Morphological identification of physiologically characterized afferents innervating the turtle posterior crista
Morphological identification of physiologically characterized afferents innervating the turtle posterior crista
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DOI：
10.1152/jn.2000.83.3.1202
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发表时间：
2000-03-01
影响因子：
2.5
通讯作者：
Goldberg, JM
中科院分区：
文献类型：
--
作者：
Brichta, AM;Goldberg, JM
龟背后嵴由两条半嵴组成。每个半嵴从半月形平面延伸到非感觉环面，并包括由外周区（PZ）包围的中心区（CZ）。I型和II型：毛细胞位于CZ中，并受花萼、二形和终扣传入神经支配。在PZ中仅发现II型毛细胞和终扣纤维。在半头制备物中对单元进行轴突内标记。Bouton（B）单元可以位于平面（BP）附近、环面（BT）附近或半嵴的中部（包括PZ和CZ）。放电特性的B单位不同的纵向位置在一个半嵴，但不与其周边终端的形态特征。BP单元有规律地放电，并且具有小的增益和小的相对于头部角速度的相位超前。BT单位是不规则的，并且具有较大的增益和较大的相位领先。BM单元具有中间性质。花萼（C）和二形（D）单元具有相似的放电特性，并被归入单一的带花萼（CD）类别。虽然有一个不规则的放电类似BT单位，CD单位有增益和阶段类似的BM单位。而不是任何单一的放电属性，这是放电规律性和增益或相位之间的关系，使CD单位与众不同。多元统计公式推导出一个单位的形态类（B或CD）和纵向位置仅从其放电特性。为了验证公式的使用，比较了完整动物半头轴突内或细胞外或细胞外记录的单位的放电特性。大多数B单元具有10-30尖峰/秒的背景速率。CD类别分为CD-高和CD-低单位，背景速率分别高于或低于5个峰值/秒。CD-低单元具有较低的增益和相位，并且比CD-高单元更靠近平面。在0.01-3 Hz的频率范围内，BP单元的响应动力学符合过阻尼扭摆模型。其他单位显示偏离模型，包括高频增益增加和相位领先。海龟B单位生理学上的纵向梯度类似于南极嵴的类似梯度。在许多方面，海龟CD单位的放电特性类似于哺乳动物中心区的花萼轴承单位。
The turtle posterior crista consists of two hemicristae. Each hemicrista extends from the planum semilunatum to the nonsensory torus and includes a central zone (CZ) surrounded by a peripheral zone (PZ). Type I and type II: hair cells are found in the CZ and are innervated by calyx, dimorphic and bouton afferents. Only type II hair cells and bouton fibers are found In the PZ. Units were intraaxonally labeled in a half-head preparation. Bouton (B) units could be near the planum (BP), near the torus (BT), or in midportions of a hemicrista, including the PZ and CZ. Discharge properties of B units vary with longitudinal position in a hemicrista but not with morphological features of their peripheral terminations. BP units are regularly discharging and have small gains and small phase leads re angular head velocity. BT units are irregular and have large gains and large phase leads. BM units have intermediate properties. Calyx (C) and dimorphic (D) units have similar discharge properties and were placed into a single calyx-bearing (CD) category. While having an irregular discharge resembling BT units, CD units have gains and phases similar to those of BM units. Rather than any single discharge property, it is the relation between discharge regularity and either gain or phase that makes CD units distinctive. Multivariate statistical formulas were developed to infer a unit's morphological class (B or CD) and longitudinal position solely from its discharge properties. To verify the use of the formulas, discharge properties were compared for units recorded intraaxonally or extracellularly in the half-head or extracellularly in intact animals. Most B units have background rates of 10-30 spikes/s. The CD category was separated into CD-high and CD-low units with background rates above or below 5 spikes/s, respectively. CD-low units have lower gains and phases and are located nearer the planum than CD-high units. In their response dynamics over a frequency range from 0.01-3 Hz, BP units conform to an overdamped torsion-pendulum model. Other units show departures from the model, including high-frequency gain increases and phase leads. The longitudinal gradient in the physiology of turtle B units resembles a similar gradient in the anamniote crista. In many respects, turtle CD units have discharge properties resembling those of calyx-bearing units in the mammalian central zone.