Brain Mechanisms Underlying Human Motion Perception

看到运动中的物体的能力是所有物种视觉的一个基本方面。我研究的总体目标是了解人类大脑通常如何感知运动。一个人完全缺乏感知运动的能力是很罕见的，但某些发育障碍会影响感知特定类型运动的能力。此外，不同类型的运动对儿童运动知觉的发展也不同。我们研究典型和非典型的视觉发育，以阐明运动知觉的正常机制。人们通常会用大脑中潜在的通路或流来解释我们的研究类型。形状和颜色感知通常与腹侧流有关，运动感知与背侧流有关。有人认为，在儿童时期，背侧流比腹侧流更容易受到损伤。然而，视觉处理的背侧/腹侧观点可能过于简单，最近的证据表明，腹侧流在低速运动感知中起作用。这就对背流脆弱性理论的有效性提出了质疑。本提案的具体目标是通过使用两种非侵入性技术识别涉及处理快动作和慢动作的大脑区域来解决这一争议。通过一种叫做心理物理学的行为技术，电脑“游戏”将被用来测量儿童感知不同类型运动的能力。通过功能性磁共振成像（MRI），当儿童观看不同类型的运动时，大脑活动的变化区域将被确定。我们的方法是独特的，将儿童（3至17岁）运动知觉的典型成熟信息与由弱视、阅读障碍或早产引起的运动知觉变化信息相结合，并将这些人群的心理物理和功能MRI数据联系起来。这项工作将对现有的运动感知模型提出新的挑战，并有助于解决当前的一些争议。这将对加拿大儿童和成人因神经紊乱或脑损伤引起的视力问题的治疗和康复具有实际意义。

The ability to see objects in motion is a fundamental aspect of vision in all species. The overall goal of my research is to understand how the perception of motion is normally achieved by the human brain. It is rare for a person to totally lack the ability to perceive motion, but certain developmental disorders affect the ability to perceive specific types of motion. In addition, the development of motion perception in children differs for different types of motion. We study typical and atypical visual development to clarify normal mechanisms of motion perception. It is common to interpret our type of research in terms of the underlying pathways or streams in the brain. Form and colour perception are typically linked to the ventral stream and motion perception to the dorsal stream. It has been suggested that the dorsal stream is more vulnerable to damage during childhood than the ventral stream. However, the dorsal/ventral view of visual processing is probably too simplistic, and more recent evidence implicates the ventral stream in motion perception for slow speeds. This brings into question the usefulness of the dorsal stream vulnerability idea. The specific goal of this proposal is to address this controversy by identify the brain regions involved in the processing of fast and slow motion using two non-invasive techniques. With a behavioural technique called psychophysics, computer "games" will be used to measure a child's ability to perceive different types of motion. With functional magnetic resonance imaging (MRI), regions where brain activity changes while a child watches different types of motion will be determined. Our approach is unique in combining information about the typical maturation of motion perception in children (3 to 17 years old) with information about the changes in motion perception caused by lazy eye, dyslexia or preterm birth, and in the linking of psychophysical and functional MRI data in these populations. This work will provide new challenges for existing models of motion perception and help resolve some current controversies. There will be practical implications for the treatment and rehabilitation of Canadian children and adults with visual problems caused by neural disorders or brain injury.