The Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Meibergdreef 47, 1105 BA Amsterdam, the Netherlands.
The Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Meibergdreef 47, 1105 BA Amsterdam, the Netherlands; Department of Integrative Neurophysiology, Centre for Neurogenomics and Cognitive Research, VU University, De Boelelaan 1085, 1081 HV Amsterdam, the Netherlands; Psychiatry Department, Academic Medical Center, Meibergdreef 5, 1105 AZ Amsterdam, the Netherlands.
Curr Biol. 2014 Dec 15;24(24):2869-77. doi: 10.1016/j.cub.2014.10.007. Epub 2014 Nov 20.
Object-based attention can group image elements of spatially extended objects into coherent representations, but its mechanisms have remained unclear. The mechanisms for object-based attention may include shape-selective neurons in higher visual cortical areas that feed back to lower areas to simultaneously enhance the representation of all image elements of a relevant shape. Another, nonexclusive mechanism is the spread of attention in early visual cortex according to Gestalt rules, which could successively add new elements to a growing object representation.
We investigated the dynamics of object-based attention in the primary visual cortex of monkeys trained to perform a contour-grouping task. The animals mentally traced a target curve through the visual field and ignored a distracting curve. Neuronal responses elicited by the target curve were enhanced relative to those elicited by distracting curve. Remarkably, the response enhancement was delayed for neurons with receptive fields farther from the start of the tracing process. We could therefore measure propagation speed and found that it was low if curves were nearby and that it increased if curves were far apart. The results are well explained by an "attentional growth-cone" model, which holds that the response enhancement can spread in multiple visual cortical areas with different receptive field sizes at a speed of approximately 50 ms per receptive field.
Our findings support an active role for early visual areas in object-based attention because neurons in these areas gradually spread enhanced activity over the representation of relevant objects.
基于对象的注意力可以将空间扩展对象的图像元素分组为连贯的表示，但其机制仍不清楚。基于对象的注意力机制可能包括高视觉皮层区域中的形状选择性神经元，这些神经元反馈到较低区域，以同时增强相关形状的所有图像元素的表示。另一种非排他性机制是根据格式塔规则在早期视觉皮层中扩散注意力，这可以依次将新元素添加到不断增长的对象表示中。
我们研究了在接受过轮廓分组任务训练的猴子的初级视觉皮层中基于对象的注意力的动态。动物通过视觉场跟踪目标曲线并忽略分心曲线。与引起分心曲线的反应相比，引起目标曲线的神经元反应得到增强。值得注意的是，对于远离跟踪过程起点的感受野的神经元，响应增强会延迟。因此，我们可以测量传播速度，发现如果曲线靠近，速度会很低，如果曲线远离，速度会增加。结果很好地解释了“注意力生长锥”模型，该模型认为响应增强可以以大约 50ms 每个感受野的速度在多个具有不同感受野大小的视觉皮层区域中传播。
我们的发现支持早期视觉区域在基于对象的注意力中的积极作用，因为这些区域中的神经元逐渐在相关对象的表示上扩散增强的活动。
