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

揭示人类背侧视觉皮层中物体表征的本质

• 批准号: RGPIN-2019-06677
• 负责人: Freud, Erez
• 金额: $ 2.4万
• 依托单位: York University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=739045
• 关键词: Uncovering; nature; object; representations; human

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.

人类视觉系统使我们能够识别物体（例如，这是一个杯子）并作用于它们（例如，以惊人的轻松和准确抓住杯子）。几十年来，人们普遍认为这些不同的功能依赖于独立的皮质通路。特别是，腹侧通路有助于物体识别，而背侧通路有助于视觉引导动作。然而，最近的证据挑战了这种二元的区别，并建议在背侧的“行动”通路的区域也得到形状的表征，在对象感知中发挥作用。 尽管最近的进展，形状表征的性质来自背侧通路仍然不清楚。阐明这些表征的一个主要挑战是，它们受到各种因素的调制，例如（a）来自其他大脑区域的输入，（B）任务要求和（c）刺激的物理特征。因此，本研究计划的总体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性质。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。第一个项目将研究是否独立的形状表征计算的背侧通路，即使从腹侧通路的输入最小化。为此，我们将利用明确设计的实验技术，以偏置背侧通路的形状处理。主要的预测是，尽管这两个路径之间的互连，背侧路径派生独立的形状表示。第二个项目将探讨任务需求调节背形状表征的程度。为此，将采用各种任务，这些任务需要处理不同的形状属性，而视觉输入将保持不变。我们预测，尽管背侧通路的形状信息的自动敏感性，背侧表示将调制的任务需求，特别是涉及空间处理的任务。 总之，这项研究计划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，这些见解可能揭示了先天性和后天性疾病的潜在机制，其中视觉感知受损。