Amygdala tuning from motivational relevance

成功地驾驭复杂的环境需要过程来确定情境需求背景下刺激的相对价值。最近的研究已经开始说明重要的认知和情感神经过程参与消除歧义的评价内涵的刺激和准备身体的行动。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性刺激，或者更普遍地参与处理消极情绪。研究表明，正性刺激和负性刺激一样，比中性刺激引起更大的杏仁核活动，这对特定于效价的概念化提出了质疑。最近的研究表明，杏仁核的功能可能代表了一个更普遍的警惕动机相关的刺激，无论效价。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。由于多个目标可能很重要，因此具体需求、目标和价值观的突出性和优先性对于形成应对措施很重要。动机的偶然性，以及给定刺激的相关性，可能会不断变化。根据这种观点，杏仁核的处理可能反映了一种早期的刺激评估检查，它决定了一个刺激与一个人正在进行的动机状态的相关性。因此，对于不同情况下的不同人来说，杏仁核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整的。拟议的研究利用杏仁核的高分辨率功能磁共振成像扫描以及最先进的分析工具（多体元模式识别和连接分析），以更好地了解目标如何塑造杏仁核表征，以及这种塑造对以后大脑处理的影响。

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.