Dynamics and coherence resonance in a thermosensitive neuron driven by photocurrent

A feasible neuron model can be effective to estimate the mode transition in neural activities in a complex electromagnetic environment.When neurons are exposed to electromagnetic field,the continuous magnetization and polarization can generate nonlinear effect on the exchange and propagation of ions in the cell,and then the firing patterns can be regulated completely.The conductivity of ion channels can be affected by the temperature and the channel current is adjusted for regulating the excitability of neurons.In this paper,a phototube and a thermistor are used to the functions of neural circuit.The phototube is used to capture external illumination for energy injection,and a continuous signal source is obtained.The thermistor is used to percept the changes of temperature,and the channel current is changed to adjust the excitability of neuron.This functional neural circuit can encode the external heat(temperature)and illumination excitation,and the dynamics of neural activities is investigated in detail.The photocurrent generated in the phototube can be used as a signal source for the neural circuit,and the thermistor is used to estimate the conduction dependence on the temperature for neurons under heat effect.Bifurcation analysis and Hamilton energy are calculated to explore the mode selection.It is found that complete dynamical properties of biological neurons can be reproduced in spiking,bursting,and chaotic firing when the phototube is activated as voltage source.The functional neural circuit mainly presents spiking states when the photocurrent is handled as a stable current source.Gaussian white noise is imposed to detect the occurrence of coherence resonance.This neural circuit can provide possible guidance for investigating dynamics of neural networks and potential application in designing sensitive sensors.

Control of firing activities in thermosensitive neuron by activating excitatory autapse

Temperature has distinct influence on the activation of ion channels and the excitability of neurons,and careful change in temperature can induce possible mode transition in the neural activities.The formation and development of autapse connection to neuron can enhance its self-adaption to external stimulus,and thus the firing patterns in neuron can be controlled effectively.The autapse is activated to drive a thermosensitive neuron,which is developed from the FitzHugh-Nagumo neural circuit by incorporating a thermistor,and the dynamics in the neural activities is explored to find mode dependence on the temperature and autaptic current.It is found that the firing modes can be controlled by temperature,and the neuron is wakened from resting state to periodic oscillation with the increase of temperature.Furthermore,the intensity and the intrinsic time delay in the autapse are respectively adjusted to control the neural activities,and it is confirmed that appropriate setting for autaptic current can balance and enhance the temperature effect on the neural activities.

Effect of astrocyte on synchronization of thermosensitive neuron–astrocyte minimum system

Astrocytes have a regulatory function on the central nervous system(CNS), especially in the temperature-sensitive hippocampal region. In order to explore the thermosensitive dynamic mechanism of astrocytes in the CNS, we establish a neuron-astrocyte minimum system to analyze the synchronization change characteristics based on the Hodgkin-Huxley model, in which a pyramidal cell and an interneuron are connected by an astrocyte. The temperature range is set as 0-40 ℃ to juggle between theoretical calculation and the reality of a brain environment. It is shown that the synchronization of thermosensitive neurons exhibits nonlinear behavior with changes in astrocyte parameters. At a temperature range of0 ℃-18 ℃, the effects of the astrocyte can provide a tremendous influence on neurons in synchronization. We find the existence of a value for inositol triphosphate(IP_(3)) production rate and feedback intensities of astrocytes to neurons, which can ensure the weak synchronization of two neurons. In addition, it is revealed that the regulation of astrocytes to pyramidal cells is more sensitive than that to interneurons. Finally, it is shown that the synchronization and phase transition of neurons depend on the change in Ca^(2+) concentration at the temperature of weak synchronization. The results in this paper provide some enlightenment on the mechanism of cognitive dysfunction and neurological disorders with astrocytes.