The development of perceptual spatial interactions: psychophysics and neurophysiology

长期以来，视觉发育的研究一直被两个假说所指导：视觉发育在婴儿期完成，不同的视觉功能(如对比敏感度、敏锐度、运动知觉、形状知觉)以相同的速度成熟。这就解释了为什么在婴儿期以后很少有关于视觉发展的研究。我们实验室最近的一系列研究对这两个假设提出了严重的质疑。事实上，我们发现，一些视觉功能在儿童后期甚至青春期早期还没有达到成熟，而且并不是所有的视觉功能都以同样的速度成熟。 为了更好地理解这种长期成熟的机制，拟议的研究将调查知觉横向相互作用的功能结构的发展。当视觉目标的感知因邻近元素的存在而改变时，就会发生空间横向相互作用。了解侧向相互作用发展的基础规则可以提供有关视觉系统组成的关键信息。具体地说，我们利用心理物理学和神经生理学(视觉诱发电位)的方法，致力于研究侧向空间相互作用的发展，以了解1)视神经元的抑制反应，2)它们的方位和空间频率调节，以及3)它们的对比度增益控制的规律。 这一研究对我们理解人脑发育及其功能组织和可塑性具有重要意义。这将引起神经科学、生物学、工程学和医学领域的研究人员的极大兴趣。这项研究将使加拿大研究人员在发展神经科学领域获得国际领先地位。

Research on visual development has long been guided by two hypotheses: visual development is complete during infancy and the different visual functions (e.g., contrast sensitivity, acuity, motion perception, form perception) mature at the same rate. This explains why there are few studies of visual development beyond infancy. A series of recent studies from our laboratory cast serious doubt about these two hypotheses. Indeed, we found that several visual functions do not attain maturity before late childhood or even early adolescence and that not all visual functions mature at the same rate. In an attempt to better understand the mechanisms of this protracted maturation, the proposed research will investigate the development of the functional architecture of perceptual lateral interactions. Spatial lateral interactions occur when the perception of a visual target is altered by the presence of neighbouring elements. Understanding the rules that underlie the development of lateral interactions provides critical information about the make-up of the visual system. Specifically, by means of psychophysical and neurophysiological (Visual Evoked Potentials) methodologies, we endeavour to study the development of lateral spatial interactions in order to understand the rules of 1) the suppressive responses of visual neurons, 2) their orientation and spatial frequency tuning, and 3) their contrast gain control. The research supported by the current proposal is important for our understanding of human brain development and its functional organization and plasticity. This will be of great interest for researchers in the field of neurosciences, biology, engineering, and medicine. This research will enable Canadian researchers to gain international leadership in the field of developmental neurosciences.