摘要
本文建立了估计ISI概率密度函数的标准化ISI直方图和分布参数拟合方法,对34例猫体感皮层神经元自发和诱发放电活动进行了统计分析.
The mathematical methods of normalized ISI histogram for estimating pdf of ISIs of spike trains and its distribution parameter fitting are developed. The methods have been realized on APPLE II microcomputer and used to analyse the statistical properties of the spontaneous and driven activities of 34 neurons in somatosensory cortex of cats. Stimulus parameters for stimulating peripherally the contralateral saphenous nerve are 1.6 sec. interval, 0.2ms duration, and 20v of voltage. The unit activities are recorded in waking state by glass micro-electrode then stored and calculated on a APPLE II microcomputer. We have found that the ISI distribution can be divided into two parts, short ISIs and longer ISIs, according to their statistical features. The short ISIs usually obey typical exponential distribution with the parameter lambda being 9.16 ± 3.5ms (m ± sd). The pdf peak value of short ISIs is 0.0588±0.0064. Both the lambda and pdf peak values are not affected by the ISI means (firing rates) or peripheral stimulation, whereas the peak values of short ISIs and lambda have linear negative correlation, suggesting that the distribution function of short ISIs may be a constant. The distribution of longer ISIs is affected by the ISImeans and stimulation, exhibiting larger pdf peak values with normal distribution approximated at higher firing rate or small values with scattered distribution at lower firing rate. Peripheral stimulation causes the pdf peak values of longer ISIs obviously larger (p<0.005) (the mean of pdf maximum peak value of longer ISIs is 0.0023 ± 0.0012 (spontaneous)), but the pdf peak interval length is not affected (p<0.5) (the mean is 251.03±95.27ms (sp)), indicating a variable longer ISI peak value and intrinsic constant length. These results suggest that the statistical properties of longer and short ISIs are not similar, and they may represent different information processing mechanisms of neurons.
出处
《生物物理学报》
CAS
CSCD
北大核心
1989年第2期119-125,共7页
Acta Biophysica Sinica