视觉搜索左右视野靶时脑两半球加工特点

Hemishere Process Progression when Vision Searching the Target in Left and Right Vision Field

研究视觉分别搜索在左右视野靶时,脑两侧前额叶视觉加工的机制。14名有偿被试参加实验。实验任务是从正圆中所存在的垂直方向的箭头,搜索出水平方向箭头,并判断箭头方向。靶所在左右视野经过镜面处理完全对应。结果发现当靶出现约220ms后左右两侧脑区ERP出现分叉点,靶对侧与靶同侧的前脑区相比有非常显著的负向电位活动,对侧和同侧的N2延续40-80ms。分析认为靶对侧前额脑区N2负向活动增强是注意的等级提高,聚焦点收窄,使所要加工的靶在主效应脑区(靶视野对侧脑区)“跃显”出来,在得到正反馈诱导的同时,也得到更多的资源,靶同侧脑区N2可能与中断或阻止其他无关信息的涌入有关。

In the present study, we measured event-related potentials （ERPs） evoked by vision searching the target respectively in the left and right vision fields for hemishere process progression. 14 paid subjeets took part in tasks of searching ＂←＂ or ＂→＂ among ＂ ↑↓ ＂ in the rotundity array and distinguishing the arrow direction ＂←＂ or ＂→＂ among ＂ ↑↓ ＂. The target arrows were equal and corresponding in directions and positions after being treated enantiomorphously. We found after probe presentations in the latency range of 150- 260 reset, the homologous and holomorphie prefrontal＇ amplitudes were bifurcate, and N2 sustained 40-80 ms. All subjects showed elevated negative amplitudes in the target field of vision holomorphic prefrontal. These findings supported the assumption of advanced attention level and zoomed the attention focus, so that the target stood out for processing post in the primary effect prefrontal （the target vision fields of holomorphic prefrontal ）, and for gaining more cognitive processing resources. Nevertheless, the N2 elevated positive amplitudes in the homologous prefrontal were relative with the breakdown or prevented the useless information from getting into the homologous profrontal.