A muscle activation model of variable stimulation frequency response and stimulation history, based on positive feedback in calcium dynamics

Otazu, Gonzalo H.; Futami, Ryoko; Hoshimiya, Nozomu

doi:10.1007/s004220000207

Cited by 13 publications

(18 citation statements)

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“…Sigmoidal relation between force level and MU firing rate (Kernell et al 1983;Macefield et al 1996;Van Zandwijk et al 1996) 2. "Catch" property in slow-type motor units (Burke et al 1970;Otazu et al 2001) 3. "Sag" property in fast-type motor units (Burke et al 1973) 4.…”

Section: Discussionmentioning

confidence: 99%

Simulation system of spinal cord motor nuclei and associated nerves and muscles, in a Web-based architecture

2008

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Section: Discussionmentioning

confidence: 99%

Simulation system of spinal cord motor nuclei and associated nerves and muscles, in a Web-based architecture

2008

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“…The dependency of L I on ⌬t (Figs. 3-5) can be explained by two competing processes: saturation of [Ca 2ϩ ] i at low ISIs, and based on Bobet and Stein (1998) (Otazu et al, 2001). …”

Section: Supralinear Temporal and Spatial Summationmentioning

confidence: 99%

Temporal and Spatial Characteristics of Vibrissa Responses to Motor Commands

Simony¹,

Bagdasarian²,

Herfst³

et al. 2010

Journal of Neuroscience

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A mechanistic description of the generation of whisker movements is essential for understanding the control of whisking and vibrissal active touch. We explore how facial-motoneuron spikes are translated, via an intrinsic muscle, to whisker movements. This is achieved by constructing, simulating, and analyzing a computational, biomechanical model of the motor plant, and by measuring spiking to movement transformations at small and large angles using high-precision whisker tracking in vivo. Our measurements revealed a supralinear summation of whisker protraction angles in response to consecutive motoneuron spikes with moderate interspike intervals (5 ms Ͻ ⌬t Ͻ 30 ms). This behavior is explained by a nonlinear transformation from intracellular changes in Ca 2ϩ concentration to muscle force. Our model predicts the following spatial constraints: (1) Contraction of a single intrinsic muscle results in movement of its two attached whiskers with different amplitudes; the relative amplitudes depend on the resting angles and on the attachment location of the intrinsic muscle on the anterior whisker. Counterintuitively, for a certain range of resting angles, activation of a single intrinsic muscle can lead to a retraction of one of its two attached whiskers. (2) When a whisker is pulled by its two adjacent muscles with similar forces, the protraction amplitude depends only weakly on the resting angle. (3) Contractions of two adjacent muscles sums up linearly for small amplitudes and supralinearly for larger amplitudes. The model provides a direct translation from motoneuron spikes to whisker movements and can serve as a building block in closed-loop motor-sensory models of active touch.

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“…2A and 2B). This result suggests that other factors inducing the force enhancement, such as nonlinear Ca 2+ dynamics in SP (Cheng et al 2013, Otazu et al 2001), passive filament components (e.g., titin,(Nishikawa et al 2012)) or active molecular modulation (e.g., phosphorylation of myosin regulatory light chain, (Sweeney et al 1993)), are likely to be involved during the relaxation phase of muscle contraction in soleus muscles.…”

Section: Discussionmentioning

confidence: 99%

An action potential-driven model of soleus muscle activation dynamics for locomotor-like movements

2015

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Objective The goal of this study was to develop a physiologically plausible, computationally robust model for the muscle activation dynamics (A(t)) under physiologically relevant excitation and movement. Approach The interaction of excitation and movement on A(t) was investigated comparing the force production between a cat soleus muscle and its Hill-type model. For capturing A(t) under excitation and movement variation, a modular modeling framework was proposed comprising of 3 compartments: (1) spikes-to-[Ca2+]; (2) [Ca2+]-to-A; and (3) A-to-force transformation. The individual signal transformations were modeled based on physiological factors so that the parameter values could be separately determined for individual modules directly based on experimental data. Main results The strong dependency of A(t) on excitation frequency and muscle length was found during both isometric and dynamically-moving contractions. The identified dependencies of A(t) under the static and dynamic conditions could be incorporated in the modular modeling framework by modulating the model parameters as a function of movement input. The new modeling approach was also applicable to cat soleus muscles producing waveforms independent of those used to set the model parameters. Significance This study provides a modeling framework for spike-driven muscle responses during movement, that is suitable not only for insights into molecular mechanisms underlying muscle behaviors but also for large scale simulations.

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A muscle activation model of variable stimulation frequency response and stimulation history, based on positive feedback in calcium dynamics

Cited by 13 publications

References 34 publications

Simulation system of spinal cord motor nuclei and associated nerves and muscles, in a Web-based architecture

Simulation system of spinal cord motor nuclei and associated nerves and muscles, in a Web-based architecture

Temporal and Spatial Characteristics of Vibrissa Responses to Motor Commands

An action potential-driven model of soleus muscle activation dynamics for locomotor-like movements

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