title: Effective connectivity of ascending and descending frontalthalamic pathways during sustained attention: Complex brain network interactions in adolescence.
abstract: Frontal-thalamic interactions are crucial for bottom-up gating and top-down control, yet have not been well studied from brain network perspectives. We applied network modeling of fMRI signals [dynamic causal modeling (DCM)] to investigate frontal-thalamic interactions during an attention task with parametrically varying levels of demand. fMRI was collected while subjects participated in a sustained continuous performance task with low and high attention demands. 162 competing model architectures were employed in DCM to evaluate hypotheses on bilateral frontal-thalamic connections and their modulation by attention demand, selected at a second level using Bayesian model selection. The model architecture evinced significant contextual modulation by attention of ascending (thalamus → dPFC) and descending (dPFC → thalamus) pathways. However, modulation of these pathways was asymmetric: while positive modulation of the ascending pathway was comparable across attention demand, modulation of the descending pathway was significantly greater when attention demands were increased. Increased modulation of the (dPFC → thalamus) pathway in response to increased attention demand constitutes novel evidence of attention-related gain in the connectivity of the descending attention pathway. By comparison demand-independent modulation of the ascending (thalamus → dPFC) pathway suggests unbiased thalamic inputs to the cortex in the context of the paradigm. Hum Brain Mapp 37:2557-2570, 2016. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Brain Imaging Research Division, Department of Psychiatry and Behavioral Neurosciences, Wayne State University School of Medicine, Tolan Park Medical Building, Suite 5B, Detroit, Michigan, 48201.
authors.forename: Pranav
authors.initials: P
authors.lastname: Jagtap
authors.affiliation: Brain Imaging Research Division, Department of Psychiatry and Behavioral Neurosciences, Wayne State University School of Medicine, Tolan Park Medical Building, Suite 5B, Detroit, Michigan, 48201.
authors.forename: Vaibhav A
authors.initials: VA
authors.lastname: Diwadkar
mesh_terms: D000293:Adolescent; D001288:Attention / Q000502:physiology*; D001499:Bayes Theorem; D001931:Brain Mapping; D002648:Child; D005260:Female; D005625:Frontal Lobe / Q000000981:diagnostic imaging / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008959:Models, Neurological; D009434:Neural Pathways / Q000000981:diagnostic imaging / Q000502:physiology; D009483:Neuropsychological Tests; D000297:Psychology, Adolescent; D013788:Thalamus / Q000000981:diagnostic imaging / Q000502:physiology*; D055815:Young Adult
keywords: adolescence; dynamic causal modeling; fMRI; prefrontal cortex; sustained attention; thalamus