Stimulus repetition modulates gamma-band synchronization in primate visual cortex
Stimulus repetition modulates gamma-band synchronization in primate visual cortex
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DOI：
10.1073/pnas.1309714111
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发表时间：
2014-03-04
影响因子：
11.1
通讯作者：
Fries, Pascal
中科院分区：
文献类型：
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作者：
Brunet, Nicolas M.;Bosman, Conrado A.;Fries, Pascal
当感觉刺激重复时，神经元放电率和功能性MRI血氧水平依赖性反应通常会下降，而感知和行为表现要么保持不变，要么有所改善。神经元活动的另一个方面是神经元同步，它可以增强神经元对突触后目标的影响，而不依赖于神经元的放电速率。我们发现刺激重复导致神经元γ波段（类似于40- 90hz）同步的深刻变化。两只醒着的猕猴的皮质电图记录表明，视觉光栅刺激的重复呈现导致视觉诱导的V1区伽马带活动的稳定增加，V1区和V4区之间的伽马带同步，以及V4区伽马带活动。在相同的刺激条件下，另外两只猴子的V4区域的微电极记录可以直接比较多单元活动（MUA）的放电速率和伽马带同步强度，以及分离的单个单元，分为假定的锥体细胞和假定的中间神经元。MUA和假定的中间神经元显示重复相关的放电率下降，但伽马波段同步增加。假设的锥体细胞没有表现出与重复相关的放电速率变化，但弱刺激驱动单元的伽马带同步减少，强刺激驱动单元的伽马带同步保持不变。我们认为，重复相关的伽马波段同步变化维持了区域间刺激信号，并通过伽马同步锥体细胞尖峰增强了刺激表征。
When a sensory stimulus repeats, neuronal firing rate and functional MRI blood oxygen level-dependent responses typically decline, yet perception and behavioral performance either stay constant or improve. An additional aspect of neuronal activity is neuronal synchronization, which can enhance the impact of neurons onto their postsynaptic targets independent of neuronal firing rates. We show that stimulus repetition leads to profound changes of neuronal gamma-band (similar to 40-90 Hz) synchronization. Electrocorticographic recordings in two awake macaque monkeys demonstrated that repeated presentations of a visual grating stimulus resulted in a steady increase of visually induced gamma-band activity in area V1, gamma-band synchronization between areas V1 and V4, and gamma-band activity in area V4. Microelectrode recordings in area V4 of two additional monkeys under the same stimulation conditions allowed a direct comparison of firing rates and gamma-band synchronization strengths for multiunit activity (MUA), as well as for isolated single units, sorted into putative pyramidal cells and putative interneurons. MUA and putative interneurons showed repetition-related decreases in firing rate, yet increases in gamma-band synchronization. Putative pyramidal cells showed no repetition-related firing rate change, but a decrease in gamma-band synchronization for weakly stimulus-driven units and constant gamma-band synchronization for strongly driven units. We propose that the repetition-related changes in gamma-band synchronization maintain the interareal stimulus signaling and sharpen the stimulus representation by gamma-synchronized pyramidal cell spikes.