生理心理学（二）——读《心理学改变思维》（二十六）

上一节中提到的髓鞘（myelin sheath），实际是胶质细胞（glial cell）的产物。什么是胶质细胞呢？

cell in the nervous system that plays a role in the formation of myelin and the blood–brain barrier, responds to injury, removes debris, and enhances learning and memory

髓鞘在上一节已经提到，其作用是包裹在轴突以外，从而隔离神经元信号（绝缘体，insulator）：

glial cells wrapped around axons that act as insulators of the neuron’s signal

其来自于少突胶质细胞（oligodendrocyte）：

promotes new connections among nerve cells and releases chemicals to aid in healing.

可以帮助神经细胞产生新的连接以及释放修复用的化学物质。

另一种胶质细胞是星状胶质细胞（astrocytes），比髓鞘数量更多：

The most abundant of glial cells are astrocytes. Astrocytes are shaped like stars, hence their name (think of the words astronomy or astrology). A single astrocyte interacts with as many as 300,000 to 1,000,000 neurons. Astrocytes communicate closely with neurons, increase the accuracy of their transmission, help to control blood flow in the brain, and play a vital role in the development of the embryo (Metea & Newman, 2006). Astrocytes, in concert with other glial cells, are intimately involved in thought, memory, and the immune system (Gibbs & Bowser, 2009; Koob, 2009).

每个星状胶质细胞连接30万到100万个神经元，其作用是：

- 提高信息交流的准确性

- 帮助控制大脑中的血液流动

- 在胚胎（embryo）的发育过程中起到关键作用

- 而且和其他胶质细胞配合，与我们的思维、记忆以及免疫系统都有很强的关系

当出现血脑屏障（blood–brain barrier）：

a protective shield that insulates the brain from infection by bacteria, many poisons, and other nasty intruders.

时候，都有星状胶质细胞的积极参与。

胶质细胞还负责清理大脑细胞的垃圾，未来可能会对抑郁症、精神分裂、阿尔兹海默症等的治疗起作用。