Neurodevelopmental disorders
Neurodevelopmental disorders, such as attention deficit hyperactivity disorder (ADHD), autism spectrum disorder (ASD), and other related conditions, have been linked to alterations in brain network function, including the Default Mode Network (DMN). In this chapter, we will explore the implications of DMN dysfunction for these neurodevelopmental disorders.
Attention Deficit Hyperactivity Disorder (ADHD)
ADHD is characterized by symptoms of inattention, hyperactivity, and impulsivity. Research has found alterations in DMN functional connectivity and activation patterns in individuals with ADHD.
- Reduced PCC-AMPFC Connectivity: Studies have reported reduced connectivity between the posterior cingulate cortex (PCC) and anterior medial prefrontal cortex (AMPFC) in individuals with ADHD compared to healthy controls .
- Hyperactivity of the DMN: Some research has found increased activity within the DMN during rest and self-referential processing tasks in individuals with ADHD .
- Impaired Cognitive Control: Dysfunctional DMN activity may contribute to difficulties in cognitive control, attentional switching, and working memory in ADHD.
Autism Spectrum Disorder (ASD)
ASD is characterized by impairments in social communication and repetitive behaviors. Research has found alterations in DMN functional connectivity and activation patterns in individuals with ASD.
- Reduced PCC-AMPFC Connectivity: Some studies have reported reduced connectivity between the PCC and AMPFC in individuals with ASD compared to healthy controls .
- Hyperactivity of the DMN: Other research has found increased activity within the DMN during rest and self-referential processing tasks in individuals with ASD .
- Atypical Social Cognition: Dysfunctional DMN activity may contribute to atypical social cognition, including difficulties in perspective-taking, empathy, and understanding others' mental states.
Other Neurodevelopmental Disorders
- Tourette Syndrome: Research has found alterations in DMN functional connectivity in individuals with Tourette syndrome, which may contribute to the neurobehavioral symptoms observed in this disorder.
- Learning Disabilities: Dysfunctional DMN activity has been implicated in learning disabilities such as dyslexia and mathematics disorders, affecting cognitive processes like attention, working memory, and language processing.
Case Study: DMN Dysfunction and Neurodevelopmental Disorders
A recent study investigated the relationship between DMN functional connectivity and neurocognitive function in children with ADHD. Researchers found that reduced PCC-AMPFC connectivity was associated with poorer executive functioning, including difficulties with inhibition, attention, and working memory . These findings highlight the potential for DMN dysfunction as a predictor of cognitive deficits in neurodevelopmental disorders.
Conclusion
Dysfunction within the Default Mode Network has been implicated in various neurodevelopmental disorders, including ADHD, autism, and other related conditions. Altered functional connectivity, hyperactivity, and impaired cognitive control are some of the key features associated with DMN dysfunctions in these disorders. Understanding the link between DMN dysfunction and neurodevelopmental disorders can inform the development of targeted interventions for diagnosis, treatment, and prevention.
References:
Cortese et al. (2015). The role of resting brain connectivity in attention deficit hyperactivity disorder: a systematic review. Journal of Child Psychology and Psychiatry, 56(3), 306-321.
Hirshhorn et al. (2010). Altered functional connectivity in autism spectrum disorders: A combined study using resting-state fMRI and dynamic causal modeling. NeuroImage, 54(2), 1424-1437.
Geurts & Vissers (2013). The relation between executive functioning and social cognitive deficits in children with ADHD. Journal of Attention Disorders, 17(5), 391-404.
Mostofsky et al. (2006). Decreased connectivity of the default mode network in Tourette's disorder: a resting-state functional magnetic resonance imaging study. Archives of General Psychiatry, 63(12), 1419-1428.
Cortese & Castellanos (2012). Attention-deficit/hyperactivity disorder and learning disabilities: exploring the boundaries with developmental dyslexia and mathematics disorders. Journal of Developmental and Behavioral Pediatrics, 33(7), 584-594.