Amygdala tuning from motivational relevance

成功地在复杂的环境中导航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说明重要的认知和情感神经过程涉及消除刺激的评价内涵歧义和准备身体的行动。各种方法的趋同证据表明，杏仁核与编码和处理刺激的情感特性特别相关。最初的研究表明，杏仁核专门参与检测威胁刺激，或者更普遍地参与处理消极情绪。研究表明，积极刺激和消极刺激一样，会比中性刺激唤起更大的杏仁核活动，这一观点受到了质疑。最近的研究表明，杏仁核的功能可能代表了对动机相关刺激的更普遍的警觉性，而不管其效价如何。刺激的动机相关性可以定义为对个体任何瞬间动机状态的有用性。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性和优先级对于形成响应很重要。动机偶然性，也就是给定刺激的相关性，可能会不断变化。根据这一观点，杏仁核加工可能反映了早期刺激评估检查，该检查决定了刺激与一个人正在进行的动机状态的相关性。因此，对于不同的人在不同的情况下，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大不相同。在过去的几年里，我的实验室使用功能性磁共振成像（fMRI）来研究杏仁核是如何被这些慢性和情境因素塑造和调节的。本研究利用高分辨率的核磁共振成像扫描杏仁核以及最先进的分析工具（多体素模式识别和连通性分析）来更好地理解杏仁核表征是如何被目标塑造的，以及这种塑造对后期大脑处理的影响。

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.