NEURAL MECHANISMS OF VISUAL PERCEPTION

这个子项目是许多利用 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 我们提出了一些实验来检验有关大脑决策能力的神经机制的假设。我们的实验解决了大脑将视觉皮层神经元代表的感觉信息转换为决定这些信息对计划行为的意义的机制。我们发现，猕猴的联合皮层神经元代表了这种选择和反对另一种选择的证据的积累。今年，我们证明了当环境控制证据的可用性时，解释选择和决策时间的机制也适用。令人惊讶的发现是，大脑的行为就像在选择反应时间实验中一样。它在准备就绪时终止决策，尽管有额外的信息可用（Kiani等人，2008）。 我们还完成了一项关于当有两种以上选择时决策机制的研究（Churchland et al，2008）。今年完成了与WaNPRC以外的研究者合作进行的几项理论研究（Wong et al，2008; Beck et al，2008; Ganguli et al，2008）。 决策弥合了感觉和行为之间的差距。几乎所有的非反射行为都需要大脑利用其感觉皮层来指导未来的行为。因此，我们所研究的简单决策的神经机制可能有助于深入了解更复杂的认知策略。我们的实验最终为影响感知，计划和推理的精神障碍的原因和治疗提供了新的见解。

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. We proposed experiments that test hypotheses about the neural mechanisms that underlie the brain's ability to make decisions. Our experiments address the mechanism used by the brain to convert sensory information represented by neurons in the visual cortex to a decision about what this information means for purposes of planning behavior. We showed that neurons in the association cortex of the macaque represent the accumulation of this evidence for one choice and against an alternative. This year, we demonstrated that the mechanism that explains choice and decision time also applies when the environment controls the availability of evidence. The surprising finding is that the brain acts as it would in a choice-reaction time experiment. It terminates the decision when ready despite the availability of addition information (Kiani et al, 2008). We have also completed a study of the mechanism to decision-making when there are more than 2 options (Churchland et al, 2008). Several theoretical studies performed in collaboration with investigators outside the WaNPRC were completed this year (Wong et al, 2008; Beck et al, 2008; Ganguli et al, 2008). Decision-making bridges the gap between sensation and behavior. Nearly all non-reflexive behaviors require the brain to draw upon its sensory cortex to guide future behavior. Thus, the neural mechanisms for the simple decisions we study are likely to lend insight into more complex cognitive strategies. Our experiments ultimately furnish new insights into the causes and treatments of mental disorders affecting perception, planning and reasoning.