人脑由数十亿神经元构成，长久以来人们以为只要读懂神经元之间的放电与连结，就能解释知觉、情绪、思考、行为与相关疾病。但多个实验室在 2025 年于《Science》发表的一组研究指出，仅盯著神经元远远不够：星形胶质细胞（astrocytes）不只是「支援细胞」，更像是监督者，能调校脑回路并改变整体脑状态或心境。

星形胶质细胞在许多脑区的数量甚至多于神经元，形态复杂，突起可包覆大量突触，位置上非常适合影响讯息流。它们不像神经元那样以毫秒尺度快速传讯，而是监测并调节更高层级的网路活动，透过所谓的神经调质（neuromodulation）把整体活动「旋钮式」地调高或调低，让大脑既不至于沉寂也不至于失控癫痫。研究者因此认为，过去只用神经元画出的调质模型，漏掉了关键的一层。

文章回顾了从 1989 年钙成像下观察到星形胶质细胞的钙波，到近年在果蝇、斑马鱼与小鼠中更清楚的分子链条：如去甲肾上腺素等调质物可启动星形胶质细胞，进而释放 ATP 并转为腺苷等讯号，抑制或重塑神经元活动，甚至驱动行为状态切换，例如斑马鱼在徒劳奋游约二十秒后「放弃」。作者也指出，睡眠与精神疾患等涉及整体状态失衡的问题，可能需要把星形胶质细胞纳入核心机制与药物靶点来重新思考。

For over a century, neuroscience largely treated neuronal firing and connectivity as the main code behind perception, emotion, thought, behavior, and disease. A trio of papers published in Science in 2025 argues that this neuron-centric view is incomplete, presenting strong evidence that astrocytes—once framed as mere support cells—act more like supervisors that tune circuits and influence global brain states such as arousal, anxiety, or apathy.

Astrocytes can outnumber neurons in many regions and physically interface with vast numbers of synapses, placing them in an ideal position to shape information flow. Unlike the millisecond-speed signaling of neurons, astrocytes operate on slower timescales, monitoring network activity and implementing neuromodulation—dialing overall activity up or down to keep circuits functional and to enable rapid transitions between brain states without requiring changes in neuronal wiring.

The article traces key experiments from early calcium-imaging discoveries to recent mechanistic work across fruit flies, zebrafish, and mice. In these studies, neuromodulators such as norepinephrine trigger astrocyte calcium dynamics that lead to releases of molecules like ATP and downstream adenosine signaling, which then alters neuronal activity and behavior—such as prompting a zebrafish to stop a futile effort. The emerging picture suggests astrocytes are a missing layer in many models and may be central to understanding sleep regulation and neuropsychiatric disorders.