Synaptic transmission is the key system for the information transfer and elaboration among neurons. Nevertheless, a synapse is not a standing alone structure but it is a part of a population of synapses inputting the information from several neurons on a specific area of the dendritic tree of a single neuron. This population consists of excitatory and inhibitory synapses the inputs of which drive the postsynaptic membrane potential in the depolarizing (excitatory synapses) or depolarizing (inhibitory synapses) direction modulating in such a way the postsynaptic membrane potential. The postsynaptic response of a single synapse depends on several biophysical factors the most important of which is the value of the membrane potential at which the response occurs. The concurrence in a specific time window of inputs by several synapses located in a specific area of the dendritic tree can, consequently, modulate the membrane potential such to severely influence the single postsynaptic response. The degree of modulation operated by the synaptic population depends on the number of synapses active, on the relative proportion between excitatory and inbibitory synapses belonging to the population and on their specific mean firing frequencies. In the present paper we show results obtained by the simulation of the activity of a single Glutamatergic excitatory synapse under the influence of two different populations composed of the same proportion of excitatory and inhibitory synapses but having two different sizes (total number of synapses). The most relevant conclusion of the present simulations is that the information transferred by the single synapse is not and independent simple transition between a pre- and a postsynaptic neuron but is the result of the cooperation of all the synapses which concurrently try to transfer the information to the postsynaptic neuron in a given time window. This cooperativeness is mainly operated by a simple mechanism of modulation of the postsynaptic membrane potential which influences the amplitude of the different components forming the postsynaptic excitatory response.

突触传递是神经元之间信息传递和加工的关键系统。然而，突触不是一个独立的结构，而是突触群体的一部分，从单个神经元树突树的特定区域上的几个神经元输入信息。该群体由兴奋性和抑制性突触组成，其输入驱动去极化（兴奋性突触）或去极化（抑制性突触）方向的突触后膜电位，从而调节突触后膜电位。单个突触的突触后反应取决于几个生物物理因素，其中最重要的是发生反应的膜电位值。因此，位于树突树特定区域的几个突触在特定时间窗口的输入同时发生可以调节膜电位，从而严重影响单个突触后反应。突触群体操作的调制程度取决于活跃的突触数量、属于群体的兴奋性和抑制性突触之间的相对比例以及它们特定的平均发射频率。在本文中，我们展示了在由相同比例的兴奋性和抑制性突触组成但具有两种不同大小（突触总数）的两个不同群体的影响下，通过模拟单个谷氨酸能兴奋性突触的活性获得的结果。本模拟最相关的结论是，单个突触传递的信息不是突触前和突触后神经元之间独立的简单转换，而是所有突触同时尝试将信息传递到给定时间窗口内的突触后神经元。这种协同性主要通过一种简单的突触后膜电位调制机制来操作，该机制影响形成突触后兴奋性反应的不同成分的幅度。