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Measuring context in human prefrontal cortex.

機(jī)譯：測(cè)量人類前額葉皮層的背景。

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摘要

Human behavior is dependent on flexibility whenever response alternatives are available. For instance, finishing a work project to meet a deadline may require a delay of more pleasant activities such as reading a favorite book. The flexibility to choose working on the project over reading a book is determined by context: the circumstances in which a response is selected (e.g., a project deadline). The aim of the present research was to identify how context is represented as neural activity, a question that is relatively undefined in the human brain. The approach I adopted to study this question was based on the Guided Activation Theory of cognitive control, which posits that activation in the prefrontal cortex (PFC) represents abstractions of context, serving to bias activity in posterior and sub-cortical regions responsible for executing a behavior. I conducted three studies, guided by this framework. In the first study I used electroencephalography to measure the onset of context updating. Voltage recorded at the surface of the brain showed a positive deflection at 180--200 ms, related to context and localized to PFC, confirming that this region is involved in context processing. In the second study I developed a behavioral index to assess context retrieval when anticipating response selection. This index was designed to maximize task specificity, the ability to differentiate context among similar tasks and to dissociate it from non-contextual cognitive processes. Finally, in the third study I used this behavioral index and functional magnetic resonance imaging to identify neural representations corresponding to each of four tasks. These representations included task specific regions in both posterior cortex and PFC. The posterior activations were consistent with what is known about the neural substrates involved in performing each task whereas the PFC regions were consistent with anatomical connections between these regions and PFC. The results of this research provide comprehensive evidence consistent with a role of PFC in representation of context, thus consistent with the Guided Activation Theory, and highlight that an exciting avenue for future research will be to address how interactions between regions implement vs. represent context.
機(jī)譯：只要有其他應(yīng)對(duì)方法，人類的行為就取決于靈活性。例如，完成一個(gè)工作項(xiàng)目以滿足最后期限可能需要延遲一些更愉快的活動(dòng)，例如閱讀喜歡的書(shū)。通過(guò)閱讀來(lái)選擇在項(xiàng)目上從事項(xiàng)目的靈活性取決于上下文：選擇響應(yīng)的情況（例如，項(xiàng)目截止日期）。本研究的目的是確定背景如何表示為神經(jīng)活動(dòng)，這是人腦中相對(duì)不確定的問(wèn)題。我用于研究此問(wèn)題的方法基于認(rèn)知控制的引導(dǎo)激活理論，該理論認(rèn)為前額葉皮層（PFC）中的激活表示背景的抽象，有助于使后皮層和皮層下區(qū)域的活動(dòng)產(chǎn)生偏差。行為。在此框架的指導(dǎo)下，我進(jìn)行了三項(xiàng)研究。在第一個(gè)研究中，我使用腦電圖來(lái)測(cè)量上下文更新的開(kāi)始時(shí)間。大腦表面記錄的電壓在180--200 ms處顯示正偏，與上下文有關(guān)并局限于PFC，證實(shí)該區(qū)域參與了上下文處理。在第二項(xiàng)研究中，我開(kāi)發(fā)了一個(gè)行為指數(shù)，以在預(yù)期響應(yīng)選擇時(shí)評(píng)估上下文檢索。該索引旨在最大程度地提高任務(wù)的特異性，區(qū)分相似任務(wù)之間的上下文并將其與非上下文認(rèn)知過(guò)程分離的能力。最后，在第三項(xiàng)研究中，我使用了這種行為指數(shù)和功能磁共振成像來(lái)識(shí)別與四個(gè)任務(wù)中的每個(gè)任務(wù)相對(duì)應(yīng)的神經(jīng)表征。這些表示包括后皮質(zhì)和PFC中的任務(wù)特定區(qū)域。后部激活與執(zhí)行每個(gè)任務(wù)所涉及的神經(jīng)基質(zhì)有關(guān)，而PFC區(qū)域與這些區(qū)域與PFC之間的解剖學(xué)連接一致。這項(xiàng)研究的結(jié)果提供了與PFC在情境表示中的作用一致的全面證據(jù)，因此與“引導(dǎo)激活理論”相一致，并強(qiáng)調(diào)指出，未來(lái)研究的一個(gè)令人興奮的途徑將是解決區(qū)域之間的交互如何實(shí)現(xiàn)與代表情境。

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  • 作者

    Lenartowicz, Agatha.;

  • 作者單位

    Princeton University.;

  • 授予單位 Princeton University.;
  • 學(xué)科 Biology Neuroscience.;Psychology Cognitive.
  • 學(xué)位 Ph.D.
  • 年度 2008
  • 頁(yè)碼 166 p.
  • 總頁(yè)數(shù) 166
  • 原文格式 PDF
  • 正文語(yǔ)種 eng
  • 中圖分類
  • 關(guān)鍵詞

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