Neuromagnetic responses to chromatic flicker: implications for photosensitivity
Neuromagnetic responses to chromatic flicker: implications for photosensitivity
复制标题
对色闪烁的神经磁反应：对光敏性的影响
作者：
Katsumi Watanabe;T. Imada;K. Nihei;S. Shimojo
视觉刺激引起的皮层过度兴奋常导致光敏性癫痫。在这里，我们表明，即使在正常受试者，长时间的刺激与低亮度彩色（等亮度）闪烁引起的神经磁活动的初级视觉皮层，发展缓慢（高达1000毫秒），并取决于闪烁的颜色组合。这一结果表明，色彩敏感性是皮质兴奋的一个关键因素，它可以随着时间的推移被闪烁刺激放大。我们进一步表明，瞬态活动发生在顶枕沟早在闪烁发作后100-400毫秒，这是负相关的，后来的枕活动。早期的顶枕活动可能反映了一种防御机制，抑制皮质过度活跃，由于色彩闪烁。
Excessive cortical excitation due to visual stimulation often leads to photosensitive epilepsy. Here we demonstrate that even in normal subjects, prolonged stimulation with low-luminance chromatic (equiluminant) flicker evokes neuromagnetic activity in the primary visual cortex, which develops slowly (up to 1000 ms) and depends on the color combination of flicker. This result suggests that chromatic sensitivity is a critical factor of cortical excitation, which can be amplified over time by a flickering stimulus. We further show that transient activity occurs in the parieto-occipital sulcus as early as 100–400 ms after flicker onset, which is negatively correlated with the later occipital activity. The early parieto-occipital activity may reflect a defensive mechanism that suppresses cortical hyperactivity due to chromatic flicker.