Right dorsolateral prefrontal cortical activity and behavioral inhibition

Abstract

Individuals show marked variation in their responses to threat. Such individual differences in behavioral inhibition play a profound role in mental and physical well-being. Behavioral inhibition is thought to reflect variation in the sensitivity of a distributed neural system responsible for generating anxiety and organizing defensive responses to threat and punishment. Although progress has been made in identifying the key constituents of this behavioral inhibition system in humans, the involvement of dorsolateral prefrontal cortex (DLPFC) remains unclear. Here, we acquired self-reported Behavioral Inhibition System Sensitivity scores and high-resolution electroencephalography from a large sample (n= 51). Using the enhanced spatial resolution afforded by source modeling techniques, we show that individuals with greater tonic (resting) activity in right-posterior DLPFC rate themselves as more behaviorally inhibited. This observation provides novel support for recent conceptualizations of behavioral inhibition and clues to the mechanisms that might underlie variation in threat-induced negative affect.

Figure 1. Relations between individual differences in the Behavioral Inhibition System (BIS) scale and mid-frontal EEG asymmetry

Asymmetry was computed as right minus left mean power density, log₁₀(μV²/Hz), for the alpha-1 (8-10Hz) band.

Figure 2. Relations between individual differences in BIS and tonic activity in right dorsolateral prefrontal cortex (dlPFC)

(A) Cluster lies at the intersection of the precentral and inferior frontal sulci, encompassing the right posterior middle frontal and inferior frontal gyri and including the Inferior Frontal Junction (IFJ), cluster corrected-p=0.02. Cross-hair shows the location in right posterior dlPFC of the peak correlation. “L” and “R” indicate the left- and right-hemispheres, respectively. (B) Scatter-plot depicting the peak partial correlation in right posterior dlPFC (area 9/46v), r(48)=-0.37, uncorrected-p=.003. Units reflect cortical current density, log₁₀(A/m²).