Human oscillatory potentials: intensity-dependence of timing and amplitude
Human oscillatory potentials: intensity-dependence of timing and amplitude
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DOI：
10.1007/s10633-008-9125-x
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发表时间：
2008-11-01
影响因子：
1.4
通讯作者：
Kraft, Timothy W.
中科院分区：
文献类型：
--
作者：
Hancock, Heather A.;Kraft, Timothy W.
振荡电位（Oscillatory potentials，OP）在糖尿病视网膜病变、青光眼和血管闭塞中被描述为振幅降低或延迟。虽然OP被认为具有有用的诊断应用，但它们的一些基本生理特性仍有待充分描述。在本研究中，我们研究了OPs的时间和幅度与刺激强度之间的关系。五名正常志愿者的一只眼睛被麻醉并扩张。暗适应全视野ERG记录为0.0125-40 cd s/m（2）的白色刺激。OP的定时测量为刺激后15 ms开始的四个峰的峰值时间（TTP）之和。振幅取为这些相同峰的振幅之和。作为替代值，OP强度由OP曲线下的面积或频域中150 Hz（+/- 30 Hz）附近的功率表示。的OP时间，如TTP测量，被发现是负相关的刺激强度。OP振幅随强度增加而增加，但当刺激强度超过约4 cd s/m（2）时则下降。在明亮的光强度，TTP继续缩短，但幅度，功率和面积都下降。个体OP表现相似，反映了整个群体的总体反应模式。更明亮的刺激产生更大，更快的OP的刺激强度高达用于产生OP的强度标准（3.5 cd s/m（2））。我们已经将刺激的范围扩展到比ISCEV标准高10倍的范围，以产生OP，并发现时间继续加速，但OP幅度，OP面积和OP功率在更高的刺激强度下都下降。OP能量的这些替代措施很容易测量，并可能有助于进一步的研究。
Oscillatory potentials (OPs) have been described as reduced in amplitude or delayed in diabetic retinopathy, glaucoma, and vascular occlusions. Although OPs are thought to have useful diagnostic applications, some of their basic physiologic properties remain to be fully described. In the present study, we examined the relationship between the timing and amplitude of OPs and stimulus intensity. Five normal volunteers had one eye anesthetized and dilated. Dark-adapted full-field ERGs were recorded to white stimuli of 0.0125-40 cd s/m(2). The timing of the OPs was measured as the sum of the time to the peak (TTP) of four peaks beginning at 15 ms after the stimulus. The amplitude was taken as the sum of the amplitudes of those same peaks. As an alternative value, OP strength was represented by the area under the OP curve or power around 150 Hz (+/- 30 Hz) in the frequency domain. The OP timing, as measured by TTP, was found to be inversely related to stimulus intensity. OP-amplitudes grew with intensity, but then declined for stimulus intensities above about 4 cd s/m(2). At bright light intensities, the TTP continued to shorten, yet amplitudes, power, and area all declined. Individual OPs behaved similarly and reflected the overall response pattern of the group as a whole. Brighter stimuli produced larger, faster OPs for stimulus strengths up to the intensity standard used to produce OPs (3.5 cd s/m(2)). We have extended the range of stimuli to some 10-fold higher than the ISCEV standard for producing OPs and found that the timing continued to accelerate but that OP-amplitudes, OP-area, and OP-power all decline at higher stimulus intensities. These alternative measures of OP energy are easily measured and may be useful for further studies.