Brown James M
Department of Psychology, University of Georgia, Athens, GA, USA.
Prog Brain Res. 2009;176:47-63. doi: 10.1016/S0079-6123(09)17604-5.
Understanding the relationship between bottom-up and top-down processing in visual perception and attention is challenging. An important part of that challenge is studying the roles the parvocellular (P) and magnocellular (M) retino-geniculo-cortical pathways play in visual processing and attention. The P pathway provides the dominant initial input to the ventral stream which plays an important role in object processing and is assumed to be relatively more involved in object-based attention. The faster responding M pathway provides the dominant initial input to the dorsal stream which plays an important role in processing movement and spatial location information and is assumed to be relatively more involved in space-based attention. To gain insight into the relationship between M/dorsal and P/ventral activity and deploying visual attention, we used a covert cuing paradigm to manipulate attention while bottom-up and top-down perceptual stimulus variables created M/dorsal and P/ventral-biased conditions. One study examined the object advantage, where responses are faster for within-relative to equidistant between-object shifts of attention. Visual stream contributions to object- and spaced-based attention were revealed using psychophysically equiluminant conditions expected to reduce M/dorsal activity. Other studies investigating visual stream contributions to location-based inhibition of return (IOR) used IOR magnitude as an indicator of the ease or difficulty of deploying spatial attention. Greater IOR was found under P/ventral-biased conditions. Less IOR was found under M/dorsal-biased conditions. The results support the use of M/dorsal and P/ventral-biased conditions as a valuable strategy for studying the relationship between visual stream activity and shifting attention.
理解视觉感知与注意力中自下而上和自上而下加工之间的关系具有挑战性。这一挑战的一个重要部分是研究小细胞（P）和大细胞（M）视网膜 - 膝状体 - 皮质通路在视觉加工和注意力中所起的作用。P通路为腹侧流提供主要的初始输入，腹侧流在物体加工中起重要作用，并且被认为相对更多地参与基于物体的注意力。反应更快的M通路为背侧流提供主要的初始输入，背侧流在运动和空间位置信息加工中起重要作用，并且被认为相对更多地参与基于空间的注意力。为了深入了解M/背侧和P/腹侧活动与视觉注意力分配之间的关系，我们使用了一种隐蔽线索范式来操纵注意力，同时自下而上和自上而下的感知刺激变量创造了M/背侧和P/腹侧偏向的条件。一项研究考察了物体优势，即在物体内部相对于等距物体间注意力转移时反应更快。使用预期会降低M/背侧活动的心理物理学等亮度条件揭示了视觉流对基于物体和基于空间的注意力的贡献。其他研究调查视觉流对基于位置的返回抑制（IOR）的贡献，使用IOR大小作为空间注意力分配难易程度的指标。在P/腹侧偏向条件下发现更大的IOR。在M/背侧偏向条件下发现较小的IOR。结果支持使用M/背侧和P/腹侧偏向条件作为研究视觉流活动与注意力转移之间关系的一种有价值的策略。
