Corticofugal feedback for collicular plasticity evoked by electric stimulation of the inferior colliculus
Corticofugal feedback for collicular plasticity evoked by electric stimulation of the inferior colliculus
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DOI：
10.1152/jn.00549.2005
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发表时间：
2005-10-01
影响因子：
2.5
通讯作者：
Suga, N
中科院分区：
文献类型：
--
作者：
Zhang, YK;Suga, N
听觉皮质的局部电刺激、30分钟的重复声刺激和听觉恐惧条件反射，每一种都会引起皮层和中脑神经元频率调谐曲线的移位[以下称为最佳频率(BF)移位]。短期的丘脑BF漂移是由皮质分离系统产生的，主要取决于记录的丘神经元和受刺激的皮质神经元之间的BF关系，或者记录的丘神经元的BF与声刺激频率之间的关系。然而，目前尚不清楚电刺激下丘是否会引起丘脑BF移位，以及如果引起丘脑BF移位是否依赖皮质分离反馈。在我们目前对觉醒的大棕色蝙蝠的研究中，我们发现，局灶性电刺激丘神经元引起位于刺激神经元附近的丘神经元的BF漂移；存在两种类型的BF漂移：向心性和离心性BF漂移，即分别向刺激神经元的BF移动和远离BF移动；这些耳丘BF移动的发展被听觉皮质的失活所阻止。我们的数据表明，由丘脑电刺激引起的丘脑BF移位(可塑性)依赖于皮质分离反馈。值得注意的是，丘脑的BF漂移也依赖于乙酰胆碱，因为已经证明，应用于IC的阿托品(M胆碱受体的拮抗剂)可以阻断丘脑BF漂移的发展。
Focal electric stimulation of the auditory cortex, 30-min repetitive acoustic stimulation, and auditory fear conditioning each evoke shifts of the frequency-tuning curves [ hereafter, best frequency (BF) shifts] of cortical and collicular neurons. The short-term collicular BF shift is produced by the corticofugal system and primarily depends on the relationship in BF between a recorded collicular and a stimulated cortical neuron or between the BF of a recorded collicular neuron and the frequency of an acoustic stimulus. However, it has been unknown whether focal electric stimulation of the inferior colliculus evokes the collicular BF shift and whether the collicular BF shift, if evoked, depends on corticofugal feedback. In our present research with the awake big brown bat, we found that focal electric stimulation of collicular neurons evoked the BF shifts of collicular neurons located near the stimulated ones; that there were two types of BF shifts: centripetal and centrifugal BF shifts, i.e., shifts toward and shifts away from the BF of stimulated neurons, respectively; and that the development of these collicular BF shifts was blocked by inactivation of the auditory cortex. Our data indicate that the collicular BF shifts ( plasticity) evoked by collicular electric stimulation depended on corticofugal feedback. It should be noted that collicular BF shifts also depend on acetylcholine because it has been demonstrated that atropine ( an antagonist of muscarinic acetylcholine receptors) applied to the IC blocks the development of collicular BF shifts.