ENCODING TIMING AND INTENSITY IN THE VENTRAL COCHLEAR NUCLEUS OF THE CAT
ENCODING TIMING AND INTENSITY IN THE VENTRAL COCHLEAR NUCLEUS OF THE CAT
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DOI：
10.1152/jn.1986.56.2.261
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发表时间：
1986-08-01
影响因子：
2.5
通讯作者：
SMITH, PH
中科院分区：
文献类型：
--
作者：
RHODE, WS;SMITH, PH
耳蜗腹核神经元的生理反应特性具有许多不同于作为这些神经元的主要激活来源的典型听神经反应的特征。这些新出现的特征是听神经输入在核内不同细胞类型的胞体和树突上的不同分布的结果；不同类型细胞的固有膜特性导致不同细胞类型对相同输入的不同反应；以及对不同细胞类型的次级兴奋性和抑制性输入。用高阻抗玻璃微电极记录细胞内和细胞外隔离良好的单位。单位的特征是它们对短音调的时间反应，速率与强度的关系，以及反应区域。主要反应模式为起始型、斩断型和原发型。首发单位的特征是对特征频率的音调做出及时的第一次尖峰反应。对于低于1 kHz的频率，起效单位可以比它们的听神经输入更精确地进入刺激频率。这意味着起始单位接受来自许多听神经纤维的汇聚输入。起效单位分为三个子类别：OC、OL和OI。OC单元具有极宽的动态范围和低频选择性。有些能够在高强度下维持800个尖峰的射速/S。在耳蜗核中，它们具有最小的第一峰潜伏期的标准差和变异系数。OC单位是编码强度的候选单位。OI和OL单位与OC单位的不同之处在于，它们的动态范围和频率选择性范围与听神经纤维非常相似。它们在稳态射击速度上各不相同；OI单位主要在一个音调开始时开火。OI单元与OL单元的不同之处还在于它们更喜欢从低到高方向的频率扫描。初级类带槽(PLN)单位也会对音调做出及时的第一次尖峰反应。它们与起病细胞的不同之处在于，起病峰值并不总是那么精确，而自发频率更高。PLN单位与听神经纤维的自发放电率和饱和放电率的比较表明，PLN单位接受1~4个听神经纤维输入。当直升机单位受到声音的刺激时，它们会持续地、有规律地开火。
Physiological response properties of neurons in the ventral cochlear nucleus have a variety of features that are substantially different from the stereotypical auditory nerve responses that serve as the principal source of activation for these neurons. These emergent features are the result of the varying distribution of auditory nerve inputs on the soma and dendrites of the various cell types within the nucleus; the intrinsic membrane characteristics of the various cell types causing different responses to the same input in different cell types; and secondary excitatory and inhibitory inputs to different cell types. Well-isolated units were recorded with high-impedance glass microelectrodes, both intracellularly and extracellularly. Units were characterized by their temporal response to short tones, rate vs. intensity relation, and response areas. The principal response patterns were onset, chopper, and primary-like. Onset units are characterized by a well-timed first spike in response to tones at the characteristic frequency. For frequencies less than 1 kHz, onset units can entrain to the stimulus frequency with greater precision than their auditory nerve inputs. This implies that onset units receive converging inputs from a number of auditory nerve fibers. Onset units are divided into three subcategories, OC, OL, and OI. OC units have extraordinarily wide dynamic ranges and low-frequency selectivity. Some are capable of sustaining firing rates of 800 spikes/s at high intensities. They have the smallest standard deviation and coefficient of variation of the first spike latency of any cells in the cochlear nuclei. OC units are candidates for encoding intensity. OI and OL units differ from OC units in that they have dynamic ranges and frequency selectivity ranges much like those of auditory nerve fibers. They differ from one another in their steady-state firing rates; OI units fire mainly at the onset of a tone. OI units also differ from OL units in that they prefer frequency sweeps in the low to high direction. Primary-like-with-notch (PLN) units also respond to tones with a well-timed first spike. They differ from onset cells in that the onset peak is not always as precise as the spontaneous rate is higher. A comparison of spontaneous firing rate and saturation firing rate of PLN units with auditory nerve fibers suggest that PLN units receive one to four auditory nerve fiber inputs. Chopper units fire in a sustained regular manner when they are excited by sound.(ABSTRACT TRUNCATED AT 400 WORDS)