An Investigation of Attentional Networks, the Locus Coeruleus - Norepinephrine System, and Autism and ADHD Traits.

Abstract

Purpose: Attention is proposed to consist of three discrete neurofunctional networks, though evidence suggests that two of these - the alerting and cognitive control networks - are interdependent. The neural mechanism(s) underlying this interdependence have not been identified; however, the locus coeruleus - norepinephrine (LC-NE) system may provide a potential explanation for this interaction. Further, both alerting-cognitive control interdependence and LC-NE activity may be altered in autistic individuals, and thus may provide a unique window into the relationship between the LC-NE system and network interdependence. The objective of the current study was to utilize electrophysiological and pupillary indices of LC-NE activity to examine the associations between attentional network interdependence, LC-NE activity, and autism and ADHD traits.

Methods: A total of 77 neurotypical undergraduate students completed two tasks: (1) a resting eye-tracking task to measure pupil diameter (tonic LC activity), and (2) a cued-flanker task to measure cue-related pupil diameter response (cue PDR; phasic LC activity) and attentional network interdependence using behavioral, electrophysiological, and pupillometric indices. Autistic and ADHD traits were measured by self-reported questionnaires.

Results: Consistent with prior reports, our behavioral and electrophysiological results support network interdependence. Phasic LC activity was positively related to alerting-cognitive control interdependence. Finally, the tonic and phasic LC-NE indices were linked to distinct ADHD subscales but not to autistic traits.

Conclusion: These findings expand our understanding of neurofunctional mechanism associated with alerting-cognitive control interdependence and demonstrate that LC-NE activation may be associated with ADHD rather than with autistic traits.