FUNCTIONAL ORGANIZATION OF THE VENTRAL STREAM IN NORMALLY DEVELOPING CHILDREN AN

正常发育儿童腹侧流的功能组织

• 批准号: 7378984
• 负责人: BARBARA LANDAU
• 金额: $ 0.18万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-12-01 至 2006-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7378984
• 关键词: FUNCTIONAL; ORGANIZATION; VENTRAL; STREAM; NORMALLY

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The present studies examine whether the visual object category-dependent activity found maong adults in ventral stream areas, including posterior temporal and ventrolateral occipital cortices, exists during development and whether this organization is disrupted by a developmental disorder. The disorder examined is Williams Syndrome (WS), a rare genetic deficit characterized by an uneven cognitive profile. People with WS have intact face recognition capacities in spite of severe impairments on visual spatial tasks such as block construction. This pattern of visual abilities has led to the proposal that the genetic defect in WS does not alter the visual representations underlying object recognition in the ventral stream but does cause extensive damage to the visual spatial representations subserved by the dorsal stream. The purpose of these studies is to evaluate this claim by examining in detail ventral stream function in WS. We will compare the pattern of fMRI activation in adolescents and young adults with WS to normally developing populations. Two normally developing control groups will be used, children matched approximately on chronological age (CA matches: ages 14-18) and children matched in mental age (MA matches: ages 6-9). Currently, little evidence exists on the development of the ventral stream, so we will first examine whether children display similar ventral stream organization to that found previously in adults, and then whether people with WS resemble either CA or MA matches. This evidence will address an ongoing debate on whether genetic deficits with severe consequences lead to novel strategies and neural reorganization over development (Karmiloff-Smith, 1998). To examine this, two functional MRI experiments are proposed. One task will use passive viewing of human faces, houses, cats, and shoes to test ventral stream function. The second task will use a working memory paradigm with the same objects. By utilizing a variety of object kinds as stimuli, we can investigate whether the spared face recognition abilities found in WS indicate a fully functioning ventral stream, a small area of preserved function I the Fusiform Face Area (FFA), or an alternative system. Passive viewing provides a task with low task demands, thus minimizing confounds related to task difficulty. The well established memory paradigm also has distinct benefits; in addition to producing robust ventral stream activity, it enables us to examine prefrontal activation and assess the relationship between activation and performance on the working memory task. In behavioral studies, people with WS display memory impairments with some object categories, a deficit that may reflect abnormal activation in prefrontal areas. These imaging studies, together with the extensive behavioral studies done in our laboratory, will provide crucial, detailed information on the visual functions subserved by the ventral stream and prefrontal cortex in people with WS and normally developing children.

该子项目是利用 NIH/NCRR 资助的中心拨款提供的资源的众多研究子项目之一。子项目和研究者 (PI) 可能已从另一个 NIH 来源获得主要资金，因此可以在其他 CRISP 条目中得到体现。列出的机构是中心的机构，不一定是研究者的机构。目前的研究探讨了在发育过程中，在腹侧流区域（包括后颞叶和腹外侧枕叶皮质）中发现的Maong成虫的视觉对象类别依赖性活动是否存在，以及该组织是否受到发育障碍的破坏。所检查的疾病是威廉姆斯综合症（WS），这是一种罕见的遗传缺陷，其特征是认知特征不均匀。尽管在视觉空间任务（例如块构建）方面存在严重障碍，但患有 WS 的人仍具有完整的面部识别能力。这种视觉能力模式导致了这样的建议：WS 的遗传缺陷不会改变腹侧流中物体识别的视觉表征，但确实会对背侧流所支持的视觉空间表征造成广泛损害。这些研究的目的是通过详细检查 WS 的腹侧流功能来评估这一说法。我们将患有 WS 的青少年和年轻人与正常发育人群的 fMRI 激活模式进行比较。将使用两个正常发育的对照组，即按实际年龄大致匹配的儿童（CA 匹配：14-18 岁）和心理年龄匹配的儿童（MA 匹配：6-9 岁）。目前，关于腹侧流发育的证据很少，因此我们将首先检查儿童是否表现出与以前在成人中发现的相似的腹侧流组织，然后检查 WS 患者是否与 CA 或 MA 匹配。这一证据将解决关于具有严重后果的遗传缺陷是否会导致发育过程中的新策略和神经重组的持续争论（Karmiloff-Smith，1998）。为了检验这一点，提出了两个功能性 MRI 实验。其中一项任务将使用被动观察人脸、房屋、猫和鞋子来测试腹侧流功能。第二个任务将使用具有相同对象的工作记忆范例。通过利用各种物体类型作为刺激，我们可以研究 WS 中发现的保留的面部识别能力是否表明功能齐全的腹侧流、保留功能的小区域（梭状面部区域（FFA））或替代系统。被动观看提供了任务要求较低的任务，从而最大限度地减少了与任务难度相关的混乱。完善的记忆范式也有明显的好处；除了产生强大的腹侧流活动之外，它还使我们能够检查前额叶激活并评估激活与工作记忆任务表现之间的关系。在行为研究中，WS 患者对某些物体类别表现出记忆障碍，这种缺陷可能反映了前额叶区域的异常激活。这些成像研究，加上我们实验室进行的广泛的行为研究，将提供关于 WS 患者和正常发育儿童的腹侧流和前额叶皮层所支持的视觉功能的重要而详细的信息。