Parry N R, Murray I J, Hadjizenonos C
Vision Science Centre, Manchester Royal Eye Hospital, UK.
Vision Res. 1999 Oct;39(21):3491-7. doi: 10.1016/s0042-6989(99)00098-x.
The spatial tuning function of the 8 Hz reversal Visual Evoked Potential (VEP) is frequently bimodal. This amplitude 'notch' largely disappears with 16 Hz pattern onset-offset (on-off) stimulation. To investigate the effect of temporal frequency on this phenomenon, we tested seven subjects using a range of rates centred on 8 Hz (reversal) and 16 Hz (on-off). With reversal, a deep notch was present at all temporal frequencies. A much shallower notch was evident with on-off. The on-off and reversal functions differed only in their low spatial frequency branches (below 4.5 c deg-1) where, as temporal frequency decreased, the reversal response was reduced by 50%, whilst the on-off responses doubled in amplitude. Thus, although they behave differently with on-off and reversal, multiple spatial frequency mechanisms are evident with both forms of stimulation.
8赫兹反转视觉诱发电位（VEP）的空间调谐功能通常是双峰的。随着16赫兹图形开-关（on-off）刺激，这种幅度“凹陷”在很大程度上消失。为了研究时间频率对这一现象的影响，我们以8赫兹（反转）和16赫兹（on-off）为中心的一系列频率测试了7名受试者。对于反转刺激，在所有时间频率下都存在一个深凹陷。对于on-off刺激，凹陷则明显浅得多。on-off和反转功能仅在其低空间频率分支（低于4.5 c deg-1）有所不同，在该分支中，随着时间频率降低，反转反应降低50%，而on-off反应幅度加倍。因此，尽管它们在on-off和反转刺激下表现不同，但两种刺激形式都明显存在多种空间频率机制。
