An Oscillatory Mechanism for Multi-level Storage in Short-term Memory

Abstract

Oscillatory activity is commonly observed during the maintenance of information in short-term memory, but its role remains unclear. Non-oscillatory models of short-term memory storage are able to encode stimulus identity through their spatial patterns of activity, but are typically limited to either an all-or-none representation of stimulus amplitude or exhibit a biologically implausible exact-tuning condition. Here, we demonstrate a simple phase-locking mechanism by which oscillatory input enables a circuit to generate persistent or sequential activity patterns that encode information not only in their location but also in a discrete set of amplitudes.

Robustly encoding certainty in a metastable neural circuit model

“…Single neuron models with bistable dendritic compartments can similarly obtain robust and quantized firing rate sets for short term memory [51]. Recent complementary work has suggested strong and sustained oscillatory input may work similarly [52], providing "staircase" shaped transfer functions in phase-locked states with graded firing rate amplitudes. Alternatively, models with clustered microstructure also produce discretely graded population level firing rates when viewed at macroscale (See Fig.…”

“…We analyze a neural circuit model whose inputfiring rate relationships are staircase shaped, reflecting metastable dynamics observed and derived in a number of prior models [33, 34, 51, 52, 56]. Metastability is conceived as arising from successive activation of neural microclusters with increasing cue salience (Fig.…”