Cellular Neuroscience, IST Austria (Institute of Science and Technology Austria), Am Campus 1, 3400 Klosterneuburg, Austria.
Cellular Neuroscience, IST Austria (Institute of Science and Technology Austria), Am Campus 1, 3400 Klosterneuburg, Austria.
Neuron. 2020 Sep 23;107(6):1212-1225.e7. doi: 10.1016/j.neuron.2020.07.006. Epub 2020 Aug 6.
Dentate gyrus granule cells (GCs) connect the entorhinal cortex to the hippocampal CA3 region, but how they process spatial information remains enigmatic. To examine the role of GCs in spatial coding, we measured excitatory postsynaptic potentials (EPSPs) and action potentials (APs) in head-fixed mice running on a linear belt. Intracellular recording from morphologically identified GCs revealed that most cells were active, but activity level varied over a wide range. Whereas only ∼5% of GCs showed spatially tuned spiking, ∼50% received spatially tuned input. Thus, the GC population broadly encodes spatial information, but only a subset relays this information to the CA3 network. Fourier analysis indicated that GCs received conjunctive place-grid-like synaptic input, suggesting code conversion in single neurons. GC firing was correlated with dendritic complexity and intrinsic excitability, but not extrinsic excitatory input or dendritic cable properties. Thus, functional maturation may control input-output transformation and spatial code conversion.
齿状回颗粒细胞（GCs）将内嗅皮层连接到海马 CA3 区，但它们如何处理空间信息仍然是个谜。为了研究 GCs 在空间编码中的作用，我们在头部固定的小鼠在线性皮带上跑动时测量了兴奋性突触后电位（EPSP）和动作电位（AP）。从形态上鉴定的 GCs 进行细胞内记录显示，大多数细胞是活跃的，但活性水平在很大范围内变化。虽然只有约 5%的 GCs 表现出空间调谐的放电，但约 50%的 GC 接收空间调谐的输入。因此，GC 群体广泛编码空间信息，但只有一部分将此信息传递给 CA3 网络。傅里叶分析表明，GC 接收连接的位置网格样突触输入，这表明在单个神经元中进行代码转换。GC 的放电与树突复杂性和内在兴奋性相关，但与外在兴奋性输入或树突电缆特性无关。因此，功能成熟可能控制输入-输出转换和空间代码转换。
