Altered hippocampal microstructure and function in children who experienced Hurricane Irma

Abstract

Hurricane Irma was the most powerful Atlantic hurricane in recorded history, displacing 6 million and killing over 120 people in the state of Florida alone. Unpredictable disasters like Irma are associated with poor cognitive and health outcomes that can disproportionately impact children. This study examined the effects of Hurricane Irma on the hippocampus and memory processes previously related to unpredictable stress. We used an innovative application of an advanced diffusion‐weighted imaging technique, restriction spectrum imaging (RSI), to characterize hippocampal microstructure (i.e., cell density) in 9‐ to 10‐year‐old children who were exposed to Hurricane Irma relative to a non‐exposed control group (i.e., assessed the year before Hurricane Irma). We tested the hypotheses that the experience of Hurricane Irma would be associated with decreases in: (a) hippocampal cellularity (e.g., neurogenesis), based on known associations between unpredictable stress and hippocampal alterations; and (b) hippocampal‐related memory function as indexed by delayed recall. We show an association between decreased hippocampal cellularity and delayed recall memory in children who experienced Hurricane Irma relative to those who did not. These findings suggest an important role of RSI for assessing subtle microstructural changes related to functionally significant changes in the developing brain in response to environmental events.

Air pollution from biomass burning disrupts early adolescent cortical microarchitecture development

“…We chose to assess how one-year average exposure to PM 2.5 sources during childhood (i.e., between ages 8 and 10 years) were related to changes in cortical microarchitecture between ages 9 and 13 years. Cortical microstructure was estimated from both anisotropic and isotropic intracellular diffusion, reflecting neurite density and cellularity, respectively (Carper et al, 2017; Conley et al, 2021; Newman et al, 2023; Palmer et al, 2022; Rapuano et al, 2020), as hypothesized neurotoxic effects of PM 2.5 likely include disruption to ongoing synaptic refinement during adolescence and altered cellularity due to neuron death and/or reactive gliosis. Using Partial Least Squares Correlation (PLSC), we jointly modeled latent dimensions of association between source-specific exposure to PM 2.5 and changes in cortical microarchitecture.…”