Uncovering the nature of object representations in the human dorsal visual cortex

人类的视觉系统使我们能够识别物体（例如，这是一个杯子），并以惊人的轻松和准确的方式对它们采取行动（例如，抓住杯子）。几十年来，人们普遍认为这些不同的功能依赖于分离的皮层通路。特别是，腹侧通路支持物体识别，而背侧通路支持视觉引导动作。然而，最近的证据挑战了这种二元区分，并表明背侧“动作”通路的区域也产生了在物体感知中起作用的形状表征。******尽管最近取得了进展，但由背侧通路衍生的形状表征的性质仍然不清楚。阐明这些表征的一个主要挑战是它们受到多种因素的调节，例如(a)来自其他大脑区域的输入，(b)任务需求和(c)刺激的物理特征。因此，本研究计划的首要目标是通过考虑不同因素调节这些表征的程度来阐明背部形状表征的本质。在两个互补的项目中，我们将利用各种最先进的行为和神经成像技术来解决这些问题。*第一个项目将检查独立的形状表征是否由背侧通路计算，即使来自腹侧通路的输入被最小化。为此，我们将利用明确设计的实验技术，将形状处理偏向于背侧通路。主要的预测是，尽管两个通路之间存在相互联系，但背侧通路派生出独立的形状表征。******第二个项目将探索任务需求调节背部形状表征的程度。为此，需要处理不同形状属性的各种任务将被采用，而视觉输入将保持不变。我们预测，尽管背侧通路对形状信息具有自动敏感性，但背侧表征将受到任务需求的调节，特别是涉及空间处理的任务。******总之，这个研究项目有可能阐明形状感知的神经基础，这是一种基本的感知能力。此外，这些见解可能会揭示先天性和后天障碍的潜在机制，其中视觉感知受损。

The human visual system enables us to recognize objects (e.g., this is a cup) and act upon them (e.g., grasp the cup) with astonishing ease and accuracy. For decades, it was widely accepted that these different functions rely on separated cortical pathways. In particular, the ventral pathway subserves object recognition, while the dorsal pathway subserves visually guided actions. However, recent evidence challenges this binary distinction and suggests that regions in the dorsal “action” pathway also derive shape representations that play a role in object perception. ******Despite this recent progress, the nature of shape representations derived by the dorsal pathway is still unclear. One major challenge in elucidating these representations is that they are modulated by a variety of factors, such as (a) the inputs from other brain regions, (b) task demands and (c) the physical features of the stimulus. Thus, the overarching goal of this research program is to shed light on the nature of dorsal shape representations by contemplating the extent to which different factors modulate these representations. In two complementary projects, we will address these questions, by utilizing a variety of state-of-the-art behavioural and neuroimaging techniques.*The first project will examine whether independent shape representations are computed by the dorsal pathway, even when inputs from the ventral pathway are minimized. To this end, we will utilize experimental techniques which are designed explicitly to bias shape processing to the dorsal pathway. The main prediction is that despite the interconnections between the two pathways, the dorsal pathway derives independent shape representations.******The second project will probe the degree to which task demands modulate dorsal shape representations. To that purpose, a variety of tasks, which require the processing of different shape attributes, will be employed, while the visual input will be kept constant. We predict that despite an automatic sensitivity of the dorsal pathway to shape information, dorsal representations will be modulated by task demands, particularly for tasks that involve spatial processing. ******Together, this research program has the potential to elucidate the neural underpinnings of shape perception, a fundamental perceptual ability. Moreover, these insights might shed light on the underlying mechanisms of congenital and acquired disorders in which visual perception is impaired.