Storage of 7 ± 2 Short-Term Memories in Oscillatory Subcycles

TLDR

Psychophysical measurements show humans can hold about seven short‑term memories, and physiological studies suggest these memories are encoded by neuronal activity patterns. The study demonstrates that multiple memories can be stored in a single neural network using nested oscillations, with each memory encoded in a distinct high‑frequency subcycle of a low‑frequency rhythm, and that these patterns repeat on each low‑frequency cycle via activity‑dependent changes in membrane excitability, indicating that brain oscillations serve as a timing mechanism for serial short‑term memory processing.

Abstract

Psychophysical measurements indicate that human subjects can store approximately seven short-term memories. Physiological studies suggest that short-term memories are stored by patterns of neuronal activity. Here it is shown that activity patterns associated with multiple memories can be stored in a single neural network that exhibits nested oscillations similar to those recorded from the brain. Each memory is stored in a different high-frequency ("40 hertz") subcycle of a low-frequency oscillation. Memory patterns repeat on each low-frequency (5 to 12 hertz) oscillation, a repetition that relies on activity-dependent changes in membrane excitability rather than reverberatory circuits. This work suggests that brain oscillations are a timing mechanism for controlling the serial processing of short-term memories.