fMRI investigation of response inhibition, emotion, impulsivity, and clinical high-risk behavior in adolescents

Abstract

High-risk behavior in adolescents is associated with injury, mental health problems, and poor outcomes in later life. Improved understanding of the neurobiology of high-risk behavior and impulsivity shows promise for informing clinical treatment and prevention as well as policy to better address high-risk behavior. We recruited 21 adolescents (age 14-17) with a wide range of high-risk behavior tendencies, including medically high-risk participants recruited from psychiatric clinics. Risk tendencies were assessed using the Adolescent Risk Behavior Screen (ARBS). ARBS risk scores correlated highly (0.78) with impulsivity scores from the Barratt Impulsivity scale (BIS). Participants underwent 4.7 Tesla functional magnetic resonance imaging (fMRI) while performing an emotional Go/NoGo task. This task presented an aversive or neutral distractor image simultaneously with each Go or NoGo stimulus. Risk behavior and impulsivity tendencies exhibited similar but not identical associations with fMRI activation patterns in prefrontal brain regions. We interpret these results as reflecting differences in response inhibition, emotional stimulus processing, and emotion regulation in relation to participant risk behavior tendencies and impulsivity levels. The results are consistent with high impulsivity playing an important role in determining high risk tendencies in this sample containing clinically high-risk adolescents.

Keywords: ARBS; adolescent; emotional Go/NoGo; high-risk behavior; impulsivity; response inhibition.

Figure 1

Emotional Go/NoGo task. (A) Each trial was either a Go or NoGo trial and featured an emotionally neutral or aversive distractor picture. (B) Example segment of two trials with 2–6 s fixation intertrial intervals (ITIs) interleaved. Figure reproduced from Brown et al. (2012).

Figure 2

ARBS risk scores vs. BIS impulsivity scores for 21 participants. The red line is the best fit linear regression of ARBS scores against BIS scores. Correlation between BIS and ARBS scores was 0.78 (significant, p = 3 × 10⁻⁵, t = 5.42, df = 19). BIS scores explained 59.7% of the variance in the ARBS scores.

Figure 3

Top row: Statistical t-map for response inhibition contrast (NoGo − Go, collapsed across distractor type). Red and blue regions, respectively, exhibited larger contrast magnitudes for NoGo and Go trials. All results p < 0.05 (corrected for multiple comparisons). Color bar indicates t-value scaling. Slice Z-coordinate in MNI space shown in upper-left. Axial images' left side corresponds to left side of brain. vlPFC: ventrolateral prefrontal cortex. Second row: Mean deconvolved timecourses for four trial types for regions outlined in green in first row. Error bars denote mean across all participants' standard error of mean activation time course values.

Figure 4

Top row: Statistical t-map for emotional valence contrast (aversive − neutral distractors, collapsed across Go/NoGo). Red and blue regions, respectively, exhibited larger contrast magnitudes for aversive and neutral distractor trials. All results p < 0.05 (corrected for multiple comparisons). Color bar indicates t-value scaling. Slice Y- or Z-coordinate in MNI space shown in upper-left. Images' left side corresponds to left side of brain. vlPFC: ventrolateral prefrontal cortex. Second row: Mean deconvolved timecourses for four trial types for regions outlined in green in first row. Error bars denote mean across all participants' standard error of mean activation time course values.

Figure 5

Top row: Statistical t-map for regression of ARBS risk scores against fMRI emotional valence contrast (aversive − neutral distractors). Red/yellow regions exhibited larger contrast magnitudes in participants with higher ARBS risk scores. All results p < 0.05 (corrected for multiple comparisons). Color bars indicate t-value scaling. Slice X- or Z-coordinate in MNI space shown in upper-left. Axial image's left side corresponds to left side of brain. MTG: middle temporal gyrus. Second row: Mean deconvolved timecourses for four trial types for region outlined in green in first row. Error bars denote mean across all participants' standard error of mean activation time course values. Timecourses denoted Low-Risk were computed from 11 low-risk participants with ARBS risk scores ≤ 13. Timecourses denoted High-Risk were computed from 10 high-risk participants with ARBS risk scores ≥17. Bottom row: Scatter plots show emotional valence contrast magnitude vs. participants' ARBS risk scores (left) and vs. BIS impulsivity scores (right) for right MTG region outlined in green in first row. Red line shows linear regression of contrast magnitude against participant ARBS or BIS scores.

Figure 6

Histogram of similarity measures between correlation patterns for ARBS and BIS scores. A correlation pattern captures the relationship between an instrument (ARBS or BIS scores) and fMRI contrast values. See Section 2.7 for details of correlation pattern and similarity measure computation. Values were computed from 10,000 iterations of bootstrap sampling.