An fMRI investigation of neural activation predicting memory formation in children with fetal alcohol spectrum disorders

Abstract

Prenatal alcohol exposure (PAE) is associated with physical anomalies, growth restriction, and a range of neurobehavioral deficits. Although declarative memory impairment has been documented extensively in individuals with fetal alcohol spectrum disorders (FASD), this cognitive process has been examined in only one functional magnetic resonance imaging (fMRI) study, and mechanisms underlying this impairment are not well understood. We used an event-related fMRI design to examine neural activations during visual scene encoding that predict subsequent scene memory in 51 right-handed children (age range = 10–14 years, M = 11.3, SD = 1.3) whose mothers had been recruited and interviewed prospectively about their alcohol use during pregnancy. Following examination by expert dysmorphologists, children were assigned to one of three FASD diagnostic groups: FAS/PFAS (nFAS = 7; nPFAS = 4), nonsyndromal heavily exposed (HE; n = 14), and Controls (n = 26). Subsequent memory was assessed in a post-scan recognition test, and subsequent memory activations were examined by contrasting activations during encoding of scenes that were subsequently remembered (hits) to those for incorrectly judged as ‘new’ (misses). Recognition accuracy did not differ between groups. Pooled across groups, we observed extensive bilateral subsequent memory effects in regions including the hippocampal formation, posterior parietal cortex, and occipital cortex—a pattern consistent with previous similar studies of typically developing children. Critically, in the group of children with FAS or PFAS, we observed activations in several additional regions compared to HE and Control groups. Given the absence of between-group differences in recognition accuracy, these data suggest that in achieving similar memory compared to children in the HE and Control groups, children with FAS and PFAS recruit more extensive neural resources to achieve successful memory formation.

Keywords

• Fetal alcohol spectrum disorders
• Prenatal alcohol exposure
• fMRI
• Memory encoding
• Memory formation
• Subsequent memory formation