1] Florey Institute, University of Melbourne, Melbourne, Victoria, Australia. [2] Physiologisches Institut, Universität Bern, Bern, Switzerland. [3] NeuroCure Cluster of Excellence, Humboldt University, Berlin, Germany.
Bioengineering Department, California Institute of Technology, Pasadena, California, USA.
Nat Neurosci. 2014 Mar;17(3):383-90. doi: 10.1038/nn.3646. Epub 2014 Feb 2.
Recent evidence in vitro suggests that the tuft dendrites of pyramidal neurons are capable of evoking local NMDA receptor-dependent electrogenesis, so-called NMDA spikes. However, it has so far proved difficult to demonstrate their existence in vivo. Moreover, it is not clear whether NMDA spikes are relevant to the output of pyramidal neurons. We found that local NMDA spikes occurred in tuft dendrites of layer 2/3 pyramidal neurons both spontaneously and following sensory input, and had a large influence on the number of output action potentials. Using two-photon activation of an intracellular caged NMDA receptor antagonist (tc-MK801), we found that isolated NMDA spikes typically occurred in multiple branches simultaneously and that sensory stimulation substantially increased their probability. Our results demonstrate that NMDA receptors have a vital role in coupling the tuft region of the layer 2/3 pyramidal neuron to the cell body, enhancing the effectiveness of layer 1 input.
最近的体外证据表明，锥体细胞的树突簇能够引发局部 NMDA 受体依赖性电生成，即所谓的 NMDA 棘波。然而，迄今为止，要证明其在体内的存在一直很困难。此外，尚不清楚 NMDA 棘波是否与锥体细胞的输出有关。我们发现，局部 NMDA 棘波在 2/3 层锥体细胞的树突簇中自发发生，并在感觉输入后发生，对输出动作电位的数量有很大影响。使用细胞内笼 NMDA 受体拮抗剂（tc-MK801）的双光子激活，我们发现，孤立的 NMDA 棘波通常同时发生在多个分支中，而感觉刺激大大增加了它们的可能性。我们的结果表明，NMDA 受体在将 2/3 层锥体细胞的树突簇与细胞体相耦合方面起着至关重要的作用，增强了 1 层输入的有效性。
