The interaction between spontaneous and externally evoked neuronal activity is fundamental for a functional brain. Increasing evidence suggests that bursts of high-power oscillations in the 15- to 30-Hz beta-band represent activation of internally generated events and mask perception of external cues. Yet demonstration of the effect of beta-power modulation on perception in real time is missing, and little is known about the underlying mechanism. Here, we used a closed-loop stimulus-intensity adjustment system based on online burst-occupancy analyses in rats involved in a forepaw vibrotactile detection task. We found that the masking influence of burst occupancy on perception can be counterbalanced in real time by adjusting the vibration amplitude. Offline analysis of firing rates (FRs) and local field potentials across cortical layers and frequency bands confirmed that beta-power in the somatosensory cortex anticorrelated with sensory evoked responses. Mechanistically, bursts in all bands were accompanied by transient synchronization of cell assemblies, but only beta-bursts were followed by a reduction of FR. Our closed loop approach reveals that spontaneous beta-bursts reflect a dynamic state that competes with external stimuli.

自发和外部诱发的神经元活动之间的相互作用是功能性大脑的基础。越来越多的证据表明，15 到 30 Hz β 波段中的高功率振荡爆发代表内部生成事件的激活和外部线索的屏蔽感知。然而，缺乏对β-功率调制对实时感知的影响的演示，并且对潜在机制知之甚少。在这里，我们在参与前爪振动触觉检测任务的大鼠中使用了基于在线突发占用分析的闭环刺激强度调整系统。我们发现突发占用对感知的掩蔽影响可以通过调整振幅实时抵消。对皮质层和频带的放电率 (FR) 和局部场电位的离线分析证实，体感皮层中的 β 功率与感觉诱发反应抗相关。从机制上讲，所有波段的爆发都伴随着细胞组件的瞬态同步，但只有 β 爆发之后是 FR 的减少。我们的闭环方法表明，自发的 β 爆发反映了与外部刺激竞争的动态状态。