Inui Koji, Takeuchi Nobuyuki, Sugiyama Shunsuke, Motomura Eishi, Nishihara Makoto
Institute for Developmental Research, Aichi Human Service Center, Kasugai, Japan.
Department of Integrative Physiology, National Institute for Physiological Sciences, Okazaki, Japan.
PLoS One. 2018 Jan 3;13(1):e0190481. doi: 10.1371/journal.pone.0190481. eCollection 2018.
Despite their essential roles in signal processing in the brain, the functions of interneurons currently remain unclear in humans. We recently developed a method using the prepulse inhibition of sensory evoked cortical responses for functional measurements of interneurons. When a sensory feature is abruptly changed in a continuous sensory stimulus, change-related cortical responses are recorded using MEG. By inserting a weak change stimulus (prepulse) before the test change stimulus, it is possible to observe the inhibition of the test response. By manipulating the prepulse-test interval (PTI), several peaks appear in inhibition, suggesting the existence of temporally distinct mechanisms. We herein attempted to separate these components through the oral administration of diazepam and baclofen. The test stimulus and prepulse were an abrupt increase in sound pressure in a continuous click train of 10 and 5 dB, respectively. The results obtained showed that the inhibition at PTIs of 10 and 20 ms was significantly greater with diazepam than with the placebo administration, suggesting increased GABAA-mediated inhibition. Baclofen decreased inhibition at PTIs of 40 and 50 ms, which may have been due to the activation of GABAB autoreceptors. Therefore, the present study separated at least two inhibitory mechanisms pharmacologically.
尽管中间神经元在大脑信号处理中起着重要作用，但其在人类中的功能目前仍不清楚。我们最近开发了一种利用感觉诱发皮质反应的预脉冲抑制来对中间神经元进行功能测量的方法。当在连续的感觉刺激中感觉特征突然改变时，使用脑磁图（MEG）记录与变化相关的皮质反应。通过在测试变化刺激之前插入一个微弱的变化刺激（预脉冲），可以观察到对测试反应的抑制。通过操纵预脉冲 - 测试间隔（PTI），抑制中会出现几个峰值，这表明存在时间上不同的机制。我们在此试图通过口服地西泮和巴氯芬来分离这些成分。测试刺激和预脉冲分别是在持续的10次和5分贝的滴答声序列中声压的突然增加。获得的结果表明，与安慰剂给药相比，地西泮在10和20毫秒的PTI时的抑制作用明显更大，这表明GABAA介导的抑制作用增强。巴氯芬降低了40和50毫秒PTI时的抑制作用,这可能是由于GABAB自身受体的激活。因此，本研究从药理学上分离了至少两种抑制机制。
