Movement Initiation Research Articles

Functional coupling between target selection and acquisition in the superior colliculus.

Survival in unpredictable environments requires that animals continuously evaluate their surroundings for behavioral targets, direct their movements toward those targets, and terminate movements once a target is reached. The ability to select, move toward, and acquire spatial targets depends on a network of brain regions, but it remains unknown how these goal-directed processes are linked by neural circuits. Within this network, common circuits in the midbrain superior colliculus (SC) mediate the selection and initiation of movements to spatial targets. However, SC activity often persists throughout movement, suggesting that the same SC circuits underlying target selection and movement initiation may also contribute to "target acquisition": stopping the movement at the selected target. Here, we examine the hypothesis that SC functional circuitry couples target selection and acquisition using a "default motor plan" generated by selection-related neuronal activity. Recordings from intermediate and deep layer SC neurons in mice performing a spatial choice task demonstrate that choice-predictive neurons, including optogenetically identified GABAergic neurons whose activity mediates target selection, exhibit increased activity during movement to the target. By recording from rostral and caudal SC in separate groups of mice, we also revealed higher activity in rostral than caudal neurons during target acquisition. Finally, we used an attractor model to examine how-invoking only SC circuitry-caudal SC activity related to selecting an eccentric target could generate higher rostral than caudal acquisition-related activity. Overall, our results suggest a functional coupling between SC circuits for target selection and acquisition, elucidating a key mechanism for goal-directed behavior.NEW & NOTEWORTHY How do neural circuits ensure that selected targets are successfully acquired? Here, we examine whether choice-related activity in the superior colliculus (SC) promotes a motor plan for target acquisition. By demonstrating that choice-predictive SC neurons-including GABAergic neurons-remain active throughout movement, while the activity of rostral SC neurons increases during acquisition, and by recapitulating these dynamics with an attractor model, our results support a role for SC circuits in coupling target selection and acquisition.

The spatiotemporal control of expert tennis players when returning first serves: A perception-action perspective

ABSTRACT The aim of the current experiment was to examine the spatiotemporal control of expert tennis players while executing first service returns within a representative experimental setting. We recruited and tested 12 male expert tennis players in hard courts. A comprehensive analysis of the timing (eleven temporal variables analysed at 300 Hz) and performance success of the return actions were carried out, while simultaneously considering task constraints such as the accuracy and the speed of the serves. Temporal organisation of return actions were scaled relative to the server’s racket-ball contact (5 ms), an adaptation of fly-time of the split-step, which resulted in consistent landings (133 ms), and initiation of lateral movements towards the ball – with no response errors – after the server’s stroke (around 177 ms). Poorer returns occurred when responding to accurate serves accompanied by late trunk movements towards the ball. Returners scaled the timing of the response to the unfolding action of the serve in order to support both spatial and temporal accuracy. These novel findings highlight the significance of the study of fast-ball sports in representative settings and offer further detail on the spatiotemporal control of skilful perception-action.

When the going gets tough, what happens to quiet eye? The role of time pressure and performance pressure during basketball free throws

In aiming sport contexts, the quiet eye (QE) - the final ocular fixation before movement initiation - is a crucial perceptual-cognitive skill. Indeed, an extended QE permits athletes to achieve high performances, aiding optimal attentional control, particularly in situations in which athletes are "under pressure." Such situations are common in sport, especially when time runs out, and even just a few points can mean the difference between victory and defeat. Although QE has been widely investigated across several sports and tasks, no previous studies have considered both the role of time pressure and performance pressure on QE. The current study aimed to comprehend the effect of tough sport situations on QE characteristics. Accordingly, we tested basketball players (competitive-élites and semi-élites) in free throw trials, manipulating both the time available to perform the task and the relevance of the performance. The results showed that time pressure and performance pressure impaired QE characteristics, regardless of expertise levels. Also, time pressure led to a decrease in free throw accuracy. Interestingly, the match between task demands and the ability to cope seemed to play a role on QE, especially in the competitive-élite players, with negative QE characteristics (short and late) when task demands exceeded the ability to cope. These findings suggest that QE research and QE training protocols should account for time pressure, performance pressure, and the players' perceived ability to cope with the requested task.

First evidence of yawn contagion in a wild monkey species

Yawn contagion occurs when individuals yawn in response to the yawn of others (triggers). This is the first account of yawn contagion in wild geladas (Theropithecus gelada), a monkey species that shows yawn contagion in captivity and is organized in core units (one-male/bachelor groups) forming multilevel associations. In a population of geladas from the Kundi plateau (Ethiopia) we found that the yawning response was highest when geladas could perceive a triggering yawn, which confirms that yawn contagion is present in the wild. Yawn duration, mouth-opening degree and presence/absence of vocalisation (possibly modulating yawn detectability) did not affect the likelihood of contagion. Males and females, known to be both implicated in movement initiation within groups, were similarly powerful as yawn triggers. Instead, group membership and responder sex had a significant role in shaping the phenomenon. Yawn contagion was highest between individuals belonging to different core units and males were most likely to respond to others’ yawns. Because males have a non-negligible role in inter-group coordination, our results suggest that yawn contagion may have a communicative function that goes beyond the basic unit level.

Physiological characterisation of tissue differentiation in response to desiccation in the homoiochlorophyllous dicot resurrection plant Craterostigma pumilum Hochst

Resurrection plants are a polyphyletic group of angiosperms which display true desiccation tolerance (DT) - the ability to survive near complete loss of cellular water for extended periods while recovering metabolic competence upon watering. This is achieved by employing tailored protection behaviours depending on the relative state of (de)hydration. Recent work has raised interest in desiccation-associated changes related to tissue destiny in desiccation tolerant vegetative tissues. Homoiochlorophyllous species, such as those in the Craterostigma genus, maintain their photosynthetic apparatus during the dehydration process, employing considerable protection thereof. In the current study, detailed phenotypic characterisation and pulse-amplitude modulated chlorophyll fluorometry were used to identify the critical water contents at which key physiological changes occur in leaves of Craterostigma pumilum and how this relates to desiccation-associated differentiation between Tip and Base tissues of leaf blades. This differentiation appeared to be realised only during early rehydration and after initial water movement through the leaf tissues. This work provides strong evidence for the existence of desiccation-associated tissue differentiation in C.pumilum and, potentially, other homoiochlorophyllous resurrection plants.

Moderately radical? Stakeholders' perspectives on societal roles and transformative potential of organic agriculture

Organic agriculture has achieved many important milestones over the last three decades. Despite these achievements, criticism of the mainstream model of agriculture, which had originally contributed to the success of the organic sector, is potentially having a negative impact on its transformative potential. The main goal of this paper is to provide further empirical evidence that captures ongoing changes in the social discourse of the organic movement. Specific attention is paid to the formation of a relationship between the organic movement and other alternative initiatives and conventional agriculture, based on the potentially shared values of sustainability as articulated in the Organic 3.0 strategy. The empirical study was conducted in the Czech Republic. The study identifies three distinct discourses that show how different groups of stakeholders form their expectations towards organic farming. The findings of our study suggest that their views differ significantly when it comes to the functions of organic farming in society. Results of the study show that the dominant social discourse on organic farming principally conveys the Organic 3.0 strategy.

Improved analytical model for the relaxation process of aeolian sand transport.

The process from the initial sand movement to sand flux saturation is described as the relaxation of aeolian sand transport. For this relaxation process, most existing models distinguish the conditions with and without upwind sand flux, therefore lacking in generality. An improved analytical model is proposed in this paper, which incorporates the phenomena of "overshoot" and "equilibrium" and the concept of the region of initiation by fluid, and is able to unify the cases with and without upwind sand flux. Within the proposed model, a new definition of the saturation length is proposed based on the analogy between two damping oscillation models, and its constancy is physically interpreted and verified with wind tunnel experimental data. In comparison with the existing models, the proposed model agrees better with the measurements of the process of sand transport, thereby shedding light on the understanding of aeolian sand transport under complex circumstances.

The Role of Social Media in Earthquake Awareness and Earthquake Preparedness in Myanmar

Myanmar is an earthquake-prone country in SE Asia and all types of faulting such as strike-slip, normal, and reverse are occurring all over Myanmar territory. Apart from surface faults, the India oceanic plate is subducting obliquely beneath Burma continental plate along Sunda subduction zone. The interaction between the India plate, the Burma plate and Eurasia plate appears to be characterized by the initiation of major movements between plates switching from one to another within this tectonic region. The Sagaing Fault is a primary plate boundary between the Burma plate and Indochina plate along which most of the relative motion has occurred and will continue to occur for the geologic future. According to seismicity record in Myanmar, most of the earthquakes occurred either in the evening or at midnight or at dawn. So the people become scary because earthquake occurs without warnings. During such situation, people run immediately outside the building to the open space due to people’s survival instincts. People have anxiety which is a normal response to frightening situation. The social media interviews the earthquake researchers/ earthquake geologists why the earthquake occurs and how to protect them during earthquake. By disseminating the information on social networks, people become aware of the earthquake disaster and become focusing on effective preparedness.

Premovement inhibition can protect motor actions from interference by response‐irrelevant sensory stimulation

Suppression of corticospinal excitability is reliably observed during preparation for a range of motor actions, leading to the belief that this preparatory inhibition is a physiologically obligatory component of motor preparation. The neurophysiological function of this suppression is uncertain. We restricted the time available for participants to engage in preparation and found no evidence for preparatory inhibition. The function of preparatory inhibition can be inferred from our findings that sensory stimulation can disrupt motor output in the absence of preparatory inhibition, but enhance motor output when inhibition is present. These findings suggest preparatory inhibition may be a strategic process which acts to protect prepared actions from external interference. Our findings have significant theoretical implications for preparatory processes. Findings may also have a pragmatic benefit in that acoustic stimulation could be used therapeutically to facilitate movement, but only if the action can be prepared well in advance. Shortly before movement initiation, the corticospinal system undergoes a transient suppression. This phenomenon has been observed across a range of motor tasks, suggesting that it may be an obligatory component of movement preparation. We probed whether this was also the case when the urgency to perform a motor action was high, in a situation where little time was available to engage in preparatory processes. We controlled the urgency of an impending motor action by increasing or decreasing the foreperiod duration in an anticipatory timing task. Transcranial magnetic stimulation (TMS; experiment 1) or a loud acoustic stimulus (LAS; experiment 2) were used to examine how corticospinal and subcortical excitability were modulated during motor preparation. Preparatory inhibition of the corticospinal tract was absent when movement urgency was high, though motor actions were initiated on time. In contrast, subcortical circuits were progressively inhibited as the time to prepare increased. Interestingly, movement force and vigour were reduced by both TMS and the LAS when movement urgency was high, and enhanced when movement urgency was low. These findings indicate that preparatory inhibition may not be an obligatory component of motor preparation. The behavioural effects we observed in the absence of preparatory inhibition were induced by both TMS and the LAS, suggesting that accessory sensory stimulation may disrupt motor output when such stimulation is presented in the absence of preparatory inhibition. We conclude that preparatory inhibition may be an adaptive strategy which can serve to protect the prepared motor action from external interference.

Extending knowledge by developing a ‘slow approach’ to action research

ABSTRACT This paper is an extension of a conversation begun at the CARN 2020 Conference. It outlines how an accelerated, rushed lifestyle impacts negatively on almost every aspect of life. In education, the fast-paced life is reflected in the trend towards incessant production. This trend impacts negatively on the lives of university lecturers, teacher-educators, students and on teacher-researchers, and is reflected in the unrelenting demand for research output and performance reports. It is mirrored in the lack of time for thoughtful, critical reflection and impacts on the quality of scholarship and on professional agency. It also has negative implications for health and well-being. The contrary motion of the ‘slow’ movement formulates a sustainable alternative to the onslaught of speed. It manifests itself in the slow movement initiatives which are percolating into the fields of education and research also. The first section of this paper explains why the development of a ‘slow approach’ to action research might be sought. The second section of the paper outlines how a slow approach to action research might be envisaged in a practical manner. It outlines ideas around (i) personal awareness, (ii) intellectual awareness and (iii) relational awareness as suggested slow approaches to action research.

Investigating facilitatory versus inhibitory effects of dynamic social and non-social cues on attention in a realistic space.

This study aimed to investigate the facilitatory versus inhibitory effects of dynamic non-predictive central cues presented in a realistic environment. Realistic human-avatars initiated eye contact and then dynamically looked to the left, right or centre of a table. A moving stick served as a non-social control cue and participants localised (Experiment 1) or discriminated (Experiment 2) a contextually relevant target (teapot/teacup). The cues movement took 500 ms and stimulus onset asynchronies (SOA, 150 ms/300 ms/500 ms/1000 ms) were measured from movement initiation. Similar cuing effects were seen for the social avatar and non-social stick cue across tasks. Results showed facilitatory processes without inhibition, though there was some variation by SOA and task. This is the first time facilitatory versus inhibitory processes have been directly investigated where eye contact is initiated prior to gaze shift. These dynamic stimuli allow a better understanding of how attention might be cued in more realistic environments.

Cell specific photoswitchable agonist for reversible control of endogenous dopamine receptors

Dopamine controls diverse behaviors and their dysregulation contributes to many disorders. Our ability to understand and manipulate the function of dopamine is limited by the heterogenous nature of dopaminergic projections, the diversity of neurons that are regulated by dopamine, the varying distribution of the five dopamine receptors (DARs), and the complex dynamics of dopamine release. In order to improve our ability to specifically modulate distinct DARs, here we develop a photo-pharmacological strategy using a Membrane anchored Photoswitchable orthogonal remotely tethered agonist for the Dopamine receptor (MP-D). Our design selectively targets D1R/D5R receptor subtypes, most potently D1R (MP-D1ago), as shown in HEK293T cells. In vivo, we targeted dorsal striatal medium spiny neurons where the photo-activation of MP-D1ago increased movement initiation, although further work is required to assess the effects of MP-D1ago on neuronal function. Our method combines ligand and cell type-specificity with temporally precise and reversible activation of D1R to control specific aspects of movement. Our results provide a template for analyzing dopamine receptors.

Automatic gaze to the nose region cannot be inhibited during observation of facial expression in Eastern observers

Humans can extract a great deal of information about others very quickly. This is partly because the face automatically captures observers’ attention. Specifically, the eyes can attract overt attention. Although it has been reported that not only the eyes but also the nose can capture initial oculomotor movement in Eastern observers, its generalizability remains unknown. In this study, we applied the “don’t look” paradigm wherein participants are asked not to fixate on a specific facial region (i.e., eyes, nose, and mouth) during an emotion recognition task with upright (Experiment 1) and inverted (Experiment 2) faces. In both experiments, we found that participants were less able to inhibit the initial part of their fixations to the nose, which can be interpreted as the nose automatically capturing attention. Along with previous studies, our overt attention tends to be attracted by a part of the face, which is the nose region in Easterner observers.

Disrupting cortico-cerebellar communication impairs dexterity.

To control reaching, the nervous system must generate large changes in muscle activation to drive the limb toward the target, and must also make smaller adjustments for precise and accurate behavior. Motor cortex controls the arm through projections to diverse targets across the central nervous system, but it has been challenging to identify the roles of cortical projections to specific targets. Here, we selectively disrupt cortico-cerebellar communication in the mouse by optogenetically stimulating the pontine nuclei in a cued reaching task. This perturbation did not typically block movement initiation, but degraded the precision, accuracy, duration, or success rate of the movement. Correspondingly, cerebellar and cortical activity during movement were largely preserved, but differences in hand velocity between control and stimulation conditions predicted from neural activity were correlated with observed velocity differences. These results suggest that while the total output of motor cortex drives reaching, the cortico-cerebellar loop makes small adjustments that contribute to the successful execution of this dexterous movement.

Combining Repetition Suppression and Pattern Analysis Provides New Insights into the Role of M1 and Parietal Areas in Skilled Sequential Actions.

How does the brain change during learning? In functional magnetic resonance imaging (fMRI) studies, both multivariate pattern analysis (MVPA) and repetition suppression (RS) have been used to detect changes in neuronal representations. In the context of motor sequence learning, the two techniques have provided discrepant findings: pattern analysis showed that only premotor and parietal regions, but not primary motor cortex (M1), develop a representation of trained sequences. In contrast, RS suggested trained sequence representations in all these regions. Here, we applied both analysis techniques to a five-week finger sequence training study, in which participants executed each sequence twice before switching to a different sequence. Both RS and pattern analysis indicated learning-related changes for parietal areas, but only RS showed a difference between trained and untrained sequences in M1. A more fine-grained analysis, however, revealed that the RS effect in M1 reflects a fundamentally different process than in parietal areas. On the first execution, M1 represents especially the first finger of each sequence, likely reflecting preparatory processes. This effect dramatically reduces during the second execution. In contrast, parietal areas represent the identity of a sequence, and this representation stays relatively stable on the second execution. These results suggest that the RS effect does not reflect a trained sequence representation in M1, but rather a preparatory signal for movement initiation. More generally, our study demonstrates that across regions RS can reflect different representational changes in the neuronal population code, emphasizing the importance of combining pattern analysis and RS techniques.SIGNIFICANCE STATEMENT Previous studies using pattern analysis have suggested that primary motor cortex (M1) does not represent learnt sequential actions. However, a study using repetition suppression (RS) has reported M1 changes during motor sequence learning. Combining both techniques, we first replicate the discrepancy between them, with learning-related changes in M1 in RS, but not pattern dissimilarities. We further analyzed the representational changes with repetition, and found that the RS effects differ across regions. M1's activity represents the starting finger of the sequence, an effect that vanishes with repetition. In contrast, activity patterns in parietal areas exhibit sequence dependency, which persists with repetition. These results demonstrate the importance of combining RS and pattern analysis to understand the function of brain regions.

Thalamic input to motor cortex facilitates goal-directed action initiation

SUMMARYPrompt execution of planned motor action is essential for survival. The interactions between frontal cortical circuits and the basal ganglia are central to goal-oriented action selection and initiation.1–4 In rodents, the ventromedial thalamic nucleus (VM) is one of the critical nodes that conveys the output of the basal ganglia to the frontal cortical areas including the anterior lateral motor cortex (ALM).5–9 Recent studies showed the critical role of ALM and its interplay with the motor thalamus in preparing sensory-cued rewarded movements, specifically licking.10–12 Work in primates suggests that the basal ganglia output to the motor thalamus transmits an urgency or vigor signal,13–15 which leads to shortened reaction times and faster movement initiation. As yet, little is known about what signals are transmitted from the motor thalamus to the cortex during cued movements and how these signals contribute to movement initiation. In the present study, we employed a tactile-cued licking task in mice while monitoring reaction times of the initial lick. We found that inactivation of ALM delayed the initiation of cued licking. Two-photon Ca2+ imaging of VM axons revealed that the majority of the axon terminals in ALM were transiently active during licking. Their activity was predictive of the time of the first lick. Chemogenetic and optogenetic manipulation of VM axons in ALM indicated that VM inputs facilitate the initiation of cue-triggered and impulsive licking in trained mice. Our results suggest that VM thalamocortical inputs increase the probability and vigor of initiating planned motor responses.

A Neural Network Reveals Motoric Effects of Maternal Preconception Exposure to Nicotine on Rat Pup Behavior: A New Approach for Movement Disorders Diagnosis.

Neurodevelopmental disorders can stem from pharmacological, genetic, or environmental causes and early diagnosis is often a key to successful treatment. To improve early detection of neurological motor impairments, we developed a deep neural network for data-driven analyses. The network was applied to study the effect of maternal nicotine exposure prior to conception on 10-day-old rat pup motor behavior in an open field task. Female Long-Evans rats were administered nicotine (15 mg/L) in sweetened drinking water (1% sucralose) for seven consecutive weeks immediately prior to mating. The neural network outperformed human expert designed animal locomotion measures in distinguishing rat pups born to nicotine exposed dams vs. control dams (87 vs. 64% classification accuracy). Notably, the network discovered novel movement alterations in posture, movement initiation and a stereotypy in “warm-up” behavior (repeated movements along specific body dimensions) that were predictive of nicotine exposure. The results suggest novel findings that maternal preconception nicotine exposure delays and alters offspring motor development. Similar behavioral symptoms are associated with drug-related causes of disorders such as autism spectrum disorder and attention-deficit/hyperactivity disorder in human children. Thus, the identification of motor impairments in at-risk offspring here shows how neuronal networks can guide the development of more accurate behavioral tests to earlier diagnose symptoms of neurodevelopmental disorders in infants and children.

Altered Dynamic Information Flow through the Cortico-Basal Ganglia Pathways Mediates Parkinson's Disease Symptoms.

Parkinson’s disease (PD) is a progressive neurodegenerative disorder caused by dopamine deficiency. To elucidate network-level changes through the cortico-basal ganglia pathways in PD, we recorded neuronal activity in PD monkeys treated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine. We applied electrical stimulation to the motor cortices and examined responses in the internal (GPi) and external (GPe) segments of the globus pallidus, the output and relay nuclei of the basal ganglia, respectively. In the normal state, cortical stimulation induced a triphasic response composed of early excitation, inhibition, and late excitation in the GPi and GPe. In the PD state, cortically evoked inhibition in the GPi mediated by the cortico-striato-GPi “direct” pathway was largely diminished, whereas late excitation in the GPe mediated by the cortico-striato-GPe-subthalamo (STN)-GPe pathway was elongated. l-DOPA treatment ameliorated PD signs, particularly akinesia/bradykinesia, and normalized cortically evoked responses in both the GPi and GPe. STN blockade by muscimol injection ameliorated the motor deficit and unmasked cortically evoked inhibition in the GPi. These results suggest that information flow through the direct pathway responsible for the initiation of movements is largely reduced in PD and fails to release movements, resulting in akinesia/bradykinesia. Restoration of the information flow through the direct pathway recovers execution of voluntary movements.

Subcortical Contribution of Corticospinal Transmission during Visually Guided Switching Movements of the Arm.

In animal experiments, the indirect corticospinal tract (CST) system via cervical interneurons has been shown to mediate motor commands for online adjustment of visuomotor behaviors, such as target-reaching. However, it is still unclear whether the similar CST system functions to perform similar motor behaviors in humans. To clarify this, we investigated changes in motor-evoked potentials (MEPs) in the elbow muscles following transcranial magnetic stimulation, transcranial electrical stimulation, or cervicomedullary stimulation while participants executed target-reaching and switching movements. We found that the MEP, whether elicited cortically or subcortically, was modulated depending on the direction of the switching movements. MEP facilitation began around the onset of the switching activities in an agonist muscle. Furthermore, ulnar nerve-induced MEP facilitation, which could be mediated by presumed cervical interneuronal systems, also increased at the onset of MEP facilitation. In a patient with cortical hemianopsia who showed switching movements in the scotoma, the MEPs were facilitated just before the switching activities. Our findings suggested that CST excitation was flexibly tuned with the switching movement initiation, which could partly take place in the subcortical networks, including the presumed cervical interneuronal systems.

The invention of the writing subject in school: The studia humanitatis in the 15th-century Renaissance

ABSTRACT This article seeks to discuss the relations between reading and writing against the historical backdrop of the initial affirmation of the studia humanitatis in fifteenth-century renaissance Italy and its initial movement towards the North of Europe. It focuses first on the theory of education and learning expressed in the Treatises of four Italian humanists. These treatises were structured based on the coeval experiments undertaken by extremely famous teachers such as the Byzantine diplomat Chrysoloras (1355–1415), who is generally credited with having initiated humanist pedagogy, Gasparino Barzizza (1360–1430), in the cities of Padua and Pavia, Vittorino da Feltre (1370–1446), in Mantua, and above all, Guarino Guarini da Verona (1374–1460), in Ferrara. The action of these last three teachers led to the consolidation of the introduction into the syllabus of a large number of Latin authors, through which the study of the Greek language and literature was endowed with greater legitimacy. It also tracks the proposals of Valla (1407–1457) and Rodolph Agricola (1444–1485). The options regarding the studies and the methodologies used spread to many schools, which we today call secondary schools and universities. Although this reality is restricted in time and space, the article has the broader goal of contributing to a deeper understanding of a school culture that promotes the real development of creative writing skills among its pupils, and which therefore opposes the civilisational principle that identifies the school model in the contemporary epoch as advocating the possibility to teach everything to everybody and always based on a textbook compiled for use by the pupils.