Adaptation and multivoxel codes in high-level visual cortex

高级视觉皮层的适应和多体素编码

• 批准号: 8510186
• 负责人: RUSSELL A EPSTEIN
• 金额: $ 20万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-04-01 至 2015-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8510186
• 关键词: Address; Amblyopia; Anterior; Area; Brain region; Categories; Cereals; Code; Complex; Data Set; Disease; Episodic memory; Fruit; Functional Magnetic Resonance Imaging; Goals; Health; Imaging Techniques; Individual; Investigation; Knowledge; Lateral; Linguistics; Measures; Methods; Neurons; Oysters; Pattern; Process; Recovery; Shapes; Signal Transduction; Specificity; Stimulus; Synapses; Techniques; Testing; Time; Ursidae Family; Vision; Visual; Visual Cortex; Visual system structure; Work; analytical tool; base; blind; cognitive neuroscience; expectation; indexing; information processing; neuromechanism; operation; public health relevance; relating to nervous system; research study; response

DESCRIPTION (provided by applicant): A core concern of cognitive neuroscience is understanding the representational distinctions made by different brain regions. Two techniques are commonly used in functional magnetic resonance imaging (fMRI) studies to investigate this issue: multivoxel pattern analysis (MVPA) and fMRI adaptation (fMRIa). Whereas MVPA examines the voxelwise response patterns elicited by different stimuli to determine which items elicit patterns that are distinguishable, fMRIa examines the effect of repeating items over time under the hypothesis that repetition of representationally-similar items will elicit a reduced response. Although MVPA and fMRIa have become part of the central toolkit of cognitive neuroscience, little is known for certain about the neuronal mechanisms that underlie these two techniques. Consequently, it has been difficult to relate results obtained through MVPA to results obtained through fMRIa. Indeed, previous work from our lab has shown that apparently inconsistent results can be obtained from fMRIa and MVPA, even when these techniques are applied to the same dataset. The main goal of the current project is to test several hypotheses about the different neuronal mechanisms that might underlie MVPA and fMRIa. Specifically, we will test whether fMRIa indexes neuronal or subneuronal tuning (Exp. 1), stimulus similarity or perceptual expectations (Exp. 2), and we will test the spatial scale of functional organization indexed by MVPA (Exp. 3). The focus of this preliminary project will be on fMRI signals in the parahippocampal place area (PPA) during viewing of real-world visual scenes and in the lateral occipital complex (LOC) during the viewing of objects. Although the current experiments do not directly examine recovery or disease, they will, if successful, provide important analytical tools for such investigations. For example, attempts to use MVPA and fMRIa to understand plasticity and cortical reorganization in amblyopia, or after recovery of sight in the blind, can only bear fruit if the interpretation of the findings in terms of underlying neural mechanisms is fully understood.

描述（由申请人提供）：认知神经科学的核心关注点是理解不同大脑区域的表征差异。功能磁共振成像 (fMRI) 研究中常用两种技术来研究这个问题：多体素模式分析 (MVPA) 和功能磁共振成像适应 (fMRIa)。 MVPA 检查不同刺激引起的体素反应模式，以确定哪些项目引起可区分的模式，而 fMRIa 则根据重复代表性相似项目会引起反应减弱的假设，检查重复项目随时间的影响。尽管 MVPA 和 fMRIa 已成为认知神经科学核心工具包的一部分，但人们对这两种技术背后的神经机制知之甚少。因此，很难将通过 MVPA 获得的结果与通过 fMRIa 获得的结果联系起来。事实上，我们实验室之前的工作表明，即使将这些技术应用于同一数据集，fMRIa 和 MVPA 也可以获得明显不一致的结果。当前项目的主要目标是测试关于可能构成 MVPA 和 fMRIa 基础的不同神经元机制的几种假设。具体来说，我们将测试 fMRIa 是否索引神经元或亚神经元调谐（实验 1）、刺激相似性或感知期望（实验 2），并且我们将测试由 MVPA 索引的功能组织的空间尺度（实验 3）。该初步项目的重点将是在观看真实世界视觉场景期间海马旁区域（PPA）和观看物体期间枕叶复合体（LOC）中的功能磁共振成像信号。尽管目前的实验不直接检查恢复或疾病，但如果成功，将为此类研究提供重要的分析工具。例如，尝试使用 MVPA 和 fMRIa 来了解弱视的可塑性和皮质重组，或者盲人视力恢复后，只有在充分理解潜在神经机制方面的发现解释的情况下才能取得成果。