Perineuronal nets (PNNs) are specialized structures of the extracellular matrix that surround the soma and proximal dendrites of certain neurons in the central nervous system, particularly parvalbumin-expressing interneurons. Their appearance overlaps the maturation of neuronal circuits and the closure of critical periods in different regions of the brain, setting their connectivity and abruptly reducing their plasticity. As a consequence, the digestion of PNNs, as well as the removal or manipulation of their components, leads to a boost in this plasticity and can play a key role in the functional recovery from different insults and in the etiopathology of certain neurologic and psychiatric disorders. Here we review the structure, composition, and distribution of PNNs and their variation throughout the evolutive scale. We also discuss methodological approaches to study these structures. The function of PNNs during neurodevelopment and adulthood is discussed, as well as the influence of intrinsic and extrinsic factors on these specialized regions of the extracellular matrix. Finally, we review current data on alterations in PNNs described in diseases of the central nervous system (CNS), focusing on psychiatric disorders. Together, all the data available point to the PNNs as a promising target to understand the physiology and pathologic conditions of the CNS.

神经周围网（PNN）是细胞外基质的特殊结构，围绕中枢神经系统中某些神经元的胞体和近端树突，特别是表达小白蛋白的中间神经元。它们的出现与神经元回路的成熟和大脑不同区域关键时期的关闭重叠，设定了它们的连通性并突然降低了它们的可塑性。因此，PNN 的消化以及其成分的去除或操纵会增强这种可塑性，并在不同损伤的功能恢复以及某些神经系统和精神疾病的病因病理学中发挥关键作用。在这里，我们回顾了 PNN 的结构、组成和分布及其在整个进化尺度上的变化。我们还讨论了研究这些结构的方法。讨论了神经发育和成年期间 PNN 的功能，以及内在和外在因素对细胞外基质这些特殊区域的影响。最后，我们回顾了中枢神经系统 (CNS) 疾病中描述的 PNN 改变的最新数据，重点关注精神疾病。总之，所有可用数据都表明 PNN 是了解中枢神经系统生理和病理状况的有希望的目标。