Lenz F A, Tasker R R, Kwan H C, Schnider S, Kwong R, Murayama Y, Dostrovsky J O, Murphy J T
Division of Neurosurgery, Toronto General Hospital, Canada.
J Neurosci. 1988 Mar;8(3):754-64. doi: 10.1523/JNEUROSCI.08-03-00754.1988.
Although cells firing at tremor frequency, called "tremor cells" (Guiot et al., 1962), have often been recorded in the thalamus of parkinsonian patients, the extent of correlation between these spike trains and tremor has rarely been assessed quantitatively. This paper describes spectral cross-correlation functions calculated between the activity of "tremor cells" and electromyogram (EMG) signals recorded from several muscles in the contralateral arm. The power occurring in the spike train at tremor frequency was described in absolute terms by the spike autopower, and in relation to the average for all spectral components by the spike autopower signal-to-noise ratio (spike autopower SNR). The probability of significant cross-correlation between the thalamic spike train and EMG at tremor frequency was assessed by the coherence at tremor frequency. Autopower spectra of the activity of many of these cells exhibited a concentration of power at tremor frequency, indicated by spike autopower SNRs as high as 18. Of the EMG signals studied, signals recorded from finger flexors were most often significantly correlated at tremor frequency. Significant correlation between the thalamic spike train and finger flexor EMG activity was found in 34% of cells analyzed. Tremor frequency coherence was significantly correlated with tremor frequency spike autopower (r = 0.46, p less than 0.0001) and spike autopower SNR (r = 0.533, p less than 0.0001). The proportion of cells with a spike autopower SNR greater than 2 that were significantly correlated with finger flexor EMG activity was greater than that of cells with a spike autopower SNR of less than 2 (p less than 0.001; chi-square). Therefore, cells exhibiting a large amount of power at tremor frequency were those best correlated with EMG activity during tremor. Some of these cells may be involved in the generation of tremor.
尽管在帕金森病患者的丘脑常常记录到以震颤频率放电的细胞，即所谓的“震颤细胞”（吉约等人，1962年），但这些脉冲序列与震颤之间的关联程度很少得到定量评估。本文描述了“震颤细胞”活动与从对侧手臂几块肌肉记录的肌电图（EMG）信号之间计算出的频谱互相关函数。震颤频率下脉冲序列中出现的功率，用脉冲自功率以绝对值描述，并用脉冲自功率信噪比（脉冲自功率SNR）相对于所有频谱成分的平均值来描述。丘脑脉冲序列与震颤频率下的EMG之间显著互相关的概率，通过震颤频率下的相干性来评估。许多这类细胞活动的自功率谱在震颤频率处呈现功率集中，脉冲自功率SNR高达18表明了这一点。在所研究的EMG信号中，从手指屈肌记录的信号在震颤频率下最常出现显著相关性。在分析的细胞中，34%发现丘脑脉冲序列与手指屈肌EMG活动之间存在显著相关性。震颤频率相干性与震颤频率脉冲自功率（r = 0.46，p小于0.0001）和脉冲自功率SNR（r = 0.533，p小于0.0001）显著相关。脉冲自功率SNR大于2且与手指屈肌EMG活动显著相关的细胞比例，高于脉冲自功率SNR小于2的细胞比例（p小于0.001；卡方检验）。因此，在震颤频率下呈现大量功率的细胞，是那些在震颤期间与EMG活动相关性最佳的细胞。其中一些细胞可能参与了震颤的产生。
