Disrupted avoidance learning in functional neurological disorder: Implications for harm avoidance theories.

Background: Functional neurological disorder (FND) is an elusive disorder characterized by unexplained neurological symptoms alongside aberrant cognitive processing and negative affect, often associated with amygdala reactivity.

Methods: We examined the effect of negative conditioning on cognitive function and amygdala reactivity in 25 FND patients and 20 healthy volunteers (HV). Participants were first conditioned to stimuli paired with negative affective or neutral (CS +/CS -) information.

Serotonergic, brain volume and attentional correlates of trait anxiety in primates.

Trait anxiety is a risk factor for the development and maintenance of affective disorders, and insights into the underlying brain mechanisms are vital for improving treatment and prevention strategies. Translational studies in non-human primates, where targeted neurochemical and genetic manipulations can be made, are critical in view of their close neuroanatomical similarity to humans in brain regions implicated in trait anxiety. Thus, we characterised the serotonergic and regional brain volume correlates of trait-like anxiety in the marmoset monkey.

Lesions of ventrolateral prefrontal or anterior orbitofrontal cortex in primates heighten negative emotion.

Background: Heightened fear and anxiety are core symptoms of a variety of neuropsychiatric disorders. They are associated with structural and activity changes throughout neural circuitry that includes the ventral and medial prefrontal cortices (PFC), the amygdala, and hippocampus. Although the contributions of the medial PFC, amygdala, and hippocampus to fear and anxiety have been studied extensively with animal models, the selective roles of the ventral PFC-including the ventrolateral prefrontal cortex (vlPFC) and orbitofrontal cortex-are poorly understood.

Serotonin at the level of the amygdala and orbitofrontal cortex modulates distinct aspects of positive emotion in primates.

Impaired top-down regulation of the amygdala, and its modulation by serotonin (5-HT), is strongly implicated in the dysregulation of negative emotion that characterizes a number of affective disorders. However, the contribution of these mechanisms to the regulation of positive emotion is not well understood. This study investigated the role of 5-HT within the amygdala and the orbitofrontal cortex (OFC), on the expression of appetitive Pavlovian conditioned emotional responses and their reversal in a primate, the common marmoset.

Autonomic, behavioral, and neural analyses of mild conditioned negative affect in marmosets.

Avoidance and alerting behaviors and accompanying physiological responses, including changes in heart rate (HR), are core components of negative emotion. Investigations into the neural mechanisms underlying the regulation and integration of these responses require animal models that simultaneously measure both the physiological and behavioral components of emotion. A primate model is of particular importance in view of the well developed prefrontal cortex of primates, and this region's critical role in emotion regulation and the etiology of affective disorders.