Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Proc Natl Acad Sci U S A. 2012 Oct 9;109(41):E2832-41. doi: 10.1073/pnas.1206557109. Epub 2012 Sep 24.
Although cholinergic innervation of the cortex by the nucleus basalis (NB) is known to modulate cortical neuronal responses and instruct cortical plasticity, little is known about the underlying cellular mechanisms. Using cell-attached recordings in vivo, we demonstrate that electrical stimulation of the NB, paired with visual stimulation, can induce significant potentiation of visual responses in excitatory neurons of the primary visual cortex in mice. We further show with in vivo two-photon calcium imaging, ex vivo calcium imaging, and whole-cell recordings that this pairing-induced potentiation is mediated by direct cholinergic activation of primary visual cortex astrocytes via muscarinic AChRs. The potentiation is absent in conditional inositol 1,4,5 trisphosphate receptor type 2 KO mice, which lack astrocyte calcium activation, and is stimulus-specific, because pairing NB stimulation with a specific visual orientation reveals a highly selective potentiation of responses to the paired orientation compared with unpaired orientations. Collectively, these findings reveal a unique and surprising role for astrocytes in NB-induced stimulus-specific plasticity in the cerebral cortex.
虽然基底神经节(NB)的胆碱能神经支配皮层已知可以调节皮层神经元的反应并指导皮层可塑性,但关于其潜在的细胞机制知之甚少。本研究采用在体细胞贴附记录,证明了 NB 的电刺激与视觉刺激相结合,可以在小鼠初级视觉皮层的兴奋性神经元中诱导显著的视觉反应增强。我们进一步通过在体双光子钙成像、离体钙成像和全细胞膜片钳记录表明,这种联合诱导的增强是通过烟碱型乙酰胆碱受体(mAChRs)介导的对初级视觉皮层星形胶质细胞的直接胆碱能激活。在缺失星形胶质细胞钙激活的条件性肌醇 1,4,5-三磷酸受体 2 敲除(KO)小鼠中,这种增强作用缺失,并且具有刺激特异性,因为将 NB 刺激与特定的视觉方向配对会导致对配对方向的反应产生高度选择性的增强,而对未配对方向的反应则没有。总之,这些发现揭示了星形胶质细胞在 NB 诱导的大脑皮层中刺激特异性可塑性中的独特而令人惊讶的作用。