Arousal results in widespread activation of brain areas to increase their response in task and behavior relevant ways. Mediated by the Ascending Reticular Arousal System (ARAS), arousal-dependent inputs interact with neural circuitry to shape their dynamics. In the occipital cortex, such inputs may trigger shifts between dominant oscillations, where \(\alpha\) activity is replaced by \(\gamma\) activity, or vice versa. A salient example of this are spectral power alternations observed while eyes are opened and/or closed. These transitions closely follow fluctuations in arousal, suggesting a common origin. To better understand the mechanisms at play, we developed and analyzed a computational model composed of two modules: a thalamocortical feedback circuit coupled with a superficial cortical network. Upon activation by noise-like inputs originating from the ARAS, our model is able to demonstrate that noise-driven non-linear interactions mediate transitions in dominant peak frequency, resulting in the simultaneous suppression of \(\alpha\) limit cycle activity and the emergence of \(\gamma\) oscillations through coherence resonance. Reduction in input provoked the reverse effect - leading to anticorrelated transitions between \(\alpha\) and \(\gamma\) power. Taken together, these results shed a new light on how arousal shapes oscillatory brain activity.

唤醒导致大脑区域的广泛激活，以增加他们对任务和行为相关方式的反应。由上升网状唤醒系统 (ARAS) 介导，唤醒依赖输入与神经电路相互作用以形成其动态。在枕叶皮层，这样的输入可能会触发主导振荡之间的转换，其中\(\alpha\)活动被\(\gamma\)取代活动，反之亦然。一个突出的例子是在眼睛睁开和/或闭合时观察到的光谱功率变化。这些转变紧随唤醒的波动，表明一个共同的起源。为了更好地理解起作用的机制，我们开发并分析了一个由两个模块组成的计算模型：一个丘脑皮层反馈电路和一个浅表皮层网络。在由源自 ARAS 的类噪声输入激活后，我们的模型能够证明噪声驱动的非线性相互作用介导了主峰频率的跃迁，从而同时抑制了\(\alpha\)极限循环活动和\(\gamma\)的出现通过相干共振振荡。输入的减少引发了相反的效果——导致\(\alpha\)和\(\gamma\)功率之间的反相关转换。总而言之，这些结果为唤醒如何塑造大脑振荡活动提供了新的线索。