The dynamic interactions between the amygdala and the medial prefrontal cortex (mPFC) are usefully conceptualized as a circuit that both allows us to react automatically to biologically relevant predictive stimuli as well as regulate these reactions when the situation calls for it. In this review, we will begin by discussing the role of this amygdala-mPFC circuitry in the conditioning and extinction of aversive learning in animals. We will then relate these data to emotional regulation paradigms in humans. Finally, we will consider how these processes are compromised in normal and pathological anxiety. We conclude that the capacity for efficient crosstalk between the amygdala and the mPFC, which is represented as the strength of the amygdala-mPFC circuitry, is crucial to beneficial outcomes in terms of reported anxiety.

SummaryHuman action is strongly influenced by expectations of pleasure. Making decisions, ranging from which products to buy to which job offer to accept, requires an estimation of how good (or bad) the likely outcomes will make us feel [1]. Yet, little is known about the biological basis of subjective estimations of future hedonic reactions. Here, we show that administration of a drug that enhances dopaminergic function (dihydroxy-L-phenylalanine; L-DOPA) during the imaginative construction of positive future life events subsequently enhances estimates of the hedonic pleasure to be derived from these same events. These findings provide the first direct evidence for the role of dopamine in the modulation of subjective hedonic expectations in humans.

The aim of this review is to show the fruitfulness of using images of facial expressions as experimental stimuli in order to study how neural systems support biologically relevant learning as it relates to social interactions. Here we consider facial expressions as naturally conditioned stimuli which, when presented in experimental paradigms, evoke activation in amygdala–prefrontal neural circuits that serve to decipher the predictive meaning of the expressions. Facial expressions offer a relatively innocuous strategy with which to investigate these normal variations in affective information processing, as well as the promise of elucidating what role the aberrance of such processing might play in emotional disorders.

Anxiety impacts the quality of everyday life and may facilitate the development of affective disorders, possibly through concurrent alterations in neural circuitry. Findings from multimodal neuroimaging studies suggest that trait-anxious individuals may have a reduced capacity for efficient communication between the amygdala and the ventral prefrontal cortex (vPFC). A diffusion-weighted imaging protocol with 61 directions was used to identify lateral and medial amygdala-vPFC white matter pathways. The structural integrity of both pathways was inversely correlated with self-reported levels of trait anxiety. When this mask from our first dataset was then applied to an independent validation dataset, both pathways again showed a consistent inverse relationship with trait anxiety. Importantly, a moderating effect of sex was found, demonstrating that the observed brain-anxiety relationship was stronger in females. These data reveal a potential neuroanatomical mediator of previously documented functional alterations in amygdala-prefrontal connectivity that is associated with trait anxiety, which might prove informative for future studies of psychopathology.

The contribution of context to phoneme perception is a subject of extensive study. In recent years, while the perception of phonemes in and out of context has become characterized as well-understood, new studies have emerged to challenge prevailing wisdom. Findings derived from rigorously controlled stimuli have failed to hold up when tested against continuous or more naturalistic speech, and vowels produced in isolation have been shown to possess different frequencies than vowels in spontaneous speech. In the present study, we examine the effect of context on vowel recognition, via stimuli taken directly from natural continuous speech in an audiobook. All tested vowel sounds, except /EH/, were better recognized with surrounding context than in isolation, affirming the resilience of findings from past studies.

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