Emotion Circuits in the Brain

Abstract

The field of neuroscience has, after a long period of looking the other way, again embraced emotion as an important research area. Much of the progress has come from studies of fear, and especially fear conditioning. This work has pinpointed the amygdala as an important component of the system involved in the acquisition, storage, and expression of fear memory and has elucidated in detail how stimuli enter, travel through, and exit the amygdala. Some progress has also been made in understanding the cellular and molecular mechanisms that underlie fear conditioning, and recent studies have also shown that the findings from experimental animals apply to the human brain. It is important to remember why this work on emotion succeeded where past efforts failed. It focused on a psychologically well-defined aspect of emotion, avoided vague and poorly defined concepts such as "affect," "hedonic tone," or "emotional feelings," and used a simple and straightforward experimental approach. With so much research being done in this area today, it is important that the mistakes of the past not be made again. It is also time to expand from this foundation into broader aspects of mind and behavior.

The late positive potential: A neural marker of the regulation of emotion-based approach-avoidance actions?

“…emotional dysregulation) is associated with a number of psychopathologies (Davidson, 1998(Davidson, , 2002Phillips, Ladouceur, & Drevets, 2008a, 2008b. Despite the importance of this ability, most studies of emotion-related responses focus on the perception and classification of emotional stimuli, rather than the regulation involved in the preparation to complete an appropriate regulated action (Burgdorf & Panksepp, 2006;Calder, Lawrence, & Young, 2001;LeDoux, 2000).…”

NMDA-dependent facilitation of corticostriatal plasticity by the amygdala

“…Although much evidence indicates that the amygdala is a critical site of plasticity for the acquisition of classically conditioned fear responses (16), the effects of the manipulations mentioned above seem to result from alterations of memory storage in other neuronal structures (8). For instance, it was shown that immediate postlearning injection of amphetamines in the BLA increases hippocampal-dependent storage of spatial information and striatal-dependent storage of response information.…”

Genetic influences on the neural basis of social cognition

“…We used an aversive loud sound as the unconditioned stimulus (Morris & Dolan 2004) and measured SCRs. Despite their very poor performance on the cognitive task requiring the accurate identification of negative facial expressions, females with Turner syndrome showed normal acquisition of fear conditioning, indicating that in this respect they had normal amygdala function (LeDoux 2000). There is evidence from this experiment that amygdala-related cognitive performance could be impaired, in the presence of intact autonomic responsiveness to a threatening stimulus.…”

“…AMYGDALA-CORTICAL FUNCTIONAL CONNECTIVITY AND PARANOIA Threatening or traumatic stimuli are probably processed in parallel by two distinct neural systems (Bechara et al 1995;LeDoux 2000). The subjective experience of fear relies upon amygdala-medial frontal activity (as well as autonomic arousal).…”

“…The amygdala plays a critical role in fear conditioning, which is a variant of Pavlovian classical conditioning (LeDoux 2000). The conditioned stimulus in a fearconditioning experiment with humans might involve a loud noise (the unconditioned stimulus), a negative facial expression (the conditioned stimulus) and an autonomic response, such as an increased skin conductance (the conditioned response).…”