Bimodal stimulus timing-dependent plasticity in primary auditory cortex is altered after noise exposure with and without tinnitus
Bimodal stimulus timing-dependent plasticity in primary auditory cortex is altered after noise exposure with and without tinnitus
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DOI：
10.1152/jn.00319.2015
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发表时间：
2015-12-01
影响因子：
2.5
通讯作者：
Shore, Susan E.
中科院分区：
文献类型：
--
作者：
Basura, Gregory J.;Koehler, Seth D.;Shore, Susan E.
中枢听觉回路受到躯体感觉系统的影响，这种关系可能是耳鸣产生的基础。在豚鼠耳蜗背侧核（DCN），配对三叉神经脊束核（Sp5）刺激与特定的时间间隔和顺序的音调促进或抑制随后的音调诱发的神经反应，反映尖峰时间依赖性可塑性（STDP）。此外，噪声引起的耳鸣后，双峰反应DCN从赫布转移到反赫布定时规则与较少的离散时间窗口，提示双峰可塑性耳鸣的作用。在这里，我们的目的是确定多感觉STDP原则，如DCN也存在于初级听觉皮层（A1），以及它们是否会随着噪声引起的耳鸣而改变。在双峰刺激之前和之后15分钟记录音调诱发的和自发的神经反应，双峰刺激的间隔和顺序是随机的。音调诱发和自发放电率的双峰刺激的间隔和顺序的影响，并在假控制赫比样的定时规则占主导地位，在DCN中看到。在有和没有耳鸣的噪声暴露动物中，时间规则从假对照中发现的规则转向了更多的反赫布规则。只有那些有耳鸣证据的动物表现出自发放电率增加，这是A1耳鸣的神经生理学相关性。总之，这些研究结果表明，双峰可塑性在A1噪声损伤后也很明显，可能对耳鸣的产生和整个中枢听觉回路的治疗干预有影响。
Central auditory circuits are influenced by the somatosensory system, a relationship that may underlie tinnitus generation. In the guinea pig dorsal cochlear nucleus (DCN), pairing spinal trigeminal nucleus (Sp5) stimulation with tones at specific intervals and orders facilitated or suppressed subsequent tone-evoked neural responses, reflecting spike timing-dependent plasticity (STDP). Furthermore, after noise-induced tinnitus, bimodal responses in DCN were shifted from Hebbian to anti-Hebbian timing rules with less discrete temporal windows, suggesting a role for bimodal plasticity in tinnitus. Here, we aimed to determine if multisensory STDP principles like those in DCN also exist in primary auditory cortex (A1), and whether they change following noise-induced tinnitus. Tone-evoked and spontaneous neural responses were recorded before and 15 min after bimodal stimulation in which the intervals and orders of auditory-somatosensory stimuli were randomized. Tone-evoked and spontaneous firing rates were influenced by the interval and order of the bimodal stimuli, and in sham-controls Hebbian-like timing rules predominated as was seen in DCN. In noise-exposed animals with and without tinnitus, timing rules shifted away from those found in sham-controls to more anti-Hebbian rules. Only those animals with evidence of tinnitus showed increased spontaneous firing rates, a purported neurophysiological correlate of tinnitus in A1. Together, these findings suggest that bimodal plasticity is also evident in A1 following noise damage and may have implications for tinnitus generation and therapeutic intervention across the central auditory circuit.