噪声对视觉信息处理的影响。

Effect of noise in processing of visual information.

作者信息

Hinrikus Hiie, Karai Deniss, Lass Jaanus, Rodina Anastassia

机构信息

Department of Biomedical Engineering, Technomedicum, Tallinn University of Technology, Ehitajate Rd 5, 19086 Tallinn, Estonia.

Department of Medical Physics, School of Medicine, University of Patras, University Campus, 265 04 Rio Patras, Greece.

出版信息

Nonlinear Biomed Phys. 2010 Jun 3;4 Suppl 1(Suppl 1):S5. doi: 10.1186/1753-4631-4-S1-S5.

DOI:10.1186/1753-4631-4-S1-S5

PMID:20522266

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC2880802/

Abstract

BACKGROUND

Information transmission and processing in the nervous system has stochastic nature. Multiple factors contribute to neuronal trial-to-trial variability. Noise and variations are introduced by the processes at the molecular and cellular level (thermal noise, channel current noise, membrane potential variations, biochemical and diffusion noise at synapses etc). The stochastic processes are affected by different physical (temperature, electromagnetic field) and chemical (drugs) factors. The aim of this study was experimental investigation of hypotheses that increase in the noise level in the brain affects processing of visual information. Change in the noise level was introduced by an external factor producing excess noise in the brain.

METHODS

An exposure to 450 MHz low-frequency modulated microwave radiation was applied to generate excess noise. Such exposure has been shown to increase diffusion, alter membrane resting potential, gating variables and intracellular Calcium efflux. Nine healthy volunteers passed the experimental protocol at the lower (without microwave) and the higher (with microwave) noise level. Two photos (visual stimuli) of unfamiliar, young male faces were presented to the subjects, one picture after another. The task was to identify later the photos from a group of six photos and to decide in which order they were presented. Each subject had a total of eight sessions at the lower and eight at the higher noise level. Each session consisted of 50 trials; altogether a subject made 800 trials, 400 at the lower and 400 at the higher noise level. Student t-test was applied for statistical evaluation of the results.

RESULTS

Correct recognition of both stimuli in the right order was better at the lower noise level. All the subjects under investigation showed higher numbers of right answers in trials at the lower noise level. Average number of correct answers from n=400 trials with microwave exposure was 50.3, without exposure 54.4, difference 7.5%, p<0.002. No difference between results at the lower and the higher noise level was revealed in the case of only partly correct or incorrect answers.

CONCLUSIONS

Our experimental results showed that introduced excess noise reduced significantly ability of the nervous system in correct processing of visual information.

摘要

背景

神经系统中的信息传递和处理具有随机性。多种因素导致神经元在不同试验间的变异性。噪声和变异性由分子和细胞水平的过程引入（热噪声、通道电流噪声、膜电位变化、突触处的生化和扩散噪声等）。随机过程受不同物理（温度、电磁场）和化学（药物）因素影响。本研究的目的是通过实验研究大脑中噪声水平增加会影响视觉信息处理这一假设。噪声水平的变化由在大脑中产生过量噪声的外部因素引入。

方法

通过暴露于450 MHz低频调制微波辐射来产生过量噪声。这种暴露已被证明会增加扩散、改变膜静息电位、门控变量和细胞内钙外流。九名健康志愿者在较低（无微波）和较高（有微波）噪声水平下通过了实验方案。向受试者依次呈现两张不熟悉的年轻男性面孔的照片（视觉刺激）。任务是随后从一组六张照片中识别出这些照片，并确定它们的呈现顺序。每个受试者在较低噪声水平下共有八次实验，在较高噪声水平下也有八次。每次实验由50次试验组成；一个受试者总共进行800次试验，在较低噪声水平下400次，在较高噪声水平下400次。采用学生t检验对结果进行统计学评估。

结果

在较低噪声水平下，以正确顺序对两种刺激的正确识别更好。所有受试对象在较低噪声水平的试验中正确答案的数量更多。在有微波暴露的n = 400次试验中，正确答案的平均数量为50.3，无暴露时为54.4，差异为7.5%，p < 0.002。在仅部分正确或错误答案的情况下，未发现较低和较高噪声水平的结果之间存在差异。