Irritability uniquely predicts prefrontal cortex activation during preschool inhibitory control among all temperament domains: A LASSO approach

Abstract

Temperament, defined as individual variation in the reactivity and regulation of emotional, motor, and attentional processes, has been shown to influence emotional and cognitive development during the preschool period (ages 4-5). While relationships between temperament and neural activity have been investigated previously, these have typically investigated individual temperament dimensions selected ad hoc. Since significant correlations exist between various temperament dimensions, it remains unclear whether these findings would replicate while analyzing all temperament dimensions simultaneously. Using functional near infrared spectroscopy (fNIRS), 4-5-year-old children (N = 118) were administered a Go/No-Go task to assess prefrontal cortex activation during inhibitory control. The relationship between PFC activation and all 15 temperament domains defined by the Children's Behavior Questionnaire (CBQ) was assessed using automatic feature selection via LASSO regression. Results indicate that only the Anger/Frustration dimension was predictive of activation during the inhibitory control task. These findings support previous work showing relationships between irritability and prefrontal activation during executive function and extend those findings by demonstrating the specificity of the activation-irritability relationship among temperament dimensions.

Keywords: Functional near-infrared spectroscopy (fNIRS); Inhibitory control; Irritability; PFC; Preschool; Temperament.

Figure 1.. Go/No-go task design

Stimuli in the ‘Control’ blocks were umbrellas, which were all targets (‘go’). In the ‘Inhibition’ block sun images served as targets (‘go’) and infrequent rain images were non-targets (‘no-go’).

Figure 2.. Probe configuration

The probe is visualized on the surface of the scalp after registration to the Colin27 atlas. Red spheres are optical sources, blue spheres are detectors, and green connections are measurement channels. The probe covered the anterior portion of bilateral inferior frontal gyrus (IFG), and middle frontal gyrus (MFG). Positioning was performed using the 10–20 coordinate system by placing the dorsomedial sources over AF3/AF4, and the ventromedial sources over Fp1/Fp2.

Figure 3.. Go/No-go activation

Activation is shown for the ‘Inhibition’ and ‘Control’ conditions, as well as the ‘Inhibition’-’Control’ contrast. All images are thresholded at p<.05, with Benjamini-Hochberg FDR correction for the number of channels.

Figure 4.. IC-related reaction time predicts activation

The change in reaction time during the Go/No-go (i.e., ‘Inhibition’-’Control’) predicted the change in PFC activation during inhibitory control (r(115)=.190, p<.05). Size of points reflects the robust regression weights (i.e., from extreme low or high activation levels). Green shaded area reflects the 95% prediction confidence interval.

Figure 5.. Model selection using LASSO

Bar plot showing the maximum value of lambda for each of the whitened temperament domains in the LASSO model. The red dashed line reflects the cross-validation-derived threshold for variable inclusion. The LASSO model selected only the Anger/Frustration dimension.

Figure 6.. Anger/Frustration predicts inhibitory control activation

Follow-up robust regression analysis of the dimensions selected by the LASSO model revealed a significant positive relationship between Anger/Frustration and activation (r(103)=.282; p<.01). Size of points reflects the robust regression weights. Green shaded area reflects the 95% prediction confidence interval.