Amygdala structure and function and its associations with social-emotional outcomes in a low-risk preterm sample.

Amygdala atypical volume development and functional connectivity (FC) at small gestational ages (GA) have been found across childhood. This adult-oriented study assesses whether altered amygdala structure and function is present following low-risk preterm birth. T1-weighted and resting-state functional MRI images of 33 low-risk preterm (30-36 weeks' GA) and 29 full-term (37-42 weeks' GA) young adults of both sexes, aged between 20 and 32 years old, were analyzed using FreeSurfer (v6.0.0) and Coon Toolbox (v21.a). The social-emotional assessment included Happé's Strange Stories Test, the Moral Judgment Test, Delay-Discounting Test, Adult Self Report, and Emotion Regulation Questionnaire. No differences were found in social-emotional outcomes or amygdala volumes between the groups. Low-risk preterm young adults showed increased FC between the left amygdala, right amygdala and medial frontal cortex (MedFC) (F = 9.89, p-FWE = 0.009) at cluster level compared to their full-term peers. However, significant results at connection level were not observed between left and right amygdala. Lastly, increased FC at cluster level between the right amygdala and MedFC, and left amygdala and MedFC, was related to better social-emotional outcomes only in low-risk preterm young adults (F = 6.60, p-FWE = 0.036) at cluster level. At connection level, in contrast, only right amygdala-MedFC increased FC was significantly associated with better social-emotional outcomes. This study reveals that low-risk prematurity does not have an effect on social-emotional outcomes or structural amygdala volumes during young adulthood. However, individuals who were considered to be at a lower risk of exhibiting neurodevelopmental alterations following preterm birth demonstrated increased FC between the left and right amygdala and MedFC.

Long-term brain structural and cognitive outcomes in a low-risk preterm-born sample.

Prematurity has been related to altered brain structure and cognition, and so our aim was to describe them in the absence of major structural brain injury following low-risk preterm birth during adolescence and young adulthood. The sample consisted of 250 participants, 132 of whom were low-risk preterm (30-36 weeks' gestational age) and 118 were full-term individuals (37-42 weeks' gestational age), aged between 16 and 38 years old. All participants underwent an extensive neuropsychological assessment. T1- and diffusion-weighted MRI images of 33 low-risk preterm and 31 full-term young adults (20-32 years old) were analyzed. No differences were found in terms of general cognitive functioning score or current socioeconomic status; however, the low-risk preterm group obtained lower scores in phonetic and semantic fluencies, and theory of mind. Significant reductions were identified in the thalamus volume as well as thicker cortex in the inferior temporal gyrus in the low-risk preterm group. Low-risk preterm young adults evidenced greater regional AD and MD compared to the full-term sample; while low-risk preterm group showed lower mean NDI and ODI (FWE-corrected, p < 0.05). Being born preterm is associated with poorer performance in various cognitive domains (i.e., phonetic and semantic fluencies, and theory of mind) later in life, along with differences in normative structural brain development in inferior temporal gyrus and regional white matter microstructure.

Hippocampal volumes and cognitive performance in children born extremely preterm with and without low-grade intraventricular haemorrhage.

Children born extremely preterm, especially those with intraventricular haemorrhage (IVH), are at increased risk of adverse cognitive outcomes during childhood. The present study aimed to explore the effects of IVH (grades I-II) on hippocampal volumes, and their correlates with cognitive performance. The sample consisted of 94 participants, including 54 children born extremely preterm (19 with IVH, grades I-II), and 40 children born at term. All participants underwent a magnetic resonance imaging study at the age of 10 (Mage = 10.20 years; SDage = 0.78), and 74 of them (45 extremely preterm and 29 full-term) carried out a cognitive assessment at 12 years old. Children born extremely preterm had lower scores in cognitive performance compared to their full-term peers. Significant positive partial correlations were observed between global bilateral hippocampus, left CA-field, and left subiculum volumes with processing speed in the full-term group, while no significant correlations were found in the extremely preterm group. Moderation analyses in the extremely preterm sample revealed that low-grade IVH moderated the relationship between right hippocampal volume and full-IQ (F(4,40) = 5.42, p = 0.001, R2 = 0.35). Having greater right hippocampal volume had a protective effect on full-IQ in those children born extremely preterm with low-grade IVH.