Partial tripolar cochlear implant stimulation: Spread of excitation and forward masking in the inferior colliculus
Partial tripolar cochlear implant stimulation: Spread of excitation and forward masking in the inferior colliculus
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DOI：
10.1016/j.heares.2010.08.006
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发表时间：
2010-12-01
期刊：
影响因子：
2.8
通讯作者：
Middlebrooks, John C.
中科院分区：
文献类型：
--
作者：
Bierer, Julie Arenberg;Bierer, Steven M.;Middlebrooks, John C.
本研究探讨了神经活动的模式，响应于单一的双相电脉冲，单独提出或以下的前向掩蔽脉冲串，由人工耳蜗植入。在氯胺酮/甲苯噻嗪麻醉的豚鼠中，沿下丘中央核（ICC）的音调定位轴进行沿着记录。使用部分三极电极配置，其提供了一种系统的方法来改变单极（宽）和三极（窄）极端之间ICC激活的张力分布范围，同时保持相同的激活峰值。前掩蔽范例由200 ms掩蔽脉冲序列（每秒1017个脉冲）组成，10 ms后由单脉冲探针刺激组成;探针的电流分数设置为0（单极）、1（三极）或0.5（混合），掩蔽的分数固定为0.5。前向掩蔽调谐配置文件是从掩蔽电流的量所需的只是抑制由固定水平的探针产生的活动。这些配置文件更清晰的探头配置，近似的神经活动引起的单（非掩蔽）脉冲的模式。这一结果有助于弥合先前在动物身上的发现与最近的心理物理学数据之间的差距。(C)2010 Elsevier BV保留所有权利。
This study examines patterns of neural activity in response to single biphasic electrical pulses, presented alone or following a forward masking pulse train, delivered by a cochlear implant. Recordings were made along the tonotopic axis of the central nucleus of the inferior colliculus (ICC) in ketamine/xylazine anesthetized guinea pigs. The partial tripolar electrode configuration was used, which provided a systematic way to vary the tonotopic extent of ICC activation between monopolar (broad) and tripolar (narrow) extremes while maintaining the same peak of activation. The forward masking paradigm consisted of a 200 ms masker pulse train (1017 pulses per second) followed 10 ms later by a single-pulse probe stimulus; the current fraction of the probe was set to 0 (monopolar), 1 (tripolar), or 0.5 (hybrid), and the fraction of the masker was fixed at 0.5. Forward masking tuning profiles were derived from the amount of masking current required to just suppress the activity produced by a fixed-level probe. These profiles were sharper for more focused probe configurations, approximating the pattern of neural activity elicited by single (non-masked) pulses. The result helps to bridge the gap between previous findings in animals and recent psychophysical data. (C) 2010 Elsevier B.V. All rights reserved.