Biology subjects

Power, S. D.

Publications and source records attributed to Power, S. D..

4 recordsLinked to original sources

bioRxiv2026

Infantile amnesia results from differential memory retrieval in humans

Infantile amnesia, the inability to recall memories from our earliest years, is the most common form of forgetting in mammals. Whether early memories never form, decay, or persist but become inaccessible remains unknown. Here, we investigated the nature of forgetting during the infantile amnesia period by longitudinally testing toddlers aged 18-24 months across the complete memory cycle from encoding, initial retrieval one day later, and delayed retrieval up to six months later, in a novel naturalistic episodic memory paradigm. Computational modelling revealed that forgetting during the infantile amnesia period was heterogeneous. Toddlers were as likely to retain the full memory as to lose it completely, while nearly a quarter retained only part of the memory. Encoding accuracy predicted which toddlers retained the full memory at the test one day later, but not at the delayed test up to six months on. Instead, a retrieval-specific EEG signature predicted complete, but not partial, memory retrieval, distinguishing which toddlers had retained the full memory before their behavioural response. Finally, leveraging the COVID-19 pandemic as a natural experiment, we found that maternal immune activation during pregnancy, as in rodents, alters vulnerability to infantile forgetting in humans. Together, these findings show that early memories formed during the infantile amnesia period are not simply erased but persist in an increasingly inaccessible form, a transformation whose trajectory can be shaped by both the neural retrieval mechanism and the prenatal environment.

neuroscience↗

bioRxiv2026

Capturing the developing brain in motion: A practical tutorial for recording mobile EEG in naturally moving children

This tutorial seeks to facilitate the use of mobile electroencephalography (EEG) in young children. Mobile EEG allows researchers to investigate neural correlates of behavioral and cognitive processes in ecologically valid settings. While mobile EEG has been widely adopted in adult research, studies applying it to freely moving children remain scarce. However, investigating neural processes during active behavior and in interaction with movement is indispensable for advancing our understanding of neural correlates of cognitive development in early childhood. Here, we provide a practical tutorial on the collection and preprocessing of mobile EEG data from children. Drawing on experience and data from a large-scale study with toddlers, we summarize key methodological considerations, discuss common challenges and practical recommendations, and present a preprocessing pipeline developed for developmental mobile EEG data. In addition, we provide example EEG datasets from naturally moving 18-20-month-old toddlers. We argue that incorporating mobile EEG into developmental cognitive neuroscience allows researchers to (i) investigate cognitive development in naturalistic environments, (ii) examine associations among bodily movement, neural activity, and behavior, and (iii) study samples that are difficult to reach with stationary research. HighlightsO_LIMobile EEG enables investigation of neural processes during active behavior C_LIO_LIMobile EEG in moving freely children comes with unique methodological challenges C_LIO_LIWe provide practical recommendations for developmental mobile EEG studies C_LIO_LIA dataset and preprocessing pipeline from a toddler mobile EEG study are provided C_LI

neuroscience↗

bioRxiv2025

Microglial plasticity across development mediates infantile amnesia

Infantile amnesia, the inability to recall episodic memories formed during early childhood, is a hallmark of postnatal brain development. Yet the underlying mechanisms remain poorly understood. This work aimed to gain a better mechanistic understanding of infantile amnesia. Microglia, specialized macrophages of the central nervous system, are known to play an important role in synaptic refinement during postnatal development and have recently been implicated in memory related functions. Here, we identified microglia as key regulators of memory accessibility in infancy. We profiled dynamic changes in microglial morphology across the postnatal window that parallelled the onset of infantile forgetting. We found that pharmacological inhibition of microglial activity during a specific postnatal window prevents infantile amnesia for a contextual fear memory, implicating microglia as active modulators of infant memory persistence. Using activity-dependent tagging of infant encoded engram cells, we demonstrated that microglial inhibition alters engram size and engram reactivation in the amygdala and results in changes in microglia-engram cell interactions. Furthermore, we characterized a relationship between microglial dysfunction and the lack of infantile amnesia in maternal immune activation offspring. Together, these findings reveal a novel role for microglia in regulating infant memory retrieval and suggest that microglial dysfunction may contribute to altered memory trajectories in neurodevelopmental disorders.

neuroscience↗

bioRxiv2022

Immune activation state modulates retrieval of infant engrams

Infantile amnesia is possibly the most ubiquitous form of memory loss in mammals. Despite its widespread relevance, little is known about the biological conditions for infantile amnesia to occur and its effect on the engram cells that encode a memory. We investigated how memories are stored in the brain throughout development by integrating engram labeling technology with mouse models of infantile amnesia. Here, we discovered a phenomenon in which male offspring in maternal immune activation models of autism spectrum disorder do not experience infantile amnesia. We rescued the same apparently forgotten infantile memories in mice by optogenetically reactivating dentate gyrus engram cells labeled during complex infant development experiences. Further, we were able to permanently reinstate lost infantile memories by artificially updating the memory engram, demonstrating that infantile amnesia is a reversible process. Our findings suggest that immune activation during development modulates innate, and reversible, forgetting switches that determine whether infantile amnesia will occur.

neuroscience↗