Joo Pangyu, Lee Heonsoo, Wang Shiyong, Kim Seunghwan, Hudetz Anthony G
Center for Consciousness Science, Department of Anesthesiology, University of Michigan, Ann Arbor, MI, United States.
Department of Physics, Pohang University of Science and Technology, Pohang, South Korea.
Front Comput Neurosci. 2021 Oct 7;15:738362. doi: 10.3389/fncom.2021.738362. eCollection 2021.
In a cerebral hypometabolic state, cortical neurons exhibit slow synchronous oscillatory activity with sparse firing. How such a synchronization spatially organizes as the cerebral metabolic rate decreases have not been systemically investigated. We developed a network model of leaky integrate-and-fire neurons with an additional dependency on ATP dynamics. Neurons were scattered in a 2D space, and their population activity patterns at varying ATP levels were simulated. The model predicted a decrease in firing activity as the ATP production rate was lowered. Under hypometabolic conditions, an oscillatory firing pattern, that is, an ON-OFF cycle arose through a failure of sustainable firing due to reduced excitatory positive feedback and rebound firing after the slow recovery of ATP concentration. The firing rate oscillation of distant neurons developed at first asynchronously that changed into burst suppression and global synchronization as ATP production further decreased. These changes resembled the experimental data obtained from anesthetized rats, as an example of a metabolically suppressed brain. Together, this study substantiates a novel biophysical mechanism of neuronal network synchronization under limited energy supply conditions.
在大脑低代谢状态下，皮质神经元表现出缓慢的同步振荡活动且放电稀疏。随着大脑代谢率降低，这种同步性如何在空间上组织起来尚未得到系统研究。我们开发了一种漏电整合-发放神经元的网络模型，该模型额外依赖于ATP动力学。神经元散布在二维空间中，并模拟了它们在不同ATP水平下的群体活动模式。该模型预测，随着ATP产生率降低，放电活动会减少。在低代谢条件下，由于兴奋性正反馈减少以及ATP浓度缓慢恢复后的反弹放电，可持续放电失败，从而出现了振荡放电模式，即开-关循环。随着ATP产生进一步减少，远处神经元的放电率振荡起初异步发展，随后转变为爆发抑制和全局同步。这些变化类似于从麻醉大鼠获得的实验数据，麻醉大鼠是代谢受抑制大脑的一个例子。总之，本研究证实了在能量供应有限条件下神经元网络同步的一种新的生物物理机制。
