# Neural Substrates of Word Retention and Generalization in Toddlers

> **NIH NIH R01** · UNIVERSITY OF CALIFORNIA AT DAVIS · 2024 · $542,304

## Abstract

PROJECT SUMMARY
Infants and young children amass a vocabulary at a remarkable pace during the first 3 years. The size of
vocabulary, and the rate of its growth predict future outcomes including academic achievement. Research on
vocabulary development has largely focused on the cognitive processes underlying how young children learn
new words, but we know remarkably little about the processes that support young children's retention of words
over long delays to eventually become integrated into their lexicon. The examination of the neural processes
supporting young children's retention will shed new light on contributing processes.
We propose that the hippocampus enables learning and initial retention of the arbitrary association between
words and their referents, but that additional cortical mechanisms in the anterior medial temporal lobe and
medial prefrontal cortex are critical to respectively support longer retention and abstraction of meaning across
multiple exposures. Further, we propose that opportunities to repeat and generalize which present in the child's
environment are particularly likely to engage these cortical mechanisms in young children. Finally, we propose
that neural activations capture processes underlying individual differences in vocabulary development. We
developed novel functional Magnetic Resonance Imaging (fMRI) experimental paradigms that are appropriate
for use in toddlers ages 25 to 35 months, a period during which toddlers learn hundreds of words. We will
leverage targeted memory reactivation occurring during natural nocturnal sleep to elucidate neural
mechanisms contributing to word retention and to predict vocabulary size and growth between 2 and 3 years of
age.
Relevance for Public Health: The acquisition of a vocabulary is critical for communication and understanding,
and its size and growth predict various outcomes, including reading ability. Language acquisition is impaired in
several neurodevelopmental disorders underscoring that a characterization of memory and vocabulary
development is key to understanding adaptive functioning in various populations of children. This research will
contribute to provide a stronger conceptual, empirical, and methodological foundation for examining
populations of children who exhibit altered language development and memory difficulties due to a variety of
conditions (e.g., Autism Spectrum Disorder, Down's Syndrome).

## Key facts

- **NIH application ID:** 10903632
- **Project number:** 1R01HD112686-01A1
- **Recipient organization:** UNIVERSITY OF CALIFORNIA AT DAVIS
- **Principal Investigator:** SIMONA GHETTI
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $542,304
- **Award type:** 1
- **Project period:** 2024-09-01 → 2029-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10903632

## Citation

> US National Institutes of Health, RePORTER application 10903632, Neural Substrates of Word Retention and Generalization in Toddlers (1R01HD112686-01A1). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10903632. Licensed CC0.

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