Amygdala tuning from motivational relevance

点击翻译按钮获取中文摘要

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.