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发产生，也可以通过刺激驱动的外部(反射性)过程产生。此外，定向可以是隐蔽的(注意力转移)，也可以是公开的(眼球运动)。我们提出了一个注意和定向的紧张性抑制模型，该模型详细描述了这些过程及其相互作用的特定神经底物。考虑到帕金森氏病(PD)中已知的基底节和额叶的破坏，这一群体代表了对该模型的理想测试。因此，本研究将对帕金森病的定向进行系统的研究，并将是第一个全面考察这两个维度(即自愿与反身性以及隐性与显性)在这一人群中的表现的研究。在第一节中，我们将比较帕金森病患者和对照受试者的自愿性和反身性显性定向。基于我们和其他人之前的研究，我们预计帕金森病患者在自主性眼球运动方面存在缺陷，但在某些条件下，在反射性眼球运动方面更有效率。在第二部分中，我们将检验工作记忆不足和未能抑制无关信息在解释帕金森病志愿者表现不佳方面的相对重要性，这两个因素经常被认为是志愿任务表现不佳的可能解释。提案的第三部分将比较帕金森病患者和对照受试者的自愿性注意力和反身性注意力。在帕金森病之前的研究中，没有一项研究是独立于自愿空间注意的反身性空间注意的。该提案的最后部分将研究不同感觉运动转换对帕金森病患者视觉空间注意的影响。我们之前已经发现，简单或直接的刺激-反应(S-R)映射与更复杂的间接S-R映射显示出不同的注意时间进程。帕金森病患者在某些视觉运动转换方面存在困难。因此，我们将考察和比较S-R映射对帕金森病和对照组被试注意范式的影响。所有拟议的实验都将系统地操纵PD受试者的药物状态，以阐明药物在缓解PD定向功能障碍方面的作用。尽管它显然很重要，但我们并不知道有任何公开或隐蔽的定向研究研究过这个问题。最后，这一建议的结果将对我们理解和建模注意和外显定向之间的关系具有重要的意义。

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.