Abnormal Functional Connectivity in Children with Attention-Deficit/Hyperactivity Disorder

Abstract

Background Attention-deficit/hyperactivity disorder (ADHD) is typically characterized by symptoms of inattention and hyperactivity/impulsivity, but there is increased recognition of a motivation deficit too. This neuropathology may reflect dysfunction of both attention and reward-motivation networks. Methods To test this hypothesis, we compared the functional connectivity density between 247 ADHD and 304 typically developing control children from a public magnetic resonance imaging database. We quantified short- and long-range functional connectivity density in the brain using an ultrafast data-driven approach. Results Children with ADHD had lower connectivity (short- and long-range) in regions of the dorsal attention (superior parietal cortex) and default-mode (precuneus) networks and in cerebellum and higher connectivity (short-range) in reward-motivation regions (ventral striatum and orbitofrontal cortex) than control subjects. In ADHD children, the orbitofrontal cortex (region involved in salience attribution) had higher connectivity with reward-motivation regions (striatum and anterior cingulate) and lower connectivity with superior parietal cortex (region involved in attention processing). Conclusions The enhanced connectivity within reward-motivation regions and their decreased connectivity with regions from the default-mode and dorsal attention networks suggest impaired interactions between control and reward pathways in ADHD that might underlie attention and motivation deficits in ADHD.

Lag in maturation of the brain’s intrinsic functional architecture in attention-deficit/hyperactivity disorder

“…According to current theoretical models (19,20), inattention in ADHD involves altered competitive balance between (i) default network, an ICN implicated in internally directed mentation (21,22); and (ii) several task-positive ICNs (TPNs), including dorsal attention network (DAN), ventral attention network (VAN), and frontoparietal network (FPN), which are involved in cognitively demanding externally focused processing. Consistent with these models, previous resting state fMRI studies in ADHD have reliably found abnormalities in functional connections within DMN (23,24) and in its interconnections with TPNs (25)(26)(27). Importantly, however, it is not currently known whether these abnormalities reliably observed in ADHD are linked to maturational lag.…”

Inter-hemispherical asymmetry in default-mode functional connectivity and BAIAP2 gene are associated with anger expression in ADHD adults

“…The DMN as the hallmark of resting state has been found altered in many neurological and psychiatric disorders, such as, among all, schizophrenia (Stephan et al, 2009;Woodward et al, 2011;Guo et al, 2014), mild cognitive impairment (Sinanaj et al, 2015) and ADHD (Sonuga-Barke and Castellanos, 2007;Castellanos et al, 2008;Fair et al, 2010;Tomasi and Volkow, 2012;Di Martino et al, 2013). Based on previous reports of abnormal laterality of the ADHD brain (Dennis and Thompson, 2013;Shang et al, 2013;Cao et al, 2014;Hale et al, 2014Hale et al, , 2015Keune et al, 2015;Silk et al, 2015), we could postulate that the asymmetric expression of neurodevelopmental genes might be at the origin of structural and functional changes in this disorder.…”

“…From a neuroimaging viewpoint, compelling evidence points to rather large-scale abnormalities in network organization in ADHD (Sergeant et al, 2006;Konrad and Eickhoff, 2010;Cao et al, 2013), affecting both functional (Cocchi et al, 2012;Colby et al, 2012;Fair et al, 2012;Tomasi and Volkow, 2012;Cao et al, 2013;Di Martino et al, 2013) and structural (Cao et al, 2013;Hong et al, 2014) connectivity. Moreover, an abnormal hemispheric asymmetry of brain structure and function was also consistently reported in ADHD (Dennis and Thompson, 2013;Shang et al, 2013;Cao et al, 2014;Hale et al, 2014Hale et al, , 2015Keune et al, 2015;Silk et al, 2015), suggesting a possible neurodevelopmental scenario for this disorder.…”

“…In terms of neural networks, whole brain resting-state functional imaging studies have reported abnormalities in the well-known Default Mode Network (DMN) (Sonuga-Barke and Castellanos, 2007;Castellanos et al, 2008;Fair et al, 2010;Tomasi and Volkow, 2012;Di Martino et al, 2013;Hale et al, 2014), a "task-negative" network including cortical areas that show temporally-coherent activity during the resting condition (i.e., posterior cingulate cortex (PCC), retrosplenial cortex, inferior parietal lobule, lateral temporal cortex, medial prefrontal cortex and hippocampal formation) (Buckner et al, 2008). These abnormalities included a decreased DMN functional activation (Hale et al, 2014), a delayed DMN maturation (Fair et al, 2010) and a structural/functional right-biased DMN asymmetry (Hale et al, 2014).…”

The Effects of Neurofeedback in the Default Mode Network: Pilot Study Results of Medicated Children with ADHD

“…The main behavioral symptoms of the disorder are inattention and hyperactivity= impulsivity (Diagnostic and Statistical Manual of Mental Disorders [4th ed., text rev. ]; American Psychiatric Association, 2000), but there is increased recognition of a reward=motivation deficit too (Tomasi & Volkow, 2012). According to Konrad and Eickhoff (2010), there has been a shift of focus from regional brain pathology in children with ADHD to dysfunction in distributed network organization.…”