State-Dependent Changes in Cortical Gain Control as Measured by Auditory Evoked Responses to Varying Intensity Stimuli
State-Dependent Changes in Cortical Gain Control as Measured by Auditory Evoked Responses to Varying Intensity Stimuli
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DOI：
10.5665/sleep.1392
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发表时间：
2011-11-01
期刊：
影响因子：
5.6
通讯作者：
Rector, David M.
中科院分区：
文献类型：
--
作者：
Phillips, Derrick J.;Schei, Jennifer L.;Rector, David M.
研究目的：听觉诱发电位(AEP)成分对应于听觉通路中脑结构的顺序激活，揭示了感觉加工过程中的神经活动。为了研究不同大脑结构中刺激强度响应曲线的状态依赖调制，我们评估了刺激强度和状态的AEP成分。设计：我们在成年雌性SD大鼠(N=6)身上植入电极来测量EEG、EKG和EMG。24小时内给予50~75DBA的间歇性听觉刺激(S 6~12次)。将数据解析为2-S历元，并对觉醒/睡眠状态进行评分。结果：觉醒时所有听觉诱发电位成分的波幅均随着刺激强度的增加而增加。然而，在安静睡眠中，只有早潜伏期反应(ELR)表现出这种关系，而中潜伏期反应(MLR)在75DBA强度最高时增加，而晚潜伏期反应(LLR)在所测试的刺激强度之间没有显著变化。在快速眼动睡眠(REM)中，ELR和LLR均增加，与清醒时相似，但MLR严重减弱。结论：刺激强度和相应的AEP反应曲线与脑结构和睡眠状态有关。较低的大脑结构在睡眠期间维持刺激强度和神经反应关系。在大脑皮层中没有观察到这种关系，这意味着刺激强度编码的状态依赖于修改。由于AEP的幅度不受睡眠期间刺激强度的调节，因此75/50DBA刺激组合之间的差异可以用来比单独的强度更好地确定状态。
Study Objectives: Auditory evoked potential (AEP) components correspond to sequential activation of brain structures within the auditory pathway and reveal neural activity during sensory processing. To investigate state-dependent modulation of stimulus intensity response profiles within different brain structures, we assessed AEP components across both stimulus intensity and state.Design: We implanted adult female Sprague-Dawley rats (N = 6) with electrodes to measure EEG, EKG, and EMG. Intermittent auditory stimuli (6-12 s) varying from 50 to 75 dBa were delivered over a 24-h period. Data were parsed into 2-s epochs and scored for wake/sleep state.Results: All AEP components increased in amplitude with increased stimulus intensity during wake. During quiet sleep, however, only the early latency response (ELR) showed this relationship, while the middle latency response (MLR) increased at the highest 75 dBa intensity, and the late latency response (LLR) showed no significant change across the stimulus intensities tested. During rapid eye movement sleep (REM), both ELR and LLR increased, similar to wake, but MLR was severely attenuated.Conclusions: Stimulation intensity and the corresponding AEP response profile were dependent on both brain structure and sleep state. Lower brain structures maintained stimulus intensity and neural response relationships during sleep. This relationship was not observed in the cortex, implying state-dependent modification of stimulus intensity coding. Since AEP amplitude is not modulated by stimulus intensity during sleep, differences between paired 75/50 dBa stimuli could be used to determine state better than individual intensities.