Hu Hua, Vervaeke Koen, Graham Lyle J, Storm Johan F
Department of Physiology at Institute of Basal Medicine and Centre for Molecular Biology and Neuroscience, University of Oslo, N-0317 Oslo, Norway.
J Neurosci. 2009 Nov 18;29(46):14472-83. doi: 10.1523/JNEUROSCI.0187-09.2009.
Synaptic input to a neuron may undergo various filtering steps, both locally and during transmission to the soma. Using simultaneous whole-cell recordings from soma and apical dendrites from rat CA1 hippocampal pyramidal cells, and biophysically detailed modeling, we found two complementary resonance (bandpass) filters of subthreshold voltage signals. Both filters favor signals in the theta (3-12 Hz) frequency range, but have opposite location, direction, and voltage dependencies: (1) dendritic H-resonance, caused by h/HCN-channels, filters signals propagating from soma to dendrite when the membrane potential is close to rest; and (2) somatic M-resonance, caused by M/Kv7/KCNQ and persistent Na(+) (NaP) channels, filters signals propagating from dendrite to soma when the membrane potential approaches spike threshold. Hippocampal pyramidal cells participate in theta network oscillations during behavior, and we suggest that that these dual, polarized theta resonance mechanisms may convey voltage-dependent tuning of theta-mediated neural coding in the entorhinal/hippocampal system during locomotion, spatial navigation, memory, and sleep.
神经元的突触输入在局部以及向胞体的传输过程中可能会经历各种滤波步骤。通过对大鼠CA1海马锥体神经元的胞体和顶端树突进行同步全细胞记录，并结合生物物理细节建模，我们发现了阈下电压信号的两种互补共振（带通）滤波器。这两种滤波器都偏好θ（3 - 12赫兹）频率范围内的信号，但在位置、方向和电压依赖性方面相反：（1）由h/HCN通道引起的树突H共振，在膜电位接近静息时，对从胞体向树突传播的信号进行滤波；（2）由M/Kv7/KCNQ和持续性钠（NaP）通道引起的胞体M共振，在膜电位接近动作电位阈值时，对从树突向胞体传播的信号进行滤波。海马锥体神经元在行为过程中参与θ网络振荡，我们认为这些双重、极化的θ共振机制可能在运动、空间导航、记忆和睡眠期间，在内嗅/海马系统中传递与电压相关的θ介导神经编码调谐。
