scholarly journals Modeling the Nonlinear Dynamic Interactions of Afferent Pathways in the Dentate Gyrus of the Hippocampus

2008 ◽  
Vol 36 (5) ◽  
pp. 852-864 ◽  
Author(s):  
Angelika Dimoka ◽  
Spiros H. Courellis ◽  
Vasilis Z. Marmarelis ◽  
Theodore W. Berger
Author(s):  
Geoffrey Ngene ◽  
Jinghua Wang ◽  
M. Kabir Hassan ◽  
Ivan Julio ◽  
Jung-Suk Yu

2013 ◽  
Vol 20 (6) ◽  
pp. 1093-1101 ◽  
Author(s):  
Aline Souza de Paula ◽  
José Manoel Balthazar ◽  
Jorge Luis Palacios Felix

This paper presents a nonlinear dynamic analysis of a flexible portal frame subjected to support excitation, which is provided by an electro-dynamical shaker. The main goal of this study is to investigate the dynamic interactions between a flexible portal frame and a nonlinear electrical support excitation. The numerical analysis shows a complex behavior of the system, which can be observed by phase spaces, Poincaré sections and bifurcation diagrams.


2003 ◽  
Vol 89 (6) ◽  
pp. 3018-3028 ◽  
Author(s):  
Charles J. Frazier ◽  
Ben W. Strowbridge ◽  
Roger L. Papke

Although the dentate gyrus is one of the primary targets of septo-hippocampal cholinergic afferents, relatively little is known about the cholinergic physiology of neurons in the area. By combining whole cell patch-clamp recording with brief local application of exogenous agonists in horizontal slices, we found that there is robust expression of functional somatic α7-containing nicotinic acetylcholine receptors (nAChRs) on molecular layer interneurons, hilar interneurons, and the glutamatergic mossy cells of the dentate hilus. In contrast, the principal neurons of the dentate gyrus, the granule cells, are generally unresponsive to focal somatic or dendritic application of ACh in the presence of atropine. We also demonstrate that cholinergic activation of α7-containing nAChRs on the subgranular interneurons of the hilus can produce methyllycaconitine-sensitive GABAergic inhibitory postsynaptic currents (IPSCs) in nearby granule cells and enhance the amplitude of an electrically evoked monosynaptic IPSC. Further, activation of α7-containing nAChRs on subgranular interneurons that is timed to coincide with synaptic release of glutamate onto these cells will enhance the functional inhibition of granule cells. These findings suggest that a complex interplay between glutamatergic afferents from the entorhinal cortex and cholinergic afferents from the medial septum could be involved in the normal regulation of granule cell function. Such a relationship between these two afferent pathways could be highly relevant to the study of both age-related memory dysfunction and disorders involving regulation of excitability, such as temporal lobe epilepsy.


2008 ◽  
Vol 35 (5-6) ◽  
pp. 511-522 ◽  
Author(s):  
Dong-Soo Hur ◽  
Chang-Hoon Kim ◽  
Do-Sam Kim ◽  
Jong-Sung Yoon

2017 ◽  
Author(s):  
Geoff Boeing

Complexity theory has become a popular frame for conceptualizing and analyzing cities. The theory proposes that certain large systems are characterized by the nonlinear, dynamic interactions of their many constituent parts. These systems then behave in novel and unpredictable ways—ways that cannot be divined by examining the components of the system. Complexity theory problematizes traditional reductionist, linear methods of scientifically analyzing and predicting cities. It also opens up a new world of scholarship to researchers keen to formulate new kinds of sciences that take complexity into account. These attempts usually follow Kuhn’s theory of paradigm shifts: new evidence and modes of thinking undermine an established science, and a new science emerges to replace it.


2020 ◽  
Vol 43 (4) ◽  
pp. 25-40
Author(s):  
Tom Mudd ◽  
Simon Holland ◽  
Paul Mulholland

Nonlinear dynamic processes are fundamental to the behavior of acoustic musical instruments, as is well explored in the case of sound production. Such processes may have profound and under-explored implications for how musicians interact with instruments, however. Although nonlinear dynamic processes are ubiquitous in acoustic instruments, they are present in digital musical tools only if explicitly implemented. Thus, an important resource with potentially major effects on how musicians interact with acoustic instruments is typically absent in the way musicians interact with digital instruments. Twenty-four interviews with free-improvising musicians were conducted to explore the role that nonlinear dynamics play in the participants' musical practices and to understand how such processes can afford distinctive methods of creative exploration. Thematic analysis of the interview data is used to demonstrate the potential for nonlinear dynamic processes to provide repeatable, learnable, controllable, and explorable interactions, and to establish a vocabulary for exploring nonlinear dynamic interactions. Two related approaches to engaging with nonlinear dynamic behaviors are elaborated: edge-like interaction, which involves the creative use of critical thresholds; and deep exploration, which involves exploring the virtually unlimited subtleties of a small control region. The elaboration of these approaches provides an important bridge that connects the concrete descriptions of interaction in musical practices, on the one hand, to the more-abstract mathematical formulation of nonlinear dynamic systems, on the other.


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