A COMPUTATIONAL MODEL OF THE AMPLITUDE AND IMPLICIT TIME OF THE B-WAVE OF THE HUMAN ERG
A COMPUTATIONAL MODEL OF THE AMPLITUDE AND IMPLICIT TIME OF THE B-WAVE OF THE HUMAN ERG
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DOI：
10.1017/s0952523800009275
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发表时间：
1992-02-01
影响因子：
1.9
通讯作者：
BIRCH, DG
中科院分区：
文献类型：
--
作者：
HOOD, DC;BIRCH, DG
为了提高ERG在识别适应、发育和疾病过程的位点和机制中的有用性，评估了基于Granit ERG分析的理论框架。该框架假设ERG是两种电位的总和，一种是由受体产生的P3，另一种是由INL细胞产生的P2。Hood和Birch（1990 a，B）证明，a波的前沿可以通过用于描述单视杆细胞感受器响应的模型定量描述。该模型提供了P3（t），对于任何给定的闪光强度，作为时间的函数的理论受体响应。在此框架下分析了正常观察者和视网膜疾病患者的ERG，首先通过计算机减去预测的P3（t）响应来推导P2。这一分析是成功的，然后推导出ERG的计算模型。P2（t）的模型由线性滤波器和静态非线性滤波器构成，并使用P3（t）作为输入。对于任何给定的闪光强度，ERG则为P3（t）+P2（t）。该模型描述了（1）正常暗适应观察者的隐式时间和谷峰b波振幅随闪光强度的变化;以及（2）三名视网膜疾病患者的b波隐式时间和振幅的变化。（1）必须非常小心地解释Naka-Rushton方程对谷峰b波振幅的拟合。(2)当INL受到视网膜疾病的影响时，b波可能是INL活性的非常差的反映。(3)b波的隐式时间可以提供受体敏感性的量度。
To improve the usefulness of the ERG in identifying the sites and mechanisms of adaptation, development, and disease processes, a theoretical framework based upon Granit's analysis of the ERG was evaluated. The framework assumes that the ERG is the sum of two potentials, one, P3, generated by the receptors and the other, P2, generated by the cells of the INL. Hood and Birch (1990a,b) demonstrated that the leading edge of the a-wave can be quantitatively described by a model used to describe the response from single rod receptors. This model provides P3(t), a theoretical receptor response as a function of time, for any given flash intensity. The ERGs from normal observers and patients with retinal diseases were analyzed in this framework, first by deriving P2 by computer subtracting the predicted P3(t) responses. This analysis was successful and a computational model of the ERG was then derived. The model of P2(t) was constructed with linear filters and a static nonlinearity and using P3 (t) as the input. The ERG for any given flash intensity is then P3(t) + P2(t). The model describes (1) the change both in implicit times and in trough-to-peak b-wave amplitudes with flash intensity for the normal, dark-adapted observers; and (2) the changes in b-wave implicit times and amplitudes for three patients with retinal diseases.Among the implications drawn from these analyses were as follows: (1) The fits of the Naka-Rushton equation to trough-to-peak b-wave amplitudes must be interpreted with great care. (2) When the INL is affected by retinal disease, the b-wave may be a very poor reflection of INL activity. (3) The implicit time of the b-wave can provide a measure of receptor sensitivity.