Haufler Darrell, Pare Denis
Center for Molecular and Behavioral Neuroscience, Rutgers State University, Newark, New Jersey.
Center for Molecular and Behavioral Neuroscience, Rutgers State University, Newark, New Jersey
J Neurophysiol. 2014 Jul 1;112(1):110-9. doi: 10.1152/jn.00107.2014. Epub 2014 Apr 9.
Previously, it was reported that various cortical and subcortical structures display high-frequency local field potential (LFP) oscillations in the 110- to 160-Hz range (HFOs), distinct from sharp-wave ripples. In the present study, we characterize HFOs in the extended amygdala. Rats were implanted with tetrode bundles in the bed nucleus of the stria terminalis (BNST), central amygdala (CeA), as well as adjacent regions (pallidum, caudate-putamen, and lateral septum). At all recorded sites, HFO power showed a systematic dependence on behavioral state: highest during quiet wakefulness, intermediate during paradoxical sleep, and lowest during active waking or slow-wave sleep. CO2 asphyxiation as well as anesthesia with isoflurane or urethane abolished HFOs. HFOs stood out relative to all other fast-frequency LFP components because they were highly coherent between distant sites of the extended amygdala, ipsi- and contralaterally. HFOs affected neuronal firing in two ways: firing rate could vary as a function of HFO power (rate modulation) or HFOs could entrain firing on a cycle-to-cycle basis (phase modulation). The incidence of phase-modulated neurons was about twice higher in BNST and CeA (20-40%) than in adjacent regions (≤8%). Among BNST and CeA neurons, many more were phase-modulated than rate-modulated, although about half of the latter were also phase-modulated. Overall, these results indicate that HFOs entrain the activity of a high proportion of neurons in the extended amygdala. A major challenge for future studies will be to identify the mechanisms supporting the high coherence of HFOs within and across hemispheres.
此前有报道称，各种皮质和皮质下结构会出现频率在110至160赫兹范围内的高频局部场电位（LFP）振荡（HFOs），这与尖波涟漪不同。在本研究中，我们对扩展杏仁核中的HFOs进行了特征描述。将大鼠的四极束植入终纹床核（BNST）、中央杏仁核（CeA）以及相邻区域（苍白球、尾状核-壳核和外侧隔）。在所有记录部位，HFO功率显示出对行为状态的系统性依赖：在安静觉醒时最高，在异相睡眠时居中，在主动觉醒或慢波睡眠时最低。二氧化碳窒息以及异氟烷或氨基甲酸乙酯麻醉会消除HFOs。HFOs相对于所有其他高频LFP成分表现突出，因为它们在扩展杏仁核的远距离部位之间，同侧和对侧都具有高度的相干性。HFOs以两种方式影响神经元放电：放电率可作为HFO功率的函数而变化（速率调制），或者HFOs可在逐个周期的基础上夹带放电（相位调制）。相位调制神经元的发生率在BNST和CeA中（20 - 40%）比在相邻区域（≤8%）高出约两倍。在BNST和CeA神经元中，相位调制的神经元比速率调制的神经元多得多，尽管后者约有一半也存在相位调制。总体而言，这些结果表明HFOs夹带了扩展杏仁核中很大比例神经元的活动。未来研究的一个主要挑战将是确定支持HFOs在半球内和半球间高度相干的机制。
