Nomura Masaki, Fukai Tomoki, Aoyagi Toshio
Department of Applied Analysis and Complex Dynamical Systems, Graduate School of Informatics, Kyoto University, Kyoto 606-8501, Japan.
Neural Comput. 2003 Sep;15(9):2179-98. doi: 10.1162/089976603322297340.
Fast-spiking (FS) interneurons have specific types (Kv3.1/3.2 type) of the delayed potassium channel, which differ from the conventional Hodgkin-Huxley (HH) type potassium channel (Kv1.3 type) in several aspects. In this study, we show dramatic effects of the Kv3.1/3.2 potassium channel on the synchronization of the FS interneurons. We show analytically that two identical electrically coupled FS interneurons modeled with Kv3.1/3.2 channel fire synchronously at arbitrary firing frequencies, unlike similarly coupled FS neurons modeled with Kv1.3 channel that show frequency-dependent synchronous and antisynchronous firing states. Introducing GABA(A) receptor-mediated synaptic connections into an FS neuron pair tends to induce an antisynchronous firing state, even if the chemical synapses are bidirectional. Accordingly, an FS neuron pair connected simultaneously by electrical and chemical synapses achieves both synchronous firing state and antisynchronous firing state in a physiologically plausible range of the conductance ratio between electrical and chemical synapses. Moreover, we find that a large-scale network of FS interneurons connected by gap junctions and bidirectional GABAergic synapses shows similar bistability in the range of gamma frequencies (30-70 Hz).
快速放电（FS）中间神经元具有特定类型（Kv3.1/3.2型）的延迟钾通道，它在几个方面与传统的霍奇金-赫胥黎（HH）型钾通道（Kv1.3型）不同。在本研究中，我们展示了Kv3.1/3.2钾通道对FS中间神经元同步性的显著影响。我们通过分析表明，用Kv3.1/3.2通道建模的两个相同的电耦合FS中间神经元在任意放电频率下都能同步放电，这与用Kv1.3通道建模的类似耦合FS神经元不同，后者表现出频率依赖性的同步和反同步放电状态。将GABA(A)受体介导的突触连接引入FS神经元对中，即使化学突触是双向的，也倾向于诱导反同步放电状态。因此，通过电突触和化学突触同时连接的FS神经元对在电突触和化学突触电导比的生理合理范围内实现了同步放电状态和反同步放电状态。此外，我们发现，由缝隙连接和双向GABA能突触连接的大规模FS中间神经元网络在γ频率范围（30-70Hz）内表现出类似的双稳性。
