Early life adversity and borderline intellectual functioning negatively impact limbic system connectivity in childhood: a connectomics-based study

Abstract

Epigenetic factors related to early life adversity (ELA) in childhood are major risk factors for borderline intellectual functioning (BIF). BIF affects both adaptive and intellectual abilities, commonly leading to school failure and to an increased risk to develop mental and social problems in the adulthood. This study aimed to investigate the neurobiological underpinnings of ELA associated with BIF in terms of global topological organization and structural connectivity and their relation with intellectual functioning. BIF (N=32) and age-matched typical development (TD, N=14) children were evaluated for intelligence quotient (IQ), behavioral competencies, and ELA. Children underwent an anatomical and diffusion-weighted MR imaging (DWI) protocol. Global brain topological organization was assessed measuring segregation and integration indexes. Moreover, structural matrices, measuring normalized number of fibers (NFn), were compared between the 2 groups using network-based statistics. Finally, a linear regression model was used to explore the relationship between network parameters and clinical measures.Results showed increased behavioral difficulties and ELA, together with decreased network integration in BIF children. Moreover, significantly lower NFn was observed in the BIF group (p=.039) in a sub-network comprising anterior and posterior cingulate, the pericallosal sulcus, the orbital frontal areas, amygdala, basal ganglia, the accumbens nucleus, and the hippocampus. Linear regression showed that NFn significantly predicted IQ (p<.0001).This study demonstrated that ELA in children with BIF is associated with a decreased information integration at the global level, and with an altered structural connectivity within the limbic system strictly related to the intellectual functioning.

Intervening on the Developmental Course of Children With Borderline Intellectual Functioning With a Multimodal Intervention: Results From a Randomized Controlled Trial

“…Childhood is indeed a critical period because of the dramatic changes that occur in the brain. It has been demonstrated that low SES correlates with both reduced learning abilities and abnormal brain development in several critical regions including the hippocampus, amygdala, parahippocampal and sensory-motor cortices, and limbic system connectivity (Hanson et al, 2011;Baglio et al, 2014;Hair et al, 2015;Blasi et al, 2019). These data are relevant as they indicate that children with BIF might be at risk of learning difficulties and emotional problems at a very early age.…”