex.

The vestibular implant is a neuroprosthesis which offers a potential treatment approach for patients suffering from vestibulopathy. Investigating the influence of electrical stimulation parameters is essential to improve the vestibular implant response. Optimization of the response focuses on the electrically evoked vestibulo-ocular reflex. It aims to facilitate high peak eye velocities and adequate alignment of the eye movement responses. In this study, the basic stimulation parameters of the vestibular implant were tested for their effect on the electrically evoked vestibulo-ocular reflex. Four stimulation parameters, including the stimulation amplitude, phase duration, stimulus rate and speed of change of stimulation, were systematically tested in a cohort of nine subjects with a vestibulo-cochlear implant. These parameters were tested to evaluate their effect on fitting settings (i.e., threshold of activation, upper comfortable limit and dynamic range) as well as on the electrically evoked vestibulo-ocular reflex (peak eye velocity and alignment). It was confirmed that, in addition to current amplitude, the peak eye velocity of the response can be increased by increasing the phase duration and pulse rate. Both parameters have little effect on the alignment of the eye response. However, a longer phase duration decreased the range between the threshold of activation and the upper comfortable limit of the electrical stimulation (i.e., dynamic range). Furthermore, these results show that next to the amplitude of the stimulation, the speed of change in stimulation has a determinative positive effect on the peak eye velocity. The observations in this study imply that the vestibular implant response, in terms of peak eye velocity, can be optimized with a higher pulse rate and longer phase duration. However, this comes at a trade-off between the dynamic range and power consumption. This study provides essential insights for fitting strategies in future vestibular implant care.

Transcriptomic dynamics of ABA response in Brassica napus guard cells

Drought has a significant, negative impact on crop production; and these effects are poised to increase with climate change. Plants acclimate to drought and water stress through diverse physiological responses, primarily mediated by the hormone abscisic acid (ABA). Because plants lose the majority of their water through stomatal pores on aerial surfaces of plants, stomatal closure is one of the rapid responses mediated by ABA to reduce transpirational water loss. The dynamic changes in the transcriptome of stomatal guard cells in response to ABA have been investigated in the model plant Arabidopsis thaliana. However, guard cell transcriptomes have not been analyzed in agronomically valuable crops such as a major oilseed crop, rapeseed. In this study, we investigated the dynamics of ABA-regulated transcriptomes in stomatal guard cells of Brassica napus and conducted comparison analysis with the transcriptomes of A. thaliana. We discovered changes in gene expression indicating alterations in a host of physiological processes, including stomatal movement, metabolic reprogramming, and light responses. Our results suggest the existence of both immediate and delayed responses to ABA in Brassica guard cells. Furthermore, the transcription factors and regulatory networks mediating these responses are compared to those identified in Arabidopsis. Our results imply the continuing evolution of ABA responses in Brassica since its divergence from a common ancestor, involving both protein-coding and non-coding nucleotide sequences. Together, our results will provide a basis for developing strategies for molecular manipulation of drought tolerance in crop plants.

Genome-Wide Profiling of the ACTIN Gene Family and Its Implications for Agronomic Traits in Brassica napus: A Bioinformatics Study

ACTINs are key structural proteins in plants, which form the actin cytoskeleton and are engaged in numerous routine cellular processes. Meanwhile, ACTIN, recognized as a housekeeping gene, has not yet been thoroughly investigated in Brassica napus. The current research has led to the detection of 69 actin genes in B. napus, which were organized into six distinct subfamilies on the basis of phylogenetic relationships. Functional enrichment analysis, along with the construction of protein interaction networks, suggested that BnACTINs play roles in Preserving cell morphology and facilitating cytoplasmic movement, plant development, and adaptive responses to environmental stress. Moreover, the BnACTIN genes presented a wide range of expression levels among different tissues, whereas the majority experienced a substantial increase in expression when subjected to various abiotic stresses, demonstrating a pronounced sensitivity to abiotic factors. Furthermore, association mapping analysis indicated that some BnACTINs potentially affected certain key agronomic traits. Overall, our research deepens the knowledge of BnACTIN genes, promotes the cultivation of improved B. napus strains, and lays the groundwork for subsequent functional research.

Behavioural responses of common dolphins to naval sonar.

Despite strong interest in how noise affects marine mammals, little is known for the most abundant and commonly exposed taxa. Social delphinids occur in groups of hundreds of individuals that travel quickly, change behaviour ephemerally and are not amenable to conventional tagging methods, posing challenges in quantifying noise impacts. We integrated drone-based photogrammetry, strategically placed acoustic recorders and broad-scale visual observations to provide complementary measurements of different aspects of behaviour for short- and long-beaked common dolphins. We measured behavioural responses during controlled exposure experiments (CEEs) of military mid-frequency (3-4 kHz) active sonar (MFAS) using simulated and actual Navy sonar sources. We used latent-state Bayesian models to evaluate response probability and persistence in exposure and post-exposure phases. Changes in subgroup movement and aggregation parameters were commonly detected during different phases of MFAS CEEs but not control CEEs. Responses were more evident in short-beaked common dolphins (n = 14 CEEs), and a direct relationship between response probability and received level was observed. Long-beaked common dolphins (n = 20) showed less consistent responses, although contextual differences may have limited which movement responses could be detected. These are the first experimental behavioural response data for these abundant dolphins to directly inform impact assessments for military sonars.

Efficacy and Safety of Naldemedine for Opioid-Induced Constipation in Children.

Background: Naldemedine, a peripherally acting opioid μ receptor antagonist, is effective for prevention of opioid-induced constipation (OIC); however, evidence on its use in children is limited. Objective: To evaluate the efficacy and safety of naldemedine in pediatric patients with OIC. Design, Setting/Subjects: Retrospective analysis of 32 pediatric patients with OIC treated with naldemedine in a single institution in Japan from June 2017 to March 2021. Measurements: Efficacy was evaluated in 13 evaluable patients with bowel movement (BM) response, defined as those with at least three BMs in the first 7 days after naldemedine initiation and an increase of at least one BM from baseline. Safety was evaluated by examining adverse events (AEs) based on the Common Terminology Criteria for AEs (v5.0). Results: BM response was recorded in 11 of the 13 patients (85%), and the number BMs per day significantly increased from 0.43 before naldemedine to 1.00 after naldemedine (p = 0.025). The most common AE was diarrhea, observed in 16 of the 32 patients (50%), and all instances were grade 1 or 2. In three of the 16 patients, naldemedine was discontinued owing to worsening diarrhea. Conclusions: In pediatric patients, naldemedine resulted in a high rate of BM response and increased the BM frequency, indicating its efficacy. In some patients, grade 2 diarrhea required naldemedine discontinuation, suggesting that it should be used with caution in pediatric patients. Further studies are warranted to determine the optimal naldemedine dose in pediatric patients.

Does Playing an Instrument Affect Cortical Excitability? A Study in Healthy Musicians

ABSTRACT Introduction: Musicians are an excellent example of people executing the perfect intended movements. Timing, sequencing, and precision are essential for purposeful actions. While playing an instrument, musicians must make motor adjustments to perform flawless music. These motor adjustments are made through auditory, tactile, and proprioceptive feedback. This study sought to investigate the cortical excitability and sensory-motor interaction in healthy professional musicians utilizing transcranial magnetic stimulation (TMS). Subjects and Methods: Fifteen healthy professional musicians and equal number of age and sex-matched control volunteers participated in this study. Motor thresholds (at both 200 μV and 1 mV), short-interval intracortical inhibition (SICI) (within interstimulus intervals of 1–7 ms), and short-latency afferent inhibition (SAI) (within interstimulus intervals of 16–24 ms) were recorded in the dominant and nondominant flexor carpi ulnaris muscles. Results: Analysis revealed no significant differences in RMT, SICI, or SAI between healthy musicians and controls across both dominant and nondominant sides. Conclusion: Motor cortex excitability and sensorimotor integration were comparable between healthy musicians and nonmusicians. TMS offers insights into motor system function, yet voluntary movement and TMS-induced motor responses engage different neurobiological pathways. Structural and functional alterations in the sensorimotor integration of healthy musicians may not be detectable through the SAI paradigm. Thus, TMS might not effectively detect alterations in cortical excitability or sensorimotor integration resulting from long-term instrument playing.

The pericardium forms as a distinct structure during heart formation.

The heart integrates diverse cell lineages into a functional unit, including the pericardium, a mesothelial sac that supports heart movement, homeostasis, and immune responses. However, despite its critical roles, the developmental origins of the pericardium remain uncertain due to disparate models. Here, using live imaging, lineage tracking, and single-cell transcriptomics in zebrafish, we find the pericardium forms within the lateral plate mesoderm from dedicated anterior mesothelial progenitors and distinct from the classic heart field. Imaging of transgenic reporters in zebrafish documents lateral plate mesoderm cells that emerge lateral of the classic heart field and among a continuous mesothelial progenitor field. Single-cell transcriptomics and trajectories of hand2-expressing lateral plate mesoderm reveal distinct populations of mesothelial and cardiac precursors, including pericardial precursors that are distinct from the cardiomyocyte lineage. The mesothelial gene expression signature is conserved in mammals and carries over to post-natal development. Light sheet-based live-imaging and machine learning-supported cell tracking documents that during heart tube formation, pericardial precursors that reside at the anterior edge of the heart field migrate anteriorly and medially before fusing, enclosing the embryonic heart to form a single pericardial cavity. Pericardium formation proceeds even upon genetic disruption of heart tube formation, uncoupling the two structures. Canonical Wnt/β-catenin signaling modulates pericardial cell number, resulting in a stretched pericardial epithelium with reduced cell number upon canonical Wnt inhibition. We connect the pathological expression of secreted Wnt antagonists of the SFRP family found in pediatric dilated cardiomyopathy to increased pericardial stiffness: sFRP1 in the presence of increased catecholamines causes cardiomyocyte stiffness in neonatal rats as measured by atomic force microscopy. Altogether, our data integrate pericardium formation as an independent process into heart morphogenesis and connect disrupted pericardial tissue properties such as pericardial stiffness to pediatric cardiomyopathies.

Single unit electrophysiology recordings and computational modeling can predict octopus arm movement.

The octopus simplified nervous system holds the potential to reveal principles of motor circuits and improve brain-machine interface devices through computational modeling with machine learning and statistical analysis. Here, an array of carbon electrodes providing single-unit electrophysiology recordings were implanted into the octopus anterior nerve cord. The number of spikes and arm movements in response to stimulation at different locations along the arm were recorded. We observed that the number of spikes occurring within the first 100ms after stimulation were predictive of the resultant movement response. Computational models showed that temporal electrophysiological features could be used to predict whether an arm movement occurred with 88.64% confidence, and if it was a lateral arm movement or a grasping motion with 75.45% confidence. Both supervised and unsupervised methods were applied to gain streaming measurements of octopus arm movements and how their motor circuitry produces rich movement types in real time. Deep learning models and unsupervised dimension reduction identified a consistent set of features that could be used to distinguish different types of arm movements. These models generated predictions for how to evoke a particular, complex movement in an orchestrated sequence for an individual motor circuit.

Fine-scale movement response of juvenile brown trout to hydropeaking

Juvenile fish are known to be the most impacted during hydropeaking events due to stranding or uncontrolled drift resulting from changes to water depth and flow velocity. To shed light on their response to such hydraulic alterations, we coupled flume experiments with image-based fish tracking and quantified the fine-scale movement behavior of wild (n = 30) and hatchery-reared (n = 38) brown trout (Salmo trutta) parr. We exposed fish to two distinct hydropeaking treatments in a laterally inclined (14 %) flume section stocked with real cobbles to create refuge and heterogeneous hydraulic conditions. Fish were individually acclimated (20 min) to baseflow (Q = 1.6 L s-1) and then exposed to three consecutive hydropeaking events, reaching peakflows tenfold larger than baseflow (Q = 16 L s-1). We found that, within just minutes, fish exhibited fine-scale movement responses to cope with the change of hydrodynamic conditions. Fish moved perpendicular to the main flow direction to shallow areas as these became submerged during discharge increase, holding position at low velocity zones. This resulted in a significant difference (p < 0.001) in lateral occupancy of the experimental section between baseflow and peakflow. During peakflow, fish occupied specific positions around cobbles and exhibited swimming behaviors, including bow-riding and entraining, that allowed them to hold position while likely minimizing energy expenditure. As a result, swimming distance reduced 60–70 % compared to baseflow. During the decrease in discharge following peakflow, fish abandoned areas falling dry by moving laterally. In the treatment with the larger down-ramping rate, the time to initiate relocation was lower while the relocation speed was higher. This study shows that, for the conditions investigated here, brown trout parr is capable of swiftly deploying multiple behavioral responses to navigate rapid changes in hydrodynamic conditions. These findings can be incorporated into habitat modeling and improve our capacity to inform hydropeaking mitigation efforts.