Timing of iron deficiency and recognition memory in infancy

• Published in: Nutritional neuroscience 2022-01, Vol.25 (1), p.1-10
• Main Authors: Geng, Fengji, Mai, Xiaoqin, Zhan, Jianying, Xu, Lin, Georgieff, Michael, Shao, Jie, Lozoff, Betsy
• Format: Article
• Language: English
• Subjects: Age Factors; event-related potentials; Evoked Potentials; Facial Recognition - physiology; Female; Ferritins - blood; Fetal Blood - chemistry; fetal-neonatal iron deficiency; Heme - analysis; Humans; Infancy; Infant; Infant, Newborn; Iron - blood; Iron Deficiencies - physiopathology; Iron Deficiencies - psychology; Mothers; postnatal iron deficiency; Pregnancy; Protoporphyrins - blood; recognition memory; Recognition, Psychology - physiology
• ISSN: 1028-415X; 1476-8305
• DOI: 10.1080/1028415X.2019.1704991

Objective: To determine the relationship between iron deficiency (or iron-deficient, ID) and neural correlates of recognition memory depending on ID timing (gestation vs. infancy) and infant age at testing (9 vs. 18 months). Study design: Event-related potentials (ERP) were used in a visual recognition memory task (mother vs. stranger face) to compare healthy term infants according to iron status at birth and 9 months. Fetal-neonatal ID was defined as cord serum ferritin < 75 µg/l or zinc protoporphrin/heme ratio > 118 µmol/mol, postnatal ID as ≥ 2 abnormal iron measures at 9 months with normal cord-blood iron status, and iron-sufficient as not ID at birth or 9 months. Recognition of mother faces was measured by negative component (Nc) and late slow wave (LSW). These ERP components reflect attention and memory updating processes, respectively. Results: All groups showed differences in Nc amplitude elicited by mother and stranger faces at 9 months. At 18 months, only postnatal ID and iron-sufficient groups showed condition differences in Nc amplitude. However, the 2 groups were different in the involved brain regions. For LSW, only the 2 ID groups showed condition differences in amplitude at 9 months. At 18 months, condition differences were not observed in any group. Conclusions: This study indicates that the timing of ID in early life (fetal-neonatal vs. postnatal) modulates the impact of ID on recognition memory. Such impact also varies depending on the age of infants at testing (9 vs. 18 months).