Attachment security and striatal functional connectivity in typically developing children.

Attachment security is formed through interactions with a main caregiver during the first three years of life and reflects inter-individual differences in mental representations for the relationship. The striatum is known to be a key structure to initiate attachment behaviours and maintain attachment relationships as well as to modulate reward-related processing as part of the approach module in current neurobiological models of human attachment. Although findings have suggested critical roles of the striatum in inter-individual differences in attachment, most studies were based on a wide variety of tasks and very few have investigated these associations in intrinsic brain connectivity in typically developing children. In the present study, using resting-state functional magnetic resonance imaging, we examined the striatal functional connectivity according to children's attachment security in 68 nine-year-olds (Secure attachment = 39, Insecure attachment = 29, mean age/SD = 9.62/0.69). Children with secure attachment demonstrated increased functional connectivity in the tempro-limbic region, compared to children with insecure attachment. In addition, the child-reported attachment security scores were negatively associated with the caudate-prefrontal connectivity, but positively with the putamen-visual area connectivity. These data demonstrate that inter-individual differences in attachment can be captured in striatal functional connectivity organization in the typical brain.

A selective involvement of putamen functional connectivity in youth with internet gaming disorder.

Brain cortico-striatal circuits have consistently been implicated in the pathology of addiction related disorders. We applied a reliable seed-based analysis of the resting-state brain activity to comprehensively delineate the subdivisions of striatal functional connectivity implicated in internet gaming disorder. Among twelve right-handed male adolescents with internet gaming disorder and 11 right-handed and gender-matched healthy controls, we examined group differences in the functional connectivity of dorsal and ventral subdivisions of the caudate nucleus and putamen, as well as the association of these connectivity indices with behavioral measures of internet use. Adolescents with internet gaming disorder showed significantly reduced dorsal putamen functional connectivity with the posterior insula-parietal operculum. More time spent playing online games predicted significantly greater functional connectivity between the dorsal putamen and bilateral primary somatosensory cortices in adolescents with internet gaming disorder, and significantly lower functional connectivity between the dorsal putamen and bilateral sensorimotor cortices in healthy controls. The dorsal putamen functional connectivity was significantly and specifically different in adolescents with internet gaming disorder. The findings suggest a possible biomarker of internet gaming disorder.

Decreased thalamic volumes in adolescent inhalant users from Korea and Australia.

OBJECTIVES: Research investigating the impact of inhalant misuse on brain structure suggests abnormalities in subcortical regions. We investigated the association between inhalant misuse and subcortical brain volumes in adolescents. METHODS: Based on a collaborative dataset from South Korea (inhalant users: N = 15, mean age = 16.7, SD = 1.1; controls: N = 15, mean age = 15.4, SD = 1.2) and Australia (inhalant users: N = 7, mean age = 18.2, SD = 1.4; controls: N = 7, mean age = 18.9, SD = 2.6), the volumes of caudate nucleus, putamen, pallidum, amygdala, hippocampus, and thalamus were estimated in adolescent inhalant users and healthy adolescents using FreeSurfer. RESULTS: The results revealed a significantly decreased right thalamic volume in adolescent inhalant users (P = 0.042), along with a trend-level decrease in left thalamic volume (P = 0.061). A negative correlation (r = -0.544; P = 0.036) between thalamic volume and severity of inhalant use (i.e., reduced volumes associated with greater use) was identified among Korean participants. CONCLUSIONS: These findings suggest that compared with other subcortical structures, the thalamus is particularly sensitive to damage following chronic inhalant exposure during adolescence.

Reduced orbitofrontal cortical thickness in male adolescents with internet addiction.

BACKGROUND: The orbitofrontal cortex (OFC) has consistently been implicated in the pathology of both drug and behavioral addictions. However, no study to date has examined OFC thickness in internet addiction. In the current study, we investigated the existence of differences in cortical thickness of the OFC in adolescents with internet addiction. On the basis of recently proposed theoretical models of addiction, we predicted a reduction of thickness in the OFC of internet addicted individuals. FINDINGS: Participants were 15 male adolescents diagnosed as having internet addiction and 15 male healthy comparison subjects. Brain magnetic resonance images were acquired on a 3T MRI and group differences in cortical thickness were analyzed using FreeSurfer. Our results confirmed that male adolescents with internet addiction have significantly decreased cortical thickness in the right lateral OFC (p<0.05). CONCLUSION: This finding supports the view that the OFC alterations in adolescents with internet addiction reflect a shared neurobiological marker of addiction-related disorders in general.

Decreased functional brain connectivity in adolescents with internet addiction.

BACKGROUND: Internet addiction has become increasingly recognized as a mental disorder, though its neurobiological basis is unknown. This study used functional neuroimaging to investigate whole-brain functional connectivity in adolescents diagnosed with internet addiction. Based on neurobiological changes seen in other addiction related disorders, it was predicted that connectivity disruptions in adolescents with internet addiction would be most prominent in cortico-striatal circuitry. METHODS: Participants were 12 adolescents diagnosed with internet addiction and 11 healthy comparison subjects. Resting-state functional magnetic resonance images were acquired, and group differences in brain functional connectivity were analyzed using the network-based statistic. We also analyzed network topology, testing for between-group differences in key graph-based network measures. RESULTS: Adolescents with internet addiction showed reduced functional connectivity spanning a distributed network. The majority of impaired connections involved cortico-subcortical circuits (∼24% with prefrontal and ∼27% with parietal cortex). Bilateral putamen was the most extensively involved subcortical brain region. No between-group difference was observed in network topological measures, including the clustering coefficient, characteristic path length, or the small-worldness ratio. CONCLUSIONS: Internet addiction is associated with a widespread and significant decrease of functional connectivity in cortico-striatal circuits, in the absence of global changes in brain functional network topology.