Are biological neurons that vicious ? Or only their models ?

Josephson junction simulation of neurons

With the goal of understanding the intricate behavior and dynamics of collections of neurons, we present superconducting circuits containing Josephson junctions that model biologically realistic neurons. These "Josephson junction neurons" reproduce many characteristic behaviors of biological neurons such as action potentials, refractory periods, and firing thresholds. They can be coupled together in ways that mimic electrical and chemical synapses. Using existing fabrication technologies, large interconnected networks of Josephson junction neurons would operate fully in parallel. They would be…

Statistical data assimilation for estimating electrophysiology simultaneously with connectivity within a biological neuronal network

A method of data assimilation (DA) is employed to estimate electrophysiological parameters of neurons simultaneously with their synaptic connectivity in a small model biological network. The DA procedure is cast as an optimization, with a cost function consisting of both a measurement error and a model error term. An iterative reweighting of these terms permits a systematic method to identify the lowest minimum, within a local region of state space, on the surface of a non-convex cost function. In the model, two sets of parameter values are associated with two particular functional modes of ne…

Biological Principles in Self-Organization of Young Brain - Viewed from Kohonen Model

Variants of the Kohonen model are proposed to study biological principles of self-organization in a model of young brain. We suggest a function to measure aquired knowledge and use it to auto-adapt the topology of neuronal connectivity, yielding substantial organizational improvement relative to the standard model. In the early phase of organization with most intense learning, we observe that neural connectivity is of Small World type, which is very efficient to organize neurons in response to stimuli. In analogy to human brain where pruning of neural connectivity (and neuron cell death) occur…

An excitable electronic circuit as a sensory neuron model

An electronic circuit device, inspired on the FitzHugh-Nagumo model of neuronal excitability, was constructed and shown to operate with characteristics compatible with those of biological sensory neurons. The nonlinear dynamical model of the electronics quantitatively reproduces the experimental observations on the circuit, including the Hopf bifurcation at the onset of tonic spiking. Moreover, we have implemented an analog noise generator as a source to study the variability of the spike trains. When the circuit is in the excitable regime, coherence resonance is observed. At sufficiently low …

简单统计物理模型在真实神经元网络中的成功与失败

Successes and failures of simple statistical physics models for a network of real neurons

研究利用小鼠大脑1000多个神经元的同步活动测量，检验统计物理模型，发现小区域密集采样时理论与实验高度定量吻合，而大区域稀疏采样导致模型失效。

场闭合、冰神经元，以及树突何时成为基元

Field closure, ice neurons, and when a dendrite is a motif

本研究提出冰神经元作为零增益界面模型，揭示生物神经元中几何、动力学与场相互塑造，场闭合增强远端持久性，区别于纯结构形态。