Exploratory whisking by rat is not phase locked to the hippocampal theta rhythm
Exploratory whisking by rat is not phase locked to the hippocampal theta rhythm
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DOI：
10.1523/jneurosci.0190-06.2006
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发表时间：
2006-06-14
影响因子：
5.3
通讯作者：
Kleinfeld, David
中科院分区：
文献类型：
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作者：
Berg, Rune W.;Whitmer, Diane;Kleinfeld, David
大鼠海马体中的电活动具有较强的6-9 Hz节律，称为theta节律。探索性搅拌，即，大鼠触须获取触觉信息的节律性运动发生在与θ节律相同的频率范围内，并提供了一个模型系统来检查θ节律和主动感觉运动之间的关系。特别是，它已被假定，这两个节奏是锁相作为同步的感觉和海马处理的手段。我们在训练过在空气中搅拌的老鼠身上测试了这一假设。通过海马体中的场电极测量θ活动，并通过肌震颤肌电图测量搅拌。我们计算了这两个信号之间的频谱相干性，作为量化锁相程度的一种手段。首先，我们发现，具有高一致性的时期的比例并不显著大于偶然预期的比例（8只动物中的7只，作为种群平均值）。其次，我们发现试验平均相干性低（相干性，< 0.1），并且作为所有动物的平均值，在统计上不显著。我们进一步询问θ节律的强度是否与搅拌的强度相关，而与缺乏逐周期连贯性无关。我们观察到相关性很弱且不显著（8只动物中的6只，作为群体平均值）。我们的结论是，拂动和θ节律之间没有关系，至少当动物在空气中拂动时是这样。
The rat has a strong 6-9 Hz rhythm of electrical activity in the hippocampus, known as the theta rhythm. Exploratory whisking, i.e., the rhythmic movement of the rat's vibrissas to acquire tactile information, occurs within the same frequency range as the theta rhythm and provides a model system to examine the relationship between theta rhythm and active sensory movements. In particular, it has been postulated that these two rhythms are phase locked as a means to synchronize sensory and hippocampal processing. We tested this hypothesis in rats trained to whisk in air. Theta activity was measured via field electrodes in the hippocampus, and whisking was measured via the mystacial electromyogram. We calculated the spectral coherence between these two signals as a means to quantify the extent of phase locking. First, we found that the fraction of epochs with high coherence is not significantly greater than that expected by chance (seven of eight animals and as a population average). Second, we found that the trial-averaged coherence is low (coherence, < 0.1) and, as an average across all animals, statistically insignificant. We further asked whether the strength of the theta rhythm correlated with that of whisking, independent of the lack of cycle-by-cycle coherence. We observe that the correlation is weak and insignificant (six of eight animals and as a population average). We conclude that there is no relationship between the whisking and theta rhythms, at least when animals whisk in air.