Roles of inhibition in creating complex auditory responses in the inferior colliculus: facilitated combination-sensitive neurons.
Roles of inhibition in creating complex auditory responses in the inferior colliculus: facilitated combination-sensitive neurons.
复制标题
DOI：
10.1152/jn.01152.2004
复制
发表时间：
2005-06
影响因子：
2.5
通讯作者：
K. Nataraj;J. Wenstrup
中科院分区：
文献类型：
--
作者：
K. Nataraj;J. Wenstrup
我们研究了抑制对小胡子蝙蝠下丘（IC）组合敏感神经元时间敏感易化的作用。在这些整合神经元中，对最佳频率（BF）音调的兴奋性反应被呈现在特定时间关系中的低得多的频率信号增强。大多数易化神经元（76%）表现出抑制的延迟早于或晚于延迟引起促进。在早期延迟抑制的时间是密切相关的最佳延迟的易化，但抑制的持续时间或强度的易化相互作用的影响不大。局部离子电渗应用甘氨酸（士的宁）和γ-氨基丁酸（GABA）（荷包牡丹碱，BIC）受体的拮抗剂显示，士的宁在96%的测试单位中消除了促进作用，但BIC仅在28%中消除了促进作用。这表明，易化的相互作用是在IC中创建的，并揭示了这些神经递质的不同作用。这种促进作用可能是由低频信号激活的抑制后反弹兴奋与BF诱发的兴奋的重合而产生的。不像促进，抑制在早期延迟不消除应用拮抗剂，表明起源于较低的脑干核。然而，延迟抑制比促进，如促进本身，似乎起源于IC和更多地依赖于甘氨酸比GABA能机制。由这些组合敏感神经元显示的促进和抑制相互作用在声纳回声和社会发声中编码信息。结果表明，这些复杂的反应特性是通过听觉脑干和中脑中的一系列神经相互作用而产生的。
We studied roles of inhibition on temporally sensitive facilitation in combination-sensitive neurons from the mustached bat's inferior colliculus (IC). In these integrative neurons, excitatory responses to best frequency (BF) tones are enhanced by much lower frequency signals presented in a specific temporal relationship. Most facilitated neurons (76%) showed inhibition at delays earlier than or later than the delays causing facilitation. The timing of inhibition at earlier delays was closely related to the best delay of facilitation, but the inhibition had little influence on the duration or strength of the facilitatory interaction. Local iontophoretic application of antagonists to receptors for glycine (strychnine, STRY) and gamma-aminobutyric acid (GABA) (bicuculline, BIC) showed that STRY abolished facilitation in 96% of tested units, but BIC eliminated facilitation in only 28%. This suggests that facilitatory interactions are created in IC and reveals a differential role for these neurotransmitters. The facilitation may be created by coincidence of a postinhibitory rebound excitation activated by the low-frequency signal with the BF-evoked excitation. Unlike facilitation, inhibition at earlier delays was not eliminated by application of antagonists, suggesting an origin in lower brain stem nuclei. However, inhibition at delays later than facilitation, like facilitation itself, appears to originate within IC and to be more dependent on glycinergic than GABAergic mechanisms. Facilitatory and inhibitory interactions displayed by these combination-sensitive neurons encode information within sonar echoes and social vocalizations. The results indicate that these complex response properties arise through a series of neural interactions in the auditory brain stem and midbrain.