Properties of Layer 6 Pyramidal Neuron Apical Dendrites
Properties of Layer 6 Pyramidal Neuron Apical Dendrites
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DOI：
10.1523/jneurosci.2254-10.2010
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发表时间：
2010-09-29
影响因子：
5.3
通讯作者：
Larkum, Matthew Evan
中科院分区：
文献类型：
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作者：
Ledergerber, Debora;Larkum, Matthew Evan
第6层（L 6）锥体神经元是唯一的新皮质锥体细胞类型，其顶树突终止于第4层而不是第1层。像第5层锥体神经元一样，它们参与丘脑的反馈回路，并投射到其他皮质区域。尽管它们在皮层微回路中的独特位置，但L 6神经元树突中的突触整合从未被研究过。鉴于所有其他新皮质锥体神经元都通过局部树突锋电位的产生来执行突触输入的主动整合，我们有兴趣建立L 6锥体神经元的顶端树突特性。我们测量了主动和被动特性的L 6锥体神经元的顶树突在大鼠皮层切片的躯体感觉区，使用双膜片钳记录从胞体和树突和钙成像。我们发现L 6锥体神经元与其他新皮层锥体神经元具有许多基本的树突特性，包括树突抑制控制下局部树突棘波的产生、电压依赖性支持反向传播动作电位、时间依赖性树突整合、远端I-h通道、频率依赖性Ca 2+棘波激活和远端顶树突NMDA棘波电发生。结果表明，L 6锥体神经元在第4层整合突触输入的方式类似于其他新皮层锥体神经元将输入整合到第1层。因此，L 6锥体神经元可以对到达颗粒层和亚颗粒层的输入执行类似的关联任务。
Layer 6 (L6) pyramidal neurons are the only neocortical pyramidal cell type whose apical dendrite terminates in layer 4 rather than layer 1. Like layer 5 pyramidal neurons, they participate in a feedback loop with the thalamus and project to other cortical areas. Despite their unique location in the cortical microcircuit, synaptic integration in dendrites of L6 neurons has never been investigated. Given that all other neocortical pyramidal neurons perform active integration of synaptic inputs via local dendritic spike generation, we were interested to establish the apical dendritic properties of L6 pyramidal neurons. We measured active and passive properties of the apical dendrites of L6 pyramidal neurons in the somatosensory region of rat cortical slices using dual patch-clamp recordings from somata and dendrites and calcium imaging. We found that L6 pyramidal neurons share many fundamental dendritic properties with other neocortical pyramidal neurons, including the generation of local dendritic spikes under the control of dendritic inhibition, voltage-dependent support of backpropagating action potentials, timing-dependent dendritic integration, distally located I-h channels, frequency-dependent Ca2+ spike activation, and NMDA spike electrogenesis in the distal apical dendrite. The results suggest that L6 pyramidal neurons integrate synaptic inputs in layer 4 similar to the way other neocortical pyramidal neurons integrate input to layer 1. Thus, L6 pyramidal neurons can perform a similar associational task operating on inputs arriving at the granular and subgranular layers.