Neurons synaptically interacting in a conductive medium generate extracellular endogenous electric fields (EFs) that reciprocally affect membrane potential. Exogenous EFs modulate neuronal activity, and their clinical applications are being profusely explored. However, whether endogenous EFs contribute to network synchronization remains unclear. We analyzed spontaneously generated slow-wave activity in the cerebral cortex network in vitro, which allowed us to distinguish synaptic from nonsynaptic mechanisms of activity propagation and synchronization. Slow oscillations generated EFs that propagated independently of synaptic transmission. We demonstrate that cortical oscillations modulate spontaneous rhythmic activity of neighboring synaptically disconnected cortical columns if layers are aligned. We provide experimental evidence that these EF-mediated effects are compatible with electric dipoles. With a model of interacting dipoles, we reproduce the experimental measurements and predict that endogenous EF–mediated synchronizing effects should be relevant in the brain. Thus, experiments and models suggest that electric-dipole interactions contribute to synchronization of neighboring cortical columns.

在导电介质中突触相互作用的神经元产生相互影响膜电位的细胞外内源性电场 (EF)。外源性 EFs 调节神经元活动，并且正在大量探索它们的临床应用。然而，内源性 EFs 是否有助于网络同步仍不清楚。我们在体外分析了大脑皮层网络中自发产生的慢波活动，这使我们能够区分突触和非突触的活动传播和同步机制。缓慢的振荡产生独立于突触传递传播的 EF。我们证明，如果层对齐，皮质振荡会调节相邻突触断开的皮质柱的自发节律活动。我们提供实验证据表明这些 EF 介导的效应与电偶极子兼容。使用相互作用偶极子模型，我们重现了实验测量结果，并预测内源性 EF 介导的同步效应应该与大脑相关。因此，实验和模型表明，电偶极子相互作用有助于相邻皮质柱的同步。