<p><b>A</b>,<b>B</b>, 1<sup>st</sup> and 2<sup>nd</sup> principal components, respectively, for the Y-neuron response data, i.e., contributions from terms with <i>n = 1</i> and <i>n = 2</i> in Eq. (3). <b>C</b>, Sum of contributions from two first principal components (and background activity) for Y neuron. <b>D</b>, Deviation between experimental results for Y neuron and PCA results in (C). Error <i>ε</i> (cf. Eq. 1) is 0.044. <b>E</b>, Fitted transient temporal function <i>F<sub>t1</sub></i>(<i>t</i>) (Eq. 11, blue dashed line) to 1<sup>st</sup> temporal PCA component (blue solid line), and fitted transient temporal function <i>F<sub>t2</sub></i>(<i>t</i>) (Eq. 12, green dashed line) to 2<sup>nd</sup> temporal PCA component (green solid line) for early part ( t<97.5 ms) of Y-neuron data. <b>F</b>, Blue dashed line: Fitted DOG spatial functions (Eq. 10) to 1<sup>st</sup> spatial PCA component of early part (t<97.5 ms) of Y-neuron data (blue solid line). Green dashed line: Corresponding DOG function fit to the 2<sup>nd</sup> spatial PCA component (green solid line). The best fit of a DOG function (red dashed line) to the 1<sup>st</sup> spatial PCA component of the <i>last</i> part of the Y-neuron data is also shown (red line). <b>G–L</b>, Same as (A)–(F) for X-neuron response data. The deviation between experimental results and PCA results (I) corresponds to an error <i>ε</i> = 0.021.</p