Amygdala tuning from motivational relevance

成功地驾驭复杂环境需要在情境需求的背景下确定刺激的相对价值。最近的研究已经开始阐明重要的认知和情感神经过程，这些过程涉及消除刺激的评估内涵的歧义，并为身体的行动做好准备。不同方法论的一致证据表明，杏仁核与编码和处理刺激的情感属性特别相关。最初的研究表明，杏仁核专门参与检测威胁性刺激，或者更普遍地参与处理消极情绪。这种价态特有的概念受到了一些研究的质疑，研究表明，与负面刺激一样，积极刺激比中性刺激能激发更大的杏仁核活动。最近的研究表明，杏仁核的功能可能代表着对动机相关刺激的更普遍的警觉，而不考虑价态。刺激的动机相关性可以被定义为对个体的任何瞬时动机状态的有用性。因为多个目标可能很重要，所以特定需求、目标和价值观的突出程度和优先顺序对于形成响应非常重要。激励的偶然性，以及特定刺激的相关性，可能会持续变化。根据这一观点，杏仁核的处理可能反映了一种早期的刺激评估检查，该检查确定了刺激与一个人正在进行的动机状态的相关性。因此，对于处于不同情况下的不同人来说，杏仁核的激活可能是他们情感反应的一部分，但这些反应的结果可能截然不同。在过去的几年里，我的实验室使用功能磁共振成像(FMRI)来研究杏仁核是如何被这些慢性和情景因素塑造和调整的。拟议的研究利用对杏仁核的高分辨率fMRI扫描，以及最先进的分析工具(多体素模式识别和连通性分析)，以更好地了解杏仁核的表征是如何由目标塑造的，以及这种塑造对后来的大脑处理的影响。

Successfully navigating complex environments requires processes to determine the relative value of stimuli in the context of situational demands. Recent research has begun to illustrate the important cognitive and affective neural processes involved in disambiguating the evaluative connotations of stimuli and preparing the body for action. Convergent evidence across methodologies suggests that the amygdala is particularly relevant for encoding and processing the affective properties of stimuli. Initial research suggested that the amygdala is specifically involved in detecting threatening stimuli, or is more generally engaged in processing negativity. This valence-specific conceptualization has been called into question by studies showing that positive, like negative, stimuli evoke greater amygdala activity than neutral stimuli. More recent studies have suggested that amygdala function may represent a more general vigilance for motivationally relevant stimuli, regardless of valence. Motivational relevance of stimuli can be defined as usefulness for any momentary motivational state of the individual. Because multiple goals can be important, the salience and priority of specific needs, goals, and values are important for shaping a response. Motivational contingencies, and thus the relevance of a given stimulus, may change continuously. On this view, amygdala processing may reflect an early stimulus evaluation check that determines the relevance of a stimulus with respect to one's ongoing motivational state. Thus, for different people in different situations, amygdala activation may be part of their affective responses, but the outcomes of those responses may be vastly different. Over the past several years, my lab has used functional Magnetic Resonance Imaging (fMRI) to investigate how the amygdala is shaped and tuned by such chronic and situational factors. The proposed studies utilize high-resolution fMRI scanning of the amygdala alongside state-of-the-art analysis tools (multivoxel pattern recognition and connectivity analyses) to better understand how amygdala representations are shaped by goals, and the implications of this shaping for later brain processing.