Improvement of phase information at low sound frequency in nucleus magnocellularis of the chicken
Improvement of phase information at low sound frequency in nucleus magnocellularis of the chicken
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DOI：
10.1152/jn.00916.2005
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发表时间：
2006-08-01
影响因子：
2.5
通讯作者：
Ohmori, Harunori
中科院分区：
文献类型：
--
作者：
Fukui, Iwao;Sato, Tatsuo;Ohmori, Harunori
大细胞核（NM）是鸟类耳蜗核的亚核之一，具有从听觉神经纤维（ANFs）中提取声音的时间信息的作用。神经元在突触传递和膜兴奋性上沿张力异位轴变化，是中高特征频率（CF）区域的高保真中继神经元。在这里，我们比较了anf和NM神经元在体内的放电特性，发现在高但不接近阈值的强度下，在CF区域< 500 Hz的NM中，峰值放电比anf中更锁相。此外，与ANF相比，NM在一个声刺激周期内出现的多个尖峰减少了，矢量强度更高。在低CF神经元中，小EPSCs的体外研究结果与NM的锁相放电特性的改进进行了讨论（Fukui和Ohmori 2004）。结果表明，NM神经元不是简单的低CF区中继神经元，而是单耳突触输入的重合检测器，提高了脉冲放电与听觉输入的同步性。
Nucleus magnocellularis (NM) is one of the subnuclei of the avian cochlear nucleus and has a role of extracting the temporal information of sound from the auditory nerve fibers (ANFs). Neurons in NM are varied along the tonotopic axis in synaptic transmission and membrane excitability and are high-fidelity relay neurons at the high to middle characteristic frequency (CF) regions. Here we have compared the firing properties between ANFs and NM neurons in vivo and found that at high but not near threshold intensities, spike firings are more phase-locked in NM than in ANFs in the CF region < 500 Hz. Moreover, NM shows reduced occurrence of multiple spikes within one cycle of sound stimuli and higher vector strength than ANF. The improved phase-locked firing nature of NM is discussed in relation to the in vitro findings of small EPSCs in the low CF neurons (Fukui and Ohmori 2004). It is concluded that NM neurons are not simple relay neurons in the low CF region but are coincidence detectors of monoaural synaptic inputs that improve the synchronization of spike firing to auditory inputs.