Crossbridge Cycling and Cooperative Recruitment Can Account for Oscillatory Dynamics of Constantly Activated Heart

Author(s):  
Kenneth B. Campbell ◽  
Robert D. Kirkpatrick
Keyword(s):  
2018 ◽  
Vol 21 (6) ◽  
pp. 411-419 ◽  
Author(s):  
Conghua Wang ◽  
Fang Yan ◽  
Yuan Zhang ◽  
Haihong Liu ◽  
Linghai Zhang

Aims and Objective: A large number of experimental evidences report that the oscillatory dynamics of p53 would regulate the cell fate decisions. Moreover, multiple time delays are ubiquitous in gene expression which have been demonstrated to lead to important consequences on dynamics of genetic networks. Although delay-driven sustained oscillation in p53-based networks is commonplace, the precise roles of such delays during the processes are not completely known. Method: Herein, an integrated model with five basic components and two time delays for the network is developed. Using such time delays as the bifurcation parameter, the existence of Hopf bifurcation is given by analyzing the relevant characteristic equations. Moreover, the effects of such time delays are studied and the expression levels of the main components of the system are compared when taking different parameters and time delays. Result and Conclusion: The above theoretical results indicated that the transcriptional and translational delays can induce oscillation by undergoing a super-critical Hopf bifurcation. More interestingly, the length of these delays can control the amplitude and period of the oscillation. Furthermore, a certain range of model parameter values is essential for oscillation. Finally, we illustrated the main results in detail through numerical simulations.


2021 ◽  
Vol 3 (3) ◽  
Author(s):  
Satish Kumar Tiwari ◽  
Ravikant Singh ◽  
Nilesh Kumar Thakur

AbstractWe propose a model for tropic interaction among the infochemical-producing phytoplankton and non-info chemical-producing phytoplankton and microzooplankton. Volatile information-conveying chemicals (infochemicals) released by phytoplankton play an important role in the food webs of marine ecosystems. Microzooplankton is an ecologically important grazer of phytoplankton for coexistence of a large number of phytoplankton species. Here, we discuss how information transferred by dimethyl sulfide shapes the interaction of phytoplankton. Phytoplankton deterrents may lead to propagation of IPP bloom. The interaction between IPP and microzooplankton follows the Beddington–DeAngelis-type functional response. Analytically, we discuss boundedness, stability and Turing instability of the model system. We perform numerical simulation for temporal (ODE model) as well as a spatial model system. Our numerical investigation shows that microzooplankton grazing refuse of IPP leads to oscillatory dynamics. Increasing diffusion coefficient of microzooplankton shows Turing instability. Time evolution also plays an important role in the stability of system dynamics. The results obtained in this paper are useful to understand the dominance of algal bloom in coastal and estuarine ecosystem.


1989 ◽  
Vol 77 (4) ◽  
pp. 1135 ◽  
Author(s):  
P. H. Thrall ◽  
S. W. Pacala ◽  
J. A. Silander

Author(s):  
Christina M. Vanden Bosch der Nederlanden ◽  
J. Eric T. Taylor ◽  
Jessica A. Grahn

To understand and enjoy music, it is important to be able to hear the beat and move your body to the rhythm. However, impaired rhythm processing has a broader impact on perception and cognition beyond music-specific tasks. We also experience rhythms in our everyday interactions, through the lip and jaw movements of watching someone speak, the syllabic structure of words on the radio, and in the movements of our limbs when we walk. Impairments in the ability to perceive and produce rhythms are related to poor language outcomes, such as dyslexia, and they can provide an index of a primary symptom in movement disorders, such as Parkinson’s disease. The chapter summarizes a growing body of literature examining the neural underpinnings of rhythm perception and production. It highlights the importance of auditory-motor relationships in finding and producing a beat in music by reviewing evidence from a number of methodologies. These approaches illustrate how rhythmic auditory information capitalizes on auditory-motor interactions to influence motor excitability, and how beat perception emerges as a function of nonlinear oscillatory dynamics of the brain. Together these studies highlight the important role of rhythm in human development, evolutionary comparisons, multi-modal perception, mirror neurons, language processing, and music.


2018 ◽  
Vol 40 (3) ◽  
pp. 729-740 ◽  
Author(s):  
Timothy J. McDermott ◽  
Alex I. Wiesman ◽  
Mackenzie S. Mills ◽  
Rachel K. Spooner ◽  
Nathan M. Coolidge ◽  
...  

2018 ◽  
Vol 30 (4) ◽  
pp. 594-602 ◽  
Author(s):  
Giovanni Mento ◽  
Duncan E. Astle ◽  
Gaia Scerif

Temporal orienting of attention operates by biasing the allocation of cognitive and motor resources in specific moments in time, resulting in the improved processing of information from expected compared with unexpected targets. Recent findings have shown that temporal orienting operates relatively early across development, suggesting that this attentional mechanism plays a core role for human cognition. However, the exact neurophysiological mechanisms allowing children to attune their attention over time are not well understood. In this study, we presented 8- to 12-year-old children with a temporal cueing task designed to test (1) whether anticipatory oscillatory dynamics predict children's behavioral performance on a trial-by-trial basis and (2) whether anticipatory oscillatory neural activity may be supported by cross-frequency phase–amplitude coupling as previously shown in adults. Crucially, we found that, similar to what has been reported in adults, children's ongoing beta rhythm was strongly coupled with their theta rhythm and that the strength of this coupling distinguished validly cued temporal intervals, relative to neutral cued trials. In addition, in long trials, there was an inverse correlation between oscillatory beta power and children's trial-by-trial reaction, consistent with oscillatory beta power reflecting better response preparation. These findings provide the first experimental evidence that temporal attention in children operates by exploiting oscillatory mechanism.


Sign in / Sign up

Export Citation Format

Share Document