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.Neuroscience of Rule-Guided Behavior Phần 6

Công tác chuyển đổi mô hình là một sự lựa chọn ưa thích để nghiên cứu cách thức con người đại diện và áp dụng các quy tắc. Những mô hình này bao gồm các thử nghiệm của hai bối cảnh nhiệm vụ khác nhau, với các quy tắc riêng của mình, giữa các đối tượng thường xuyên chuyển đổi. | This page intentionally left blank 11 Task-Switching in Human and Nonhuman Primates Understanding Rule Encoding and Control from Behavior to Single Neurons Gijsbert Stoet and Lawrence Snyder Task-switching paradigms are a favorite choice for studying how humans represent and apply rules. These paradigms consist of trials of two different task contexts each with its own rules between which subjects frequently switch. Measuring the difficulty subjects have when switching between tasks taps into a fundamental property of executive control that is the capacity to respond to stimuli according to task context. Although any biological organism can have a fixed response to sensory inputs it is nontrivial to process identical inputs in different ways depending on the task context. Task-switching paradigms are designed to study how subjects respond in the face of changing task contexts. In the last decade more than 400 studies using this paradigm have been published for an overview see Monsell 2003 . Most of these studies are about human task-switching. However unfortunately there are limits to what we can learn from humans. We can look at behavior and at regional brain metabolism but it is very difficult to study the individual neuronal level using invasive techniques. In this chapter we use rhesus monkeys as a model system to look at executive control at the neuronal level. A large number of studies have done something similar in the frontal lobes e.g. see Chapters 9 10 11 and 13 . We concentrate on the parietal lobe and show that parietal neurons play a critical role in executive control. The idea that the parietal lobe might play a role in executive control is surprising but not altogether unanticipated. After all the posterior parietal cortex PPC is an association area and thus a likely candidate for integrating different cortical processes. A number of brain imaging studies have focused on executive functions in the parietal cortex e.g. Sohn et al. 2000 Rushworth et .