Persistent cortical activity: Mechanisms of generation and effects on neuronal excitability
Persistent cortical activity: Mechanisms of generation and effects on neuronal excitability
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DOI：
10.1093/cercor/bhg104
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发表时间：
2003-11-01
期刊：
影响因子：
3.7
通讯作者：
Bal, T
中科院分区：
文献类型：
--
作者：
McCormick, DA;Shu, YS;Bal, T
前额叶皮质和视觉皮质中的局部皮质网络能够自发地产生持续数秒或更长时间的活动。这种持续的活动是通过锥体细胞之间的反复兴奋产生的，这种兴奋受到反馈抑制的控制，可以有快速的起效和快速的抵消。活动周期与神经元对细胞内注入电流脉冲的反应性显著增加有关，特别是那些较小幅度的脉冲。独立模拟去极化、膜电导增加和与持续活动相关的噪声增加表明，去极化是神经元反应性增加的主要原因，尽管膜噪声的增加也促进了对小输入的反应。这些结果表明，与工作记忆任务绩效相关的持续活动可能主要是通过递归网络产生的。他们还表明，反馈途径，如那些涉及选择性注意的途径，可能会通过突触轰击对神经元的反应性产生强大的影响。
Local cortical networks in the prefrontal cortex and visual cortex are capable of spontaneously generating sustained activity for periods of seconds or longer. This sustained activity is generated through recurrent excitation between pyramidal cells that is controlled by feedback inhibition and can have both a rapid onset and a rapid offset. The period of activity is associated with a marked increase in neuronal responsiveness to the intracellular injection of current pulses, especially those of smaller amplitude. Independently mimicking the depolarization, increase in membrane conductance and increase in noise associated with sustained activity revealed that the depolarization is largely responsible for the increase in neuronal responsiveness, although an increase in membrane noise also facilitates responses to small inputs. These results indicate that the persistent activity associated with the performance of working memory tasks may be generated largely through recurrent networks. They also suggest that feedback pathways, such as those involved in selective attention, may exert a powerful influence on neuronal responsiveness through synaptic bombardment.