Rapcsak S Z, Watson R T, Heilman K M
Department of Neurology, College of Medicine, University of Florida, Gainesville 32610.
J Neurol Neurosurg Psychiatry. 1987 Sep;50(9):1117-24. doi: 10.1136/jnnp.50.9.1117.
Visual extinction was studied in a patient with neglect from a right hemispheric lesion. Extinction occurred during double simultaneous stimulation within the same visual hemi-field (VHF). This finding suggests that interhemispheric rivalry is not a critical factor. During double simultaneous stimulation within the same VHF as well as with stimuli in different VHFs, the severity of extinction was determined by both the retinotopic and the hemi-spatial position of the extinguished stimulus. The location of the other stimulus, however, did not seem relevant. It is proposed that damage to a corticolimbic-reticular system reduces attentional capacity and that extinction during double simultaneous stimulation in the visual modality reflects an inability to distribute the limited attentional resources equally to two different locations. The severity of extinction is a measure of an unequal distribution of attention along a gradient within visual space.
对一名因右侧半球损伤而出现忽视症状的患者进行了视觉消退研究。在同一视觉半视野（VHF）内的双侧同时刺激期间出现了消退现象。这一发现表明半球间竞争不是一个关键因素。在同一VHF内的双侧同时刺激以及不同VHF内的刺激过程中，消退的严重程度由被消退刺激的视网膜定位和半空间位置决定。然而，另一个刺激的位置似乎无关紧要。有人提出，皮质边缘 - 网状系统的损伤会降低注意力容量，并且视觉模态下双侧同时刺激期间的消退反映了无法将有限的注意力资源平均分配到两个不同位置的能力。消退的严重程度是视觉空间内沿梯度注意力分配不均的一种度量。
