Beta coherence within human ventromedial prefrontal cortex precedes affective value choices

Ventromedial prefrontal cortex (vmPFC) forms a core region of larger brain circuits that assign value to sensory inputs and interfaces motivational and cognitive dominated brain processes. This network function of the vmPFC could be realized by synchronizing local activity at time scales that are shared by connected brain areas, but it is unknown whether vmPFC circuitry engages in functionally specific synchronization. Here, we recorded in human subcallosal vmPFC while subjects engaged in an emotion tracking task that required the assignment of positive or negative affective value to ambiguous (happy-sad) facial expressions. We found that vmPFC engages in low beta-band (15-20 Hz) coherent activation just before subjects subjectively judged ambiguous facial expressions as conveying negative valence ('sad') information, but not before positive valence ('happy') judgments. The predictive beta coherence emerged particularly for conflicting rather than pure emotional facial cues and dissipated slowly after the choice was made. These results suggest that 15-20 Hz coherent activity within vmPFC marks a functional signature of a valuation process that informs categorical affective choices. We hypothesize that coherent beta band activation signifies functional interactions to anatomical vmPFC projection targets, raising the possibility that dysfunctional biases in affective valuation and an enhanced decision conflict in clinical depression could be indexed by alterations of beta coherent network activation. (C) 2013 Elsevier Inc. All rights reserved.