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Increasing stimulus similarity drives nonmonotonic representational change in hippocampus

Citation

Wammes, Jeffrey (2021), Increasing stimulus similarity drives nonmonotonic representational change in hippocampus, Dryad, Dataset, https://doi.org/10.5061/dryad.t4b8gtj38

Abstract

Studies of hippocampal learning have obtained seemingly contradictory results, with manipulations that increase coactivation of memories sometimes leading to differentiation of these memories, but sometimes not. These results could potentially be reconciled using the nonmonotonic plasticity hypothesis, which posits that representational change (memories moving apart or together) is a U-shaped function of the coactivation of these memories during learning. Testing this hypothesis requires manipulating coactivation over a wide enough range to reveal the full U-shape. To accomplish this, we used a novel neural network image synthesis procedure to create pairs of stimuli that varied parametrically in their similarity in high-level visual regions that provide input to the hippocampus. Sequences of these pairs were shown to human participants during high-resolution fMRI. As predicted, learning changed the representations of paired images in the dentate gyrus as a U-shaped function of image similarity, with neural differentiation occurring only for moderately similar images.

Methods

Please refer to the manuscript for methodological information.

Citation: Wammes, Jeffrey D., Kenneth A. Norman, and Nicholas B. Turk-Browne. "Increasing stimulus similarity drives nonmonotonic representational change in hippocampus." eLife.

Usage Notes

Please refer to the README for information about how to use this dataset.

Funding

National Institute of Mental Health, Award: R01 MH069456