大脑的神经元通过电信号相互交流。外部刺激， 如图像、声音、自身运动首先被感觉神经元检测和编码，然后通过电信号传送给更高级区域的神经元进行加工处理，再通过电信号传送到大脑高级区域。大脑能根据这些输入信息做出判断和决定。 解读这些复杂的电信号是脑科学研究的重要前沿， 也是揭开神秘奇妙的大脑奥妙的关键所在。解读大脑电信号对诊断和治疗神经疾病和心理疾病具有重要意义。 如果我们知道这些电信号表征什么，我们就非常容易基于电信号来诊断脑疾病，也能够通过人机接口来帮助残疾人恢复身体功能。

科学家正致力于解读神经元信号。最近，华盛顿大学医学院的刘胜博士等神经科学家首次运用信号侦测理论对前庭神经核的神经细胞电信号进行解读。他们用猴子做模式生物，报道了前庭神经核的神经细胞的方向区分能力，发现大部分神经元的方向区分能力比猴子和人能区分能力差，只有一小部分的神经元的方向区分能力能达到猴子和人的精度。他们还发现细胞在前后运动方向比侧向有更好的区分精度，时间对解码电信号有非常重要的影响，太短的时间不利于信息的整合，从而导致比较差的方向区分能力。对前庭神神经元信号的解读有助于我们理解神经信息编码，有助于诊断和治疗前庭疾病。该论文在《神经科学杂志》（The Journal of Neuroscience）上发表。

    参考文献：Liu S, Yakusheva T, Deangelis GC, Angelaki DE. (2010) Direction discrimination thresholds of vestibular and cerebellar nuclei neurons. J. Neurosci. 30: 439-448

Direction discrimination thresholds of vestibular and cerebellar nuclei neurons
Liu S, Yakusheva T, Deangelis GC, Angelaki DE.

Department of Neurobiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA.

To understand the roles of the vestibular system in perceptual detection and discrimination of self-motion, it is critical to account for response variability in computing the sensitivity of vestibular neurons. Here we study responses of neurons with no eye movement sensitivity in the vestibular (VN) and rostral fastigial nuclei (FN) using high-frequency (2 Hz) oscillatory translational motion stimuli. The axis of translation (i.e., heading) varied slowly (1 degrees /s) in the horizontal plane as the animal was translated back and forth. Signal detection theory was used to compute the threshold sensitivity of VN/FN neurons for discriminating small variations in heading around all possible directions of translation. Across the population, minimum heading discrimination thresholds averaged 16.6 degrees +/- 1 degrees SE for FN neurons and 15.3 degrees +/- 2.2 degrees SE for VN neurons, severalfold larger than perceptual thresholds for heading discrimination. In line with previous studies and theoretical predictions, maximum discriminability was observed for directions where firing rate changed steeply as a function of heading, which occurs at headings approximately perpendicular to the maximum response direction. Forward/backward heading thresholds tended to be lower than lateral motion thresholds, and the ratio of lateral over forward heading thresholds averaged 2.2 +/- 6.1 (geometric mean +/- SD) for FN neurons and 1.1 +/- 4.4 for VN neurons. Our findings suggest that substantial pooling and/or selective decoding of vestibular signals from the vestibular and deep cerebellar nuclei may be important components of further processing. Such a characterization of neural sensitivity is critical for understanding how early stages of vestibular processing limit behavioral performance.

PMID: 20071508 [PubMed - indexed for MEDLINE]