Simulations of neural activity are commonly based on differential equations. We address the question what can be achieved with a simplified discrete model. The proposed model resembles artificial neural networks enriched with additional biologically inspired features. A neuron has several states, and the state transitions follow endogenous patterns which roughly correspond to firing behavior observed in biological neurons: oscillatory, tonic, plateauing, etc. Neural interactions consist of two components: synaptic connections and extrasynaptic emission of neurotransmitters. The dynamics is asynchronous and event-based; the events correspond to the changes in neurons activity. This model is innovative in introducing discrete framework for modeling neurotransmitter interactions which play the important role in neuromodulation. We simulate rhythmic activity of small neural ensembles like central pattern generators (CPG). The modeled examples include: the biphasic rhythm generated by the half-center mechanism with the post-inhibitory rebound (like the leech heartbeat CPG), the triphasic rhythm (like in pond snail feeding CPG) and the pattern switch in the system of several neurons (like the switch between ingestion and egestion in Aplysia feeding CPG). The asynchronous dynamics allows to obtain multi-phasic rhythms with phase durations close to their biological prototypes. The perspectives of discrete modeling in biological research are discussed in the conclusion.

神经活动的模拟通常基于微分方程。我们解决了这个问题，用简化的离散模型可以实现什么。提出的模型类似于人工神经网络，具有丰富的生物学启发特征。神经元具有几种状态，并且状态转换遵循大致对应于生物神经元中观察到的放电行为的内源性模式：振荡，滋补，平稳等。神经相互作用包括两个部分：神经递质的突触连接和突触外发射。动态是异步的，基于事件；这些事件对应于神经元活动的变化。该模型在引入离散模型以建模神经递质相互作用方面具有创新性，该模型在神经调节中起重要作用。我们模拟像中央模式生成器（CPG）的小型神经乐团的节奏活动。建模的例子包括：由半中心机制产生的双相节律，具有抑制后的反弹（如水heart心跳CPG），三相节律（如池塘蜗牛饲喂CPG）和多个神经元系统中的模式转换（例如在海藻饲喂CPG中摄入和摄取之间的切换）。异步动力学允许获得相位持续时间接近其生物学原型的多相节律。结论中讨论了离散建模在生物学研究中的观点。由半中心机制产生的两相节律，具有抑制后的反弹（如水ech心跳CPG），三相节律（如池塘蜗牛喂养CPG）和多个神经元系统中的模式转换（如饲喂CPG的海葵的摄食和摄食）。异步动力学允许获得相位持续时间接近其生物学原型的多相节律。结论中讨论了离散建模在生物学研究中的观点。由半中心机制产生的两相节律，具有抑制后的反弹（如水ech心跳CPG），三相节律（如池塘蜗牛饲喂CPG）和多个神经元系统中的模式转换（如饲喂CPG的海葵的摄食和摄食）。异步动力学允许获得相位持续时间接近其生物学原型的多相节律。结论中讨论了离散建模在生物学研究中的观点。