Tuesday, December 23, 2008

Enhanced perception of threat during limited attention

This open access article from Dolan's and collaborators builds on previous studies on the role of the amygdala in pre-attentive processing of potential threats, noting parts of the brain that become active during threat identification during periods of compromised attention. Their abstract:
The ability to process stimuli that convey potential threat, under conditions of limited attentional resources, confers adaptive advantages. This study examined the neurobiology underpinnings of this capacity. Employing an attentional blink paradigm, in conjunction with functional magnetic resonance imaging, we manipulated the salience of the second of 2 face target stimuli (T2), by varying emotionality. Behaviorally, fearful T2 faces were identified significantly more than neutral faces. Activity in fusiform face area increased with correct identification of T2 faces. Enhanced activity in rostral anterior cingulate cortex (rACC) accounted for the benefit in detection of fearful stimuli reflected in a significant interaction between target valence and correct identification. Thus, under conditions of limited attention resources activation in rACC correlated with enhanced processing of emotional stimuli. We suggest that these data support a model in which a prefrontal "gate" mechanism controls conscious access of emotional information under conditions of limited attentional resources.

In the same issue of Cerebral Cortex, another Dolan collaboration uses a masked face priming paradigm to show that face responsive regions of the brain become active in the absence of awareness of faces that are presented.

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