The role of anterior prefrontal cortex (area 10) in face-to-face deception measured with fNIRS

Abstract

Anterior prefrontal cortex (PFC, Brodmann area 10) activations are often, but not always, found in neuroimaging studies investigating deception, and the precise role of this area remains unclear. To explore the role of the PFC in face-to-face deception, we invited pairs of participants to play a card game involving lying and lie detection while we used functional near infrared spectroscopy (fNIRS) to record brain activity in the PFC. Participants could win points for successfully lying about the value of their cards or for detecting lies. We contrasted patterns of brain activation when the participants either told the truth or lied, when they were either forced into this or did so voluntarily and when they either succeeded or failed to detect a lie. Activation in the anterior PFC was found in both lie production and detection, unrelated to reward. Analysis of cross-brain activation patterns between participants identified areas of the PFC where the lead player's brain activity synchronized their partner's later brain activity. These results suggest that during situations that involve close interpersonal interaction, the anterior PFC supports processing widely involved in deception, possibly relating to the demands of monitoring one's own and other people's behaviour.

Keywords: anterior prefrontal cortex; deception; fNIRS; face-to-face social interactions; hyperscanning.

Fig. 1

Experimental set-up. Two rows of eight cards each were placed in front of the participants. In this representative round, the participant on the left has the role of Informer and makes a truthful or untruthful statement on the value of her card respect to the other participant’s corresponding card; the participant on the right is the Guesser and has to guess whether the Informer told the truth or lied. fNIRS (LIGHTNIRS, Shimadzu Corp., Kyoto, Japan) was used to monitor both participants’ brain activity while playing cards.

Fig. 2

Schematic representation of sources (red circles) and detectors (blue circles) placement. Sources and detectors are arranged in a 8 × 2 configuration creating 22 measurement channels (white circles).

Fig. 3

t-values maps corresponding to the group level GLM results on the activation signal for the 4 lying contrast. Significant channels (p < 0.05) at the uncorrected level are circled in white, while significant channels surviving the correction for multiple comparisons (i.e. two or more adjacent channels) are marked with asterisks (Southgate et al., 2014).

Fig. 4

t-Values maps corresponding to the group level GLM results on the activation signal for the effect of instructions (A and B) and the overall task contrasts (C–E). Significant channels (p < 0.05) at the uncorrected level are circled in white, while significant channels surviving the correction for multiple comparisons (i.e. two or more adjacent channels) are marked with asterisks (Southgate et al., 2014).

Fig. 5

Brain-to-brain analysis group results. The magenta boxes include the t-test results on the group -values at different time lags () that revealed a significant coupling between the Informer and the Guesser’s brain in the anterior and left lateral rostral PFC (Brodmann area 10) (channels 4 and 13; red dot; p < 0.05). The blue line represents the t-values at different time lags (). The significant Informer–Guesser coupling was found at , which however did not survive the FDR correction. The light blue boxes include the non-parametric permutation (N = 1000) results. The black line represents the average -values across the 1000 permutations and at different time lags (), while the yellow shaded area highlights the 95% confidence interval (2.5 and 97.5% percentiles). The significant Informer–Guesser coupling corresponds to the -value exceeding the confidence interval. This occurs for (red dot) in the anterior and left lateral rostral PFC (channels 4 and 13; principally, Brodmann area 10).