Neural substrates of attention and orienting

描述（由申请人提供）：视觉定向可以通过认知控制自愿产生，也可以通过刺激驱动的过程从外部（反射性）诱发。此外，定向可能是隐蔽的（注意力转移）或明显的（眼球运动）。我们提出了一个紧张性抑制模型的注意力和定向，详细说明了这些过程及其相互作用的特定神经基板。鉴于帕金森病（PD）中基底神经节和额叶的已知破坏，该人群代表了模型的理想测试。因此，这项建议将对PD中的定向进行系统的调查，并将是第一项全面检查这两个维度（即，自愿与自反和隐蔽与公开）。在第一部分中，我们将比较PD和对照组的自愿和反射性外显定向。基于我们和其他人的先前研究，我们预期PD受试者在自主眼动方面存在缺陷，但在某些条件下，在反射性眼动方面更有效率。在第二部分中，我们将研究工作记忆不足与未能抑制无关信息的相对重要性，以解释PD中自愿表现不佳，这两个因素经常被认为是自愿任务表现不佳的可能解释。第三部分的建议将比较自愿和反射性注意在PD和控制科目。没有以前的研究在PD检查反射性空间注意独立的自愿空间注意。最后一部分的建议将研究不同的感觉运动转换的视觉空间注意在PD的效果。我们以前发现，简单或直接的刺激-反应（S-R）映射显示了不同的注意时间过程比更复杂，间接的S-R映射。PD患者在某些视觉转换方面存在困难。因此，我们将检查和比较的影响，S-R映射的注意范式在PD和控制的主题。所有拟议的实验将系统地操纵PD受试者的药物状态，以阐明药物在减轻PD定向功能障碍中的作用。尽管其明显的重要性，我们不知道任何公开或隐蔽的定向研究，已经审查了这个问题。最后，这个建议的结果将有重要的影响，我们的理解和模型之间的关系，注意和外显定向。

DESCRIPTION (provided by applicant): Visual orienting can be either generated voluntarily via cognitive control or evoked externally (reflexively) via stimulus-driven processes. In addition, orienting may be either covert (attentional shifts) or overt (eye movements). We have proposed a tonic inhibition model of attention and orienting that details specific neural substrates for these processes and their interactions. Given the known disruption of the basal ganglia and frontal lobes in Parkinson's disease (PD), this population represents an ideal test of the model. This proposal will thus carry out a systematic investigation of orienting in PD, and will be the first study to comprehensively examine performance across both of these dimensions (i.e., voluntary vs. reflexive and covert vs. overt) in this population. In the first section we will compare voluntary and reflexive overt orienting in PD and control subjects. Based on our and others' previous research, we expect PD subjects to be deficient in voluntary eye movements but, under certain conditions, to be more efficient in reflexive eye movements. In a second section, we will examine the relative importance of deficient working memory vs. failure to inhibit irrelevant information in explaining poor voluntary performance in PD, both factors having been often proposed as possible explanations for poor performance on voluntary tasks. A third section of the proposal will compare voluntary and reflexive attention in PD and control subjects. No previous study in PD has examined reflexive spatial attention independent of voluntary spatial attention. The final section of the proposal will study the effect of different sensorimotor transformations on visuospatial attention in PD. We have previously found that simple or direct stimulus-response (S-R) mappings show a different attentional time course than do more complex, indirect S-R mappings. PD patients have difficulties with some visuomotor transformations. Hence, we will examine and compare the effects of S-R mappings on attentional paradigms in PD and control subjects. All proposed experiments would systematically manipulate medication status of the PD subjects to clarify the role of medication in alleviating orienting dysfunctions in PD. Despite its obvious importance, we are unaware of any overt or covert orienting studies that have examined this issue. Finally, the results of this proposal will have important implications for our understanding and modeling of the relation between attention and overt orienting.