A complex biological system: the fly's visual module

Baptista, Murilo S.; Almeida, Lírio Onofre Baptista de; Slaets, Jan Frans Willem; Köberle, R.; Grebogi, Celso

doi:10.1098/rsta.2007.2093

Cited by 5 publications

(3 citation statements)

References 17 publications

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“…We illustrate our ideas in a relevant type of excitable active channel, the chaotic neural channel [30,31,32], formed by a network of electrically connected Hindmarsh-Rose (HR) neuron models [33]. This network possesses both characteristics of the periodic and chaotic channels, since it has both positive and negative Lyapunov exponents.…”

Section: The Neuron Channelmentioning

confidence: 99%

Transmission of information in active networks

Baptista

Kurths

2008

Phys. Rev. E

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Shannon's capacity theorem is the main concept behind the theory of communication. It says that if the amount of information contained in a signal is smaller than the channel capacity of a physical media of communication, it can be transmitted with arbitrarily small probability of error. This theorem is usually applicable to ideal channels of communication in which the information to be transmitted does not alter the passive characteristics of the channel that basically tries to reproduce the source of information. For an active channel, a network formed by elements that are dynamical systems (such as neurons, chaotic or periodic oscillators), it is unclear if such theorem is applicable, once an active channel can adapt to the input of a signal, altering its capacity. To shed light into this matter, we show, among other results, how to calculate the information capacity of an active channel of communication. Then, we show that the channel capacity depends on whether the active channel is self-excitable or not and that, contrary to a current belief, desynchronization can provide an environment in which large amounts of information can be transmitted in a channel that is self-excitable. An interesting case of a self-excitable active channel is a network of electrically connected Hindmarsh-Rose chaotic neurons.

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Section: The Neuron Channelmentioning

confidence: 99%

Transmission of information in active networks

Baptista

Kurths

2008

Phys. Rev. E

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“…6). Indeed, even physiological processes are laced with fractal structures and chaos [Free et al, 1996; Kedzia et al, 2002; Kido et al, 2003; Tsuda et al, 2004; Tsuda and Fujii, 2007; Baptista et al, 2008]. Such fractal structures have an obvious advantage for living beings, because they represent a splendid means for optimization, achieving the most efficient structures for a number of goals in the most economic way.…”

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confidence: 99%

In vivo performance of selective electron beam‐melted Ti‐6Al‐4V structures

Ponader

Wilmowsky

Widenmayer

et al. 2009

J Biomedical Materials Res

177

111

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Highly porous titanium structures are widely used for maxillofacial and orthopedic surgery because of their excellent mechanical properties similar to those of human bone and their facilitation of bone ingrowth. In contrast to common methods, the generation of porous titaniumproducts by selective electron beam melting (SEBM), an additive manufacturing technology, overcomes difficulties concerning the extreme chemical affinity of liquid titanium to atmospheric gases which consequently leads to strongly reduced ductility of the metal. The purpose of this study was to assess the suitability of a smooth compact and a porous Ti-6Al-4V structure directly produced by the SEBM process as scaffolds for bone formation. SEBM-processed titanium implants were placed into defects in the frontal skull of 15 domestic pigs. To evaluate the direct contact between bone and implant surfaces and to assess the ingrowth of osseous tissue into the porous structure, microradiographs and histomorphometric analyses were performed 14, 30, and 60 days after surgery. Bone ingrowth increased significantly during the period of this study. After 14 days the most outer regions of the implants were already filled with newly formed bone tissue (around 14%). After 30 days the bone volume inside the implants reached almost 30% and after 60 days abundant bone formation inside the implants attained 46%. During the study only scarce bone-implant contact was found around all implants, which did not exceed 9% around compact specimens and 6% around porous specimens after 60 days. This work demonstrates that highly porous titanium implants with excellent interconnectivity manufactured using the SEBM method are suitable scaffolds for bone ingrowth. This technique is a good candidate for orthopedic and maxillofacial applications.

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“…We emphasize that input event periods employed during this test were well below the minimum intervals between spikes (refractory period) attainable by a typical neuron. For example, in Chrysomya megacephala's H1 neuron this minimum interval is 2 ms [20].…”

Section: Experimental Validationmentioning

confidence: 99%

Modular Acquisition and Stimulation System for Timestamp-Driven Neuroscience Experiments

Matias

Guariento

Almeida

et al. 2015

Lecture Notes in Computer Science

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Dedicated systems are fundamental for neuroscience experimental protocols that require timing determinism and synchronous stimuli generation. We developed a data acquisition and stimuli generator system for neuroscience research, optimized for recording timestamps from up to 6 spiking neurons and entirely specified in a high-level Hardware Description Language (HDL). Despite the logic complexity penalty of synthesizing from such a language, it was possible to implement our design in a low-cost small reconfigurable device. Under a modular framework, we explored two different memory arbitration schemes for our system, evaluating both their logic element usage and resilience to input activity bursts. One of them was designed with a decoupled and latency insensitive approach, allowing for easier code reuse, while the other adopted a centralized scheme, constructed specifically for our application. The usage of a high-level HDL allowed straightforward and stepwise code modifications to transform one architecture into the other. The achieved modularity is very useful for rapidly prototyping novel electronic instrumentation systems tailored to scientific research.

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A complex biological system: the fly's visual module

Cited by 5 publications

References 17 publications

Transmission of information in active networks

Transmission of information in active networks

In vivo performance of selective electron beam‐melted Ti‐6Al‐4V structures

Modular Acquisition and Stimulation System for Timestamp-Driven Neuroscience Experiments

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