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Behavior and Nervous System Function
Published in Alan G. Heath, Water Pollution and Fish Physiology, 2018
It has frequently been observed that fish exposed to DDT exhibit hyperexcitability to mechanical stimuli, such as those produced by tapping on the side of an aquarium. This is sensed by the lateral line so Peters and Weber (1977) tested the threshold of the lateral line organs by providing them with a controlled mechanical stimulus and found they were not altered by DDT, even though Anderson (1968) had earlier reported that DDT caused the lateral line organs in trout to produce a more prolonged burst of activity following a single mechanical stimulus. Thus, the DDT effect on reflex responses to external stimuli (Anderson, 1970; Peters and Weber, 1977) must involve central nervous system changes, perhaps in part brought about by the abnormal input from the bursting activity seen at lower temperatures and more direct effects of DDT on neuronal function within the nervous system (Narahashi and Haas, 1968).
The Physics of Neural Activity: A Statistical Mechanics Perspective
Published in Perambur S. Neelakanta, Dolores F. De Groff, Neural Network Modeling, 2018
Perambur S. Neelakanta, Dolores F. De Groff
In the continuous/graded state transition corresponding to a moderate time-scale order, the firing pattern could be of two types: (1) The burst discharge pattern characterized by the output of an individual neuron being a series of separated bursts of activity rather than single spikes that is, the network fires a fixed pattern for some time and then suddenly changes to a different pattern which is also maintained for many time steps and (2) thequasi-reverberation pattern which corresponds to each neuron making a deterministic fire or no-fire decision at multiples of a basic unit of time; and a group of such neurons may form a closed, self-exciting loop yielding a cyclically repeating pattern called reverberation. Thompson and Gibson identified the possibility of the existence of both patterns as governed by the markovian statistics of neuronal state transition. Their further investigations on this topic [79]. with relevance to Little’s model, has revealed a single model neuron can produce a wide range of average output patterns including spontaneous bursting and tonic firing. Their study was also extended to two neuron activities. On the basis of their results, they conclude that Little’s model “produces a remarkably wide range of physically interesting average output patterns …. In Little’s model, the most probable behavior [of the neuronal network] is a simple consequence of the synaptic connectivity … That is, the type of each neuron and the synaptic connections are the primary properties. They determine the most likely behavior of the network. The actual output could be slightly modified or stabilized as a result of the various secondary effects” [such as accommodation or postinhibitory rebound, etc.].
Brain Dynamics: Neural Systems in Space and Time
Published in Ranjit Kumar Upadhyay, Satteluri R. K. Iyengar, Spatial Dynamics and Pattern Formation in Biological Populations, 2021
Ranjit Kumar Upadhyay, Satteluri R. K. Iyengar
with I2=0,αij=0for(i,j)≠(2,1); α21(x)=0ifx<(b−a)/10, and = 1 otherwise. For numerical simulation, the authors considered the case I(x)=130ifx<(b−a)/10,and=0,otherwise. Further, they have shown that neuron 1 is not affected by the coupling, but for neuron 2, they observed propagation of bursting oscillations from neuron 1 to neuron 2. As the coupling acts only on the right side of the neuron 2, oscillations propagate from right to left and a short propagation was observed toward the right boundary.
Emerging memristive neurons for neuromorphic computing and sensing
Published in Science and Technology of Advanced Materials, 2023
Zhiyuan Li, Wei Tang, Beining Zhang, Rui Yang, Xiangshui Miao
Innovatively, Kumar et al. reported a third-order nanocircuit element (third-order memristor) based on NbO2 Mott transition dynamics to perform many key neuronal spiking behaviors [102]. The proposed third-order memristive neuron, which consists of a NbO2-based Mott volatile memristive switch, an internal series resistor defined by an electrode interface), and an internal parallel capacitor defined by the metal contacts clamped in the dielectric (Figure 5(a)). Note that the device includes three state variables: temperature, charge on internal capacitor and speed of Mott transition, each of which corresponds to a dynamic physical process. In order to induce the desired higher-order Mott transition dynamics, the geometric structure and material stoichiometry of the neuron devices were carefully designed to emulate rich neuronal dynamics. The equivalent circuit model of the device is shown in Figure 5(b). When powered by a tunable constant bias voltage, different regions of its I-V curve are accessed by load lines determined by the internal resistor and the applied voltage (Figure 5(c)). Interestingly, the single neuron device could produce 15 different neuronal dynamics by tunning the voltage across the device, such as spiking, bursting, and chaos, etc., as shown in Figure 5(d). This novel work provided new insights into very compact and densely functional biologically plausible neuromorphic computing.
Adaptive Closed-Loop Deep Brain Stimulator Coding Techniques for Target Detections in Parkinson’s
Published in IETE Journal of Research, 2021
Venkateshwarla Rama Raju, Dabbeta Anji Reddy, D. Narsimha, Konda Srinivas, Balmuri Kavitha Rani
The local field potentials had given important scientific insights into Parkinson disease in particular with β-band-oscillations. This phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated primate interest branching from observations in a 1-methyl-4- -model [48]. With LFPs, the β-fluctuations associate positively with rigidity and also Bradykinesia. The consequential loss of dopaminergic neurons in the SNpc, the feature of trademark of PD, is differentiated by the onset of Parkinson’s motor-features like Bradykinesia and rigidity in these MPTP-treated monkeys [24,51,102]. Signal acquisitions from single-neuron single-unit-activity recordings from the subthalamus and also globus-pallidus in these monkeys have acknowledged an augmented stimulus-firing-rate accompanied with synchronous fluctuatory bursting-activity which was not found in normal-controls [21,53]. The augmented flucuatory-activity examined in MPTP-treated monkeys was consequently set up in the β-band frequency of local field potentials acquired from the subthalamic-nuclei of human Parkinson’s underwent-surgery.
Characterization of the solution concentration variation in microstructure by phase imaging
Published in Journal of Modern Optics, 2020
Ying Ji, Shuang Fu, Mingming Zhang, Xiang Li, Yawei Wang
In this paper, a microscopic method for monitoring solution concentration variation based on QPI is proposed. The sampling point is determined by calculating the modulus squared of the gradient associated with the sample phase. Then phase imaging experiments are implemented to verify that the concentration variation can be described by the phase shift. The neuronal dynamics model Chay is rewritten and the optical phase information is successfully applied to describe the bursting pattern of a neuron in simulation. All the above indicates that this method can observe the concentration variation in the microstructure dynamically and non-invasively with a relatively low cost and simple operation, hence it has a good application prospect in fields of industry and biology. Besides, it has some limitations, such as the sensitivity of this method is affected by the type of the solution and it is hard to quantitatively observe the concentration variation of the cytoplasm when the specimen structure is too complex. These are also the works could be carried out in our future research.