Neural substrates of attention and orienting

描述（由申请人提供）：视觉定向既可以通过认知控制自发产生，也可以通过刺激驱动的过程从外部（反射性）唤起。此外，定向可能是隐蔽的（注意力转移）或明显的（眼球运动）。我们提出了注意和定向的强直抑制模型，详细说明了这些过程及其相互作用的特定神经基质。鉴于帕金森病（PD）中已知的基底神经节和额叶的破坏，该人群代表了该模型的理想测试。因此，该提案将对PD的定向进行系统调查，并将是第一个全面检查该人群在这两个维度（即自愿与反射，隐蔽与公开）上的表现的研究。在第一部分中，我们将比较PD和对照受试者的自愿和反射性显性定向。根据我们和其他人之前的研究，我们预计PD受试者在自愿眼动方面缺乏，但在某些条件下，在反射性眼动方面更有效。在第二部分中，我们将研究工作记忆缺陷与无法抑制无关信息在解释PD中较差的自愿表现方面的相对重要性，这两个因素通常被认为是导致自愿任务表现不佳的可能原因。提案的第三部分将比较PD和对照受试者的自愿和反射性注意。在PD的研究中，没有独立于自愿空间注意的反身性空间注意。本研究的最后一部分将研究不同感觉运动转换对PD患者视觉空间注意的影响。我们之前发现，简单或直接的刺激-反应（S-R）映射与更复杂的间接S-R映射表现出不同的注意时间过程。PD患者在某些视觉运动转化方面存在困难。因此，我们将研究和比较S-R映射对PD和对照受试者注意范式的影响。所有拟制的实验都将系统地操纵PD受试者的用药状态，以阐明药物在缓解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检查了这个问题。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.