Eguia Manuel C, Garcia Guadalupe C, Romano Sebastian A
Universidad Nacional de Quilmes, Laboratorio de Acústica y Percepción Sonora, RS Peña 352, Bernal, Buenos Aires, Argentina.
J Physiol Paris. 2010 May-Sep;104(3-4):118-27. doi: 10.1016/j.jphysparis.2009.11.014. Epub 2009 Nov 26.
Encoding of amplitude modulated (AM) acoustical signals is one of the most compelling tasks for the mammalian auditory system: environmental sounds, after being filtered and transduced by the cochlea, become narrowband AM signals. Despite much experimental work dedicated to the comprehension of auditory system extraction and encoding of AM information, the neural mechanisms underlying this remarkable feature are far from being understood (Joris et al., 2004). One of the most accepted theories for this processing is the existence of a periodotopic organization (based on temporal information) across the more studied tonotopic axis (Frisina et al., 1990b). In this work, we will review some recent advances in the study of the mechanisms involved in neural processing of AM sounds, and propose an integrated model that runs from the external ear, through the cochlea and the auditory nerve, up to a sub-circuit of the cochlear nucleus (the first processing unit in the central auditory system). We will show that varying the amount of inhibition in our model we can obtain a range of best modulation frequencies (BMF) in some principal cells of the cochlear nucleus. This could be a basis for a synchronicity based, low-level periodotopic organization.
对哺乳动物听觉系统而言，对调幅（AM）声学信号进行编码是最引人关注的任务之一：环境声音经耳蜗滤波和转换后，会变成窄带调幅信号。尽管已有大量实验致力于理解听觉系统对调幅信息的提取和编码，但这一显著特征背后的神经机制仍远未明晰（乔里斯等人，2004年）。对于这种处理过程，最被广泛接受的理论之一是，在研究较多的音调定位轴上存在基于时间信息的周期定位组织（弗里西纳等人，1990年b）。在这项工作中，我们将回顾调幅声音神经处理机制研究的一些最新进展，并提出一个综合模型，该模型涵盖从外耳开始，经耳蜗和听神经，直至耳蜗核的一个子回路（中枢听觉系统中的第一个处理单元）。我们将表明，通过改变模型中的抑制量，我们可以在耳蜗核的一些主要细胞中获得一系列最佳调制频率（BMF）。这可能是基于同步性的低层次周期定位组织的基础。
