基于直接方法估算的信息熵在局部场电位编码工作记忆中的应用  

LFPs coding working memory task via information entropy using plugin method

作　　者：司家瑞[1,2] 白文文[1] 刘迢迢[1] 黎小沛[2] 田心[1] 

机构地区：[1]天津医科大学生物医学工程学院,300070 [2]天津医科大学基础医学院

出　　处：《国际生物医学工程杂志》2015年第4期211-213,217,I0005,共5页International Journal of Biomedical Engineering

基　　金：国家百然科学基金资助项目（61401311,61301252,31300597）;天津市自然科学基金面上项目（10JCYBJC14400）;博士后基金项目（2014M561193）

摘　　要：目的研究大鼠在Y迷宫记忆过程中，责任脑区前额叶皮层记录的局部场电位的熵编码，为研究工作记忆的神经编码机制提供计算支持。方法实验数据：本研究所用的实验数据为4只SD大鼠在Y迷宫工作记忆过程和静息状态下前额叶皮层的各20次16通道局部场电位（LFPs）数据（其中10次正确，10次错误），由天津医科大学医学神经生物学实验室提供；LFPs预处理：对LFPs去除工频干扰和基线漂移；LFPs的时频分析与特征频段的提取：通过多窗口傅里叶变换，观察能量分布的主要频段，并通过带通滤波提取特征频段的场电位信号；16通道LFPs的熵编码：选取生理窗口为500ms，窗口移动步长为125ms，对LFPs数据序列加窗，计算每个滑动窗口内的熵值并平均，进而观察信息熵的变化趋势。结果LFPs时频分布表明工作记忆期间其能量主要集中在θ频段（4～12Hz）；θ频段LFPs在正确工作记忆实验中，工作记忆参考点前1s熵的平均值为0．939±0．020，显著大于静息状态的值（0．795±0．031），其差异具有统计学意义（P〈0．05）；而错误实验中工作记忆事件前后信息熵值无差别，未编码工作记忆事件。结论θ频段（4～12Hz）是工作记忆的特征频段；θ频段LFPs的熵有效地编码了工作记忆事件。Objective To investigate the entropy of local field potentials （LFPs） recorded in rat medial prefrontal cortex during a Y-maze working memory （firM） task, to provide computing support for neural coding mechanism. Methods Sixteen-channel LFPs were recorded from SD rats while they performed a Y-maze WM task. The data came from 4 rats, 20 trials （10 correct trials and 10 incorrect trials） per rat provided by laboratory of neurobiology in medicine, Tianjin Medical University. Original LFPs were preprocessed to remove 50 Hz power line noise and baseline drift. Multi-taper Fourier transform was applied to calculate spatial distributions of LFPs and band pass filter were used to extract characteristic signal. The entroy coding of 16 channel LFPs was as follows： the physiological window was set to be 500 ms, the step length of physiological window was set to be 125 ms, windows were added to LFPs data, and then LFPs entropy of each sliding window was computed and averaged to get the trend of muhichannel entropy values duringthe WM task. Results The power of θ band （4-12 Hz） in LFPs increasecL The averaged entropy value ofmuhichannel θ band LFPs in correct trials was 0.939±0.020, which were larger than those in the resting state, 0.795±0.031 （P〈0.05）. Those during wrong WM task had no significant difference, which didn＇t encode the WM task. Conclusions The principal frequency band related to WM is the θ band and LFPs entropy encodes the WM effectively.

关 键 词：SD大鼠 工作记忆 局部场电位 多窗口 熵 

分 类 号：R318[医药卫生—生物医学工程] TP183[医药卫生—基础医学]