Thompson K G, Schall J D
Department of Psychology, Vanderbilt Vision Research Center, Vanderbilt University, 301 Wilson Hall, Nashville, TN 37240, USA.
Vision Res. 2000;40(10-12):1523-38. doi: 10.1016/s0042-6989(99)00250-3.
We have investigated the neural basis of visual detection in monkeys trained to report the presence or absence of a visual stimulus that was rendered intermittently detectable by backward masking. Neurons were recorded in the frontal eye field (FEF), an area located in prefrontal cortex that is involved in converting the outcome of visual processing into a command to shift gaze. The behavioral and neuronal data were analyzed in terms of signal detection theory. We found that the initial visual responses in FEF provided signals that could form the basis for correct or erroneous detection of the target. A later phase of prolonged elevated activity occurred in many visual neurons and all movement neurons that was highly correlated with the monkey's report of target presence. When observed in movement cells that project to oculomotor structures, this period of activation is interpreted as a motor command leading to the behavioral response. When observed in visual cells that do not project to oculomotor structures, the later period of activation does not admit to the motor command interpretation. Because the visual neurons likely contribute to the feedback pathway to visual cortical areas, we hypothesize that the later selective activation in the prefrontal visual neurons interacts with ongoing activity in visual cortical areas contributing to the process by which a particular sensory representation receives enhanced activation and thereby engages attention and awareness.
我们研究了经过训练的猴子进行视觉检测的神经基础，这些猴子被训练报告通过逆向掩蔽使其间歇性可检测的视觉刺激的有无。在额叶眼区（FEF）记录神经元活动，额叶眼区位于前额叶皮层，参与将视觉处理的结果转化为转移视线的指令。根据信号检测理论对行为和神经元数据进行了分析。我们发现，额叶眼区最初的视觉反应提供了可以作为正确或错误检测目标基础的信号。许多视觉神经元和所有运动神经元随后出现了持续升高的活动阶段，这与猴子对目标存在的报告高度相关。当在投射到动眼神经结构的运动细胞中观察到这种情况时，这段激活期被解释为导致行为反应的运动指令。当在不投射到动眼神经结构的视觉细胞中观察到时，后期的激活期不被认为是运动指令的解释。由于视觉神经元可能有助于通向视觉皮层区域的反馈通路，我们假设前额叶视觉神经元后期的选择性激活与视觉皮层区域的持续活动相互作用，有助于特定感觉表征获得增强激活从而引起注意和意识的过程。
