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1.
Glia ; 69(2): 392-412, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32910475

RESUMO

Mitochondria are dynamic organelles that produce energy and molecular precursors that are essential for myelin synthesis. Unlike in neurons, mitochondria in oligodendrocytes increase intracellular movement in response to glutamatergic activation and are more susceptible to oxidative stress than in astrocytes or microglia. The signaling pathways that regulate these cell type-specific mitochondrial responses in oligodendrocytes are not understood. Here, we visualized mitochondria migrating through thin cytoplasmic channels crossing myelin basic protein-positive compacted membranes and localized within paranodal loop cytoplasm. We hypothesized that local extracellular enrichment of netrin-1 might regulate the recruitment and function of paranodal proteins and organelles, including mitochondria. We identified rapid recruitment of mitochondria and paranodal proteins, including neurofascin 155 (NF155) and the netrin receptor deleted in colorectal carcinoma (DCC), to sites of contact between oligodendrocytes and netrin-1-coated microbeads in vitro. We provide evidence that Src-family kinase activation and Rho-associated protein kinase (ROCK) inhibition downstream of netrin-1 induces mitochondrial elongation, hyperpolarization of the mitochondrial inner membrane, and increases glycolysis. Our findings identify a signaling mechanism in oligodendrocytes that is sufficient to locally recruit paranodal proteins and regulate the subcellular localization, morphology, and function of mitochondria.

2.
Entropy (Basel) ; 22(11)2020 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-33287069

RESUMO

Self-organization in nonequilibrium systems has been known for over 50 years. Under nonequilibrium conditions, the state of a system can become unstable and a transition to an organized structure can occur. Such structures include oscillating chemical reactions and spatiotemporal patterns in chemical and other systems. Because entropy and free-energy dissipating irreversible processes generate and maintain these structures, these have been called dissipative structures. Our recent research revealed that some of these structures exhibit organism-like behavior, reinforcing the earlier expectation that the study of dissipative structures will provide insights into the nature of organisms and their origin. In this article, we summarize our study of organism-like behavior in electrically and chemically driven systems. The highly complex behavior of these systems shows the time evolution to states of higher entropy production. Using these systems as an example, we present some concepts that give us an understanding of biological organisms and their evolution.

3.
Ann N Y Acad Sci ; 2020 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-33336809

RESUMO

It is commonly understood that hand gesture and speech coordination in humans is culturally and cognitively acquired, rather than having a biological basis. Recently, however, the biomechanical physical coupling of arm movements to speech vocalization has been studied in steady-state vocalization and monosyllabic utterances, where forces produced during gesturing are transferred onto the tensioned body, leading to changes in respiratory-related activity and thereby affecting vocalization F0 and intensity. In the current experiment (n = 37), we extend this previous line of work to show that gesture-speech physics also impacts fluent speech. Compared with nonmovement, participants who are producing fluent self-formulated speech while rhythmically moving their limbs demonstrate heightened F0 and amplitude envelope, and such effects are more pronounced for higher-impulse arm versus lower-impulse wrist movement. We replicate that acoustic peaks arise especially during moments of peak impulse (i.e., the beat) of the movement, namely around deceleration phases of the movement. Finally, higher deceleration rates of higher-mass arm movements were related to higher peaks in acoustics. These results confirm a role for physical impulses of gesture affecting the speech system. We discuss the implications of gesture-speech physics for understanding of the emergence of communicative gesture, both ontogenetically and phylogenetically.

4.
J Acoust Soc Am ; 148(3): 1231, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33003900

RESUMO

Expressive moments in communicative hand gestures often align with emphatic stress in speech. It has recently been found that acoustic markers of emphatic stress arise naturally during steady-state phonation when upper-limb movements impart physical impulses on the body, most likely affecting acoustics via respiratory activity. In this confirmatory study, participants (N = 29) repeatedly uttered consonant-vowel (/pa/) mono-syllables while moving in particular phase relations with speech, or not moving the upper limbs. This study shows that respiration-related activity is affected by (especially high-impulse) gesturing when vocalizations occur near peaks in physical impulse. This study further shows that gesture-induced moments of bodily impulses increase the amplitude envelope of speech, while not similarly affecting the Fundamental Frequency (F0). Finally, tight relations between respiration-related activity and vocalization were observed, even in the absence of movement, but even more so when upper-limb movement is present. The current findings expand a developing line of research showing that speech is modulated by functional biomechanical linkages between hand gestures and the respiratory system. This identification of gesture-speech biomechanics promises to provide an alternative phylogenetic, ontogenetic, and mechanistic explanatory route of why communicative upper limb movements co-occur with speech in humans.

6.
Proc Natl Acad Sci U S A ; 117(21): 11364-11367, 2020 05 26.
Artigo em Inglês | MEDLINE | ID: mdl-32393618

RESUMO

We show that the human voice has complex acoustic qualities that are directly coupled to peripheral musculoskeletal tensioning of the body, such as subtle wrist movements. In this study, human vocalizers produced a steady-state vocalization while rhythmically moving the wrist or the arm at different tempos. Although listeners could only hear and not see the vocalizer, they were able to completely synchronize their own rhythmic wrist or arm movement with the movement of the vocalizer which they perceived in the voice acoustics. This study corroborates recent evidence suggesting that the human voice is constrained by bodily tensioning affecting the respiratory-vocal system. The current results show that the human voice contains a bodily imprint that is directly informative for the interpersonal perception of another's dynamic physical states.


Assuntos
Extremidade Superior/fisiologia , Voz/fisiologia , Adulto , Percepção Auditiva , Feminino , Audição/fisiologia , Humanos , Masculino , Atividade Motora/fisiologia , Experimentação Humana não Terapêutica , Punho/fisiologia
7.
Nonlinear Dynamics Psychol Life Sci ; 24(2): 143-157, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32248885

RESUMO

Stimulus-response compatibility effects illustrate the mutual depen-dence of perception and action processes. Ellis and Tucker (2000) showed that object identification was facilitated when the response required a grip that was compatible with the stimulus. In the current study, we extend grip-compatibility effects to perception of the Necker cube. Participants reported the perceived orientation of a Necker cube by orienting a hand-held cube into a compatible or an incompatible position. Participants in the incompatible condition were quickly attracted to the FRB (front-side right bottom) percept, consistent with previous work. However, participants in the compatible condition showed an extended period of metastability, switching between the two perceptual states about equally. A second experiment replicated these results and showed that a control condition in which responses were made with a key press produced intermediate levels of metastability. These results are interpreted in terms of the dynamics of bistable perception.


Assuntos
Força da Mão , Orientação , Humanos , Orientação Espacial , Percepção Visual
8.
J Exp Psychol Gen ; 149(2): 391-404, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31368760

RESUMO

The phenomenon of gesture-speech synchrony involves tight coupling of prosodic contrasts in gesture movement (e.g., peak velocity) and speech (e.g., peaks in fundamental frequency; F0). Gesture-speech synchrony has been understood as completely governed by sophisticated neural-cognitive mechanisms. However, gesture-speech synchrony may have its original basis in the resonating forces that travel through the body. In the current preregistered study, movements with high physical impact affected phonation in line with gesture-speech synchrony as observed in natural contexts. Rhythmic beating of the arms entrained phonation acoustics (F0 and the amplitude envelope). Such effects were absent for a condition with low-impetus movements (wrist movements) and a condition without movement. Further, movement-phonation synchrony was more pronounced when participants were standing as opposed to sitting, indicating a mediating role for postural stability. We conclude that gesture-speech synchrony has a biomechanical basis, which will have implications for our cognitive, ontogenetic, and phylogenetic understanding of multimodal language. (PsycINFO Database Record (c) 2020 APA, all rights reserved).


Assuntos
Gestos , Fala/fisiologia , Adulto , Fenômenos Biomecânicos/fisiologia , Feminino , Humanos , Masculino , Física , Adulto Jovem
9.
Behav Res Methods ; 52(2): 723-740, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31659689

RESUMO

There is increasing evidence that hand gestures and speech synchronize their activity on multiple dimensions and timescales. For example, gesture's kinematic peaks (e.g., maximum speed) are coupled with prosodic markers in speech. Such coupling operates on very short timescales at the level of syllables (200 ms), and therefore requires high-resolution measurement of gesture kinematics and speech acoustics. High-resolution speech analysis is common for gesture studies, given that field's classic ties with (psycho)linguistics. However, the field has lagged behind in the objective study of gesture kinematics (e.g., as compared to research on instrumental action). Often kinematic peaks in gesture are measured by eye, where a "moment of maximum effort" is determined by several raters. In the present article, we provide a tutorial on more efficient methods to quantify the temporal properties of gesture kinematics, in which we focus on common challenges and possible solutions that come with the complexities of studying multimodal language. We further introduce and compare, using an actual gesture dataset (392 gesture events), the performance of two video-based motion-tracking methods (deep learning vs. pixel change) against a high-performance wired motion-tracking system (Polhemus Liberty). We show that the videography methods perform well in the temporal estimation of kinematic peaks, and thus provide a cheap alternative to expensive motion-tracking systems. We hope that the present article incites gesture researchers to embark on the widespread objective study of gesture kinematics and their relation to speech.

10.
Int Ophthalmol ; 40(3): 609-616, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31768813

RESUMO

PURPOSE: To determine predictors of best-corrected postoperative visual acuity (VA) in patients who underwent surgical intervention for macula-off rhegmatogenous retinal detachment. MATERIALS AND METHODS: Primary macula-off retinal detachments from the University of Colorado Primary Rhegmatogenous Retinal Detachment Database (2012-2017) were reviewed. The primary outcome measure was a postoperative VA of 20/40 or better at least 6 months after surgery. Patient demographics, medical history, duration of central vision loss before surgery, examination findings, operative technique, and postoperative findings were analyzed as possible predictors of postoperative visual recovery to 20/40 or better. Chi-square or Fisher's exact test was used to compare categorical variables, and Wilcoxon rank sum test was used for continuous variables. A multivariable logistic regression analysis was used to determine the adjusted odds ratios and 95% confidence intervals for variables that were significant in the univariable analyses. Statistical significance was set at p < 0.05. RESULTS: One hundred thirty-one patients met inclusion criteria. Eighty-one (61.8%) patients achieved a postoperative VA of 20/40 or better 6 or more months after surgery. Patients with a single retinal break were more likely than patients with more than one break to reach a postoperative VA of 20/40 or better (76.9% vs. 55.4%, p = 0.021). Patients with a better preoperative logMAR VA had better postoperative VA (p = 0.021). Duration of central vision loss prior to surgical repair was not related to final postoperative VA in this particular study. CONCLUSION: Postoperative recovery of visual acuity to 20/40 or better was significantly more common in patients with a single retinal break as well as in patients with better preoperative visual acuity. Duration of central vision loss prior to surgical repair was not significantly associated with postoperative VA.

11.
Langmuir ; 35(34): 11066-11070, 2019 08 27.
Artigo em Inglês | MEDLINE | ID: mdl-31381346

RESUMO

From flocks of birds and sheep to colonies of bacteria, complex patterns and self-motion are found in all hierarchies of nature. Artificial nonliving systems provide useful insight, since living systems are complicated and may involve cognitive issues not found in nonliving matter. Herein, we report naturally flocking irregularly shaped benzoquinone (BQ) particles on the air-water interface that cross a gate. In this open system designed with absence of external control, the particle flock moves by Marangoni "surfing" driven by slow dissolution of weakly surface active BQ postulated to create inhomogeneous interfacial tension fields. The particle flocks move collectively through a gate placed in the air-water interface to the side that has higher interfacial tension. Position-sensitive surface tension measurements used for the first time in a multiparticle Marangoni motion system show unequivocally that flock motion and gate crossing proceed to areas of slightly higher interfacial tension. Flock crossing is accompanied by a low-high differential interfacial tension change from one side of the gate to the other, with the flock moving to the side with higher interfacial tension. Thus, the flocks move because they are foraging for interfacial free energy.

12.
PLoS One ; 14(5): e0217305, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31141547

RESUMO

Physical systems open to a flow of energy can exhibit spontaneous symmetry breaking and self-organization. These nonequilibrium self-organized systems are known as dissipative structures. We study the oscillatory mode of an electrically driven dissipative structure. Our system consists of aluminum beads in shallow oil, which, when subjected to a high voltage, self-organize into connected 'tree' structures. The tree structures serve as pathways for the conduction of charge to ground. This system shows a variety of spatio-temporal behaviors, such as oscillating movement of the tree structures. Utilizing a dynamical systems model of the electromagnetic phenomena, we explore a potential mechanism underlying the system's behavior and use the model to make additional empirical predictions. The model reproduces the oscillatory behavior observed in the real system, and the behavior of the real system is consistent with predictions from the model under various constraints. From the empirical results and the mathematical model, we observe a tendency for the system to select modes of behavior with increased dissipation, or higher rates of entropy production, in accord with the proposed Maximum Entropy Production (MEP) Principle.


Assuntos
Fenômenos Eletromagnéticos , Entropia , Modelos Biológicos , Modelos Teóricos
13.
J Phys Chem B ; 123(17): 3832-3840, 2019 05 02.
Artigo em Inglês | MEDLINE | ID: mdl-30958003

RESUMO

Collective self-motion of particulate systems provides novel opportunities for developing flocking and sensing functions from seemingly inanimate objects. In this paper, we report videos documenting spontaneous collective flocking of multiple irregularly shaped macroscopic benzoquinone (BQ) particles at the air-water interface. Self-propulsion occurs due to the Gibbs-Marangoni effect surface tension gradients generated by the BQ particles. The air-water interface develops inhomogeneous interfacial tension fields created by differential dissolution at points and edges of BQ particles, causing interfacial tension variations along the solid-liquid-air interfaces. Responses of irregularly shaped BQ particles to these driving forces do not result in random motion but lead to a cooperative hydrodynamic flocking. Curiously, the flocking behavior was very evident for irregularly shaped particles but not observed for symmetric circular BQ disks. The flock responds to changes in its local environment as it forages for interfacial free energy. It exhibits warm and cool thermotaxis and thus can sense local temperature changes. Also, though a single magnetic bead is not confined to a part of the Petri dish by an applied magnetic field, when this magnetic bead is a member of a flock in which all of the other beads are not magnetic, the flock as a whole moves and hovers around the region where the field is maximum. In other words, the magnetic bead becomes a kind of "sensor" for the flock to respond to a magnetic field, the response being a drift in the direction of the field.

14.
Cogn Sci ; 43(3): e12721, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30900288

RESUMO

Gesture-speech synchrony re-stabilizes when hand movement or speech is disrupted by a delayed feedback manipulation, suggesting strong bidirectional coupling between gesture and speech. Yet it has also been argued from case studies in perceptual-motor pathology that hand gestures are a special kind of action that does not require closed-loop re-afferent feedback to maintain synchrony with speech. In the current pre-registered within-subject study, we used motion tracking to conceptually replicate McNeill's () classic study on gesture-speech synchrony under normal and 150 ms delayed auditory feedback of speech conditions (NO DAF vs. DAF). Consistent with, and extending McNeill's original results, we obtain evidence that (a) gesture-speech synchrony is more stable under DAF versus NO DAF (i.e., increased coupling effect), (b) that gesture and speech variably entrain to the external auditory delay as indicated by a consistent shift in gesture-speech synchrony offsets (i.e., entrainment effect), and (c) that the coupling effect and the entrainment effect are co-dependent. We suggest, therefore, that gesture-speech synchrony provides a way for the cognitive system to stabilize rhythmic activity under interfering conditions.


Assuntos
Percepção Auditiva/fisiologia , Retroalimentação Sensorial/fisiologia , Gestos , Fala , Adolescente , Fenômenos Biomecânicos/fisiologia , Feminino , Humanos , Masculino , Fatores de Tempo , Adulto Jovem
15.
Hum Mov Sci ; 59: 96-111, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29627663

RESUMO

Collective behavior can be defined as the ability of humans to coordinate with others through a complex environment. Sports offer exquisite examples of this dynamic interplay, requiring decision making and other perceptual-cognitive skills to adjust individual decisions to the team self-organization and vice versa. Considering players of a team as periodic phase oscillators, synchrony analyses can be used to model the coordination of a team. Nonetheless, a main limitation of current models is that collective behavior is context independent. In other words, players on a team can be highly synchronized without this corresponding to a meaningful coordination dynamics relevant to the context of the game. Considering these issues, the aim of this study was to develop a method of analysis sensitive to the context for evidence-based measures of collective behavior.


Assuntos
Comportamento Cooperativo , Relações Interpessoais , Futebol/psicologia , Adolescente , Adulto , Análise por Conglomerados , Tomada de Decisões/fisiologia , Humanos , Masculino , Futebol/fisiologia , Adulto Jovem
16.
J Sport Health Sci ; 5(1): 25-34, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30356924

RESUMO

Background: Interpersonal coordination is an essential aspect of daily life, and crucial to performance in cooperative and competitive team sports. While empirical research has investigated interpersonal coordination using a wide variety of analytical tools and frameworks, to date very few studies have employed multifractal techniques to study the nature of interpersonal coordination across multiple spatiotemporal scales. In the present study we address this gap. Methods: We investigated the dynamics of a simple dyadic interpersonal coordination task where each participant manually controlled a virtual object in relation to that of his or her partner. We tested whether the resulting hand-movement time series exhibits multi-scale properties and whether those properties are associated with successful performance. Results: Using the formalism of multifractals, we show that the performance on the coordination task is strongly multi-scale, and that the multi-scale properties appear to arise from interaction-dominant dynamics. Further, we find that the measure of across-scale interactions, multifractal spectrum width, predicts successful performance at the level of the dyad. Conclusion: The results are discussed with respect to the implications of multifractals and interaction-dominance for understanding control in an interpersonal context.

17.
Phys Chem Chem Phys ; 17(44): 29891-8, 2015 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-26488440

RESUMO

Self-motion of physical-chemical systems is a promising avenue for studying and developing mechanical functions with inanimate systems. In this paper, we investigate spontaneous motion of collections of solid macroscopic benzoquinone (BQ) disks at the air-water interface without intervention of chemical reactions. The BQ particles slowly dissolve and create heterogeneous interfacial tension fields on the water surface that drive the motion. Spontaneous, continuous locomotion was observed between multiple BQ particles, along with coupling, collisions, cycling and collective foraging for interfacial free energy. Analysis of the motion suggests co-operative behavior depends strongly on particle shape.


Assuntos
Ar , Benzoquinonas/química , Água , Solubilidade
18.
J Exp Psychol Hum Percept Perform ; 40(6): 2289-309, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25328996

RESUMO

Intermodal integration required for perceptual learning tasks is rife with individual differences. Participants vary in how they use perceptual information to one modality. One participant alone might change her own response over time. Participants vary further in their use of feedback through one modality to inform another modality. Two experiments test the general hypothesis that perceptual-motor fluctuations reveal both information use within modality and coordination among modalities. Experiment 1 focuses on perceptual learning in dynamic touch, in which participants use exploratory hand-wielding of unseen objects to make visually guided length judgments and use visual feedback to rescale their judgments of the same mechanical information. Previous research found that the degree of fractal temporal scaling (i.e., "fractality") in hand-wielding moderates the use of mechanical information. Experiment 1 shows that head-sway fractality moderates the use of visual information. Further, experience with feedback increases head-sway fractality and prolongs its effect on later hand-wielding fractality. Experiment 2 replicates effects of head-sway fractality moderating use of visual information in a purely visual-judgment task. Together, these findings suggest that fractal fluctuations may provide a modal-general window onto not just how participants use perceptual information but also how well they may integrate information among different modalities.


Assuntos
Retroalimentação Sensorial , Movimentos da Cabeça , Julgamento , Reconhecimento Visual de Modelos , Desempenho Psicomotor , Estereognose , Adolescente , Atenção , Humanos , Individualidade , Masculino , Orientação , Percepção de Tamanho , Adulto Jovem
19.
Hum Mov Sci ; 32(1): 91-105, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23317679

RESUMO

The present work documents reanalysis of previous research by Priplata and colleagues (Priplata et al., 2002) into the effects of subthreshold vibratory stimulation to the plantar surface of the foot on postural stability during quiet standing. In stochastic resonance, stimulating a nonlinear system with noise can promote system stability. Stochastic resonance has been proposed to have clinical applications as an intervention that might help to stabilize posture. Insoles designed to stimulate the plantar surface of the foot with uncorrelated white-noise fluctuations have been shown to reduce a number of standard measures of postural variability. An important remaining concern is that the efficacy of stochastic-resonance applications is subject to strong individual differences. Our reanalysis of data from Priplata et al.'s original study provides evidence that effects of uncorrelated fluctuations in subthreshold vibratory stimulation are moderated by temporally correlated fluctuations in postural sway. We suggest how future development might capitalize on this finding to fine-tune existing stochastic-resonance applications to posture.


Assuntos
Envelhecimento/fisiologia , Equilíbrio Postural/fisiologia , Suporte de Carga/fisiologia , Adulto , Idoso , Fenômenos Biomecânicos/fisiologia , Feminino , Humanos , Individualidade , Masculino , Dinâmica não Linear , Valores de Referência , Estatística como Assunto , Processos Estocásticos , Estimulação Subliminar , Vibração
20.
Ann Biomed Eng ; 41(8): 1625-34, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23188561

RESUMO

Movement science has traditionally understood high-dimensional fluctuations as either antithetical or irrelevant to low-dimensional control. However, fluctuations incident to changeful, sometimes unpredictable stimulation must somehow reshape low-dimensional aspects of control through perception. The movement system's fluctuations may reflect cascade dynamics in which many-sized events interact nonlinearly across many scales. Cascades yield fractal fluctuations, and fractality of fluctuations may provide a window on the interactions across scale supporting perceptual processes. To test these ideas, we asked adult human participants to judge whole or partial length for unseen rods (with and without added masses). The participants' only experience with the objects came from supporting them across their shoulders during quiet standing. First, the degree of fractal temporal correlations in trial-by-trial series of planar Euclidean displacements in center of pressure (COP) significantly improved prediction of subsequent trial-by-trial judgments, above and beyond prediction by traditional predictors of haptic perception and conventional measures of COP variability. Second, comparison with linear surrogate data indicated the presence of nonlinear interactions across scale in these time series. These results demonstrate that high-dimensional fluctuations may serve a crucial role in the cascade dynamics supporting apparently low-dimensional control strategies.


Assuntos
Adaptação Fisiológica/fisiologia , Modelos Biológicos , Movimento/fisiologia , Equilíbrio Postural/fisiologia , Postura/fisiologia , Desempenho Psicomotor/fisiologia , Percepção do Tato/fisiologia , Simulação por Computador , Feminino , Fractais , Humanos , Masculino , Estresse Mecânico , Adulto Jovem
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