The relationship between short-term memory capacity and EEG power spectral density

Area of Science:

• Cognitive Neuroscience
• Computational Neuroscience
• Biophysics

Background:

• Short-term memory capacity is a fundamental cognitive limit.
• Cognitive processing speed is influenced by memory capacity.
• Electroencephalography (EEG) measures brain electrical activity and power spectral density.

Purpose of the Study:

• To investigate the relationship between memory span, mental speed, and information entropy.
• To explore the correlation between short-term memory capacity and EEG power spectral density.
• To propose a model for brain information processing analogous to quantum mechanics.

Main Methods:

• Calculating information entropy by multiplying memory span by mental speed.
• Analyzing EEG power spectral density and its relationship with memory metrics.
• Identifying EEG harmonics and their correlation with memory span.
• Examining EEG impulse response eigenvalues and their relation to the P300 component.

Main Results:

• Information entropy of short-term memory capacity was derived and found to be rate-limiting for cognitive functions.
• A direct correspondence was observed between memory capacity metrics and EEG power spectral density.
• The number of EEG harmonics (n=1-9) was found to be identical to memory span.
• EEG impulse response eigenvalues were represented by zero-crossings up to the convolved fundamental (P300).

Conclusions:

• The brain functions as an ideal detector, measuring waveform energy, similar to quantum mechanical systems.
• Brain signal and memory metrics can be conceptualized as a superposition of 'n pi states' with varying energies and eigenvalues.
• This framework provides a unified understanding of cognitive processes and brain activity regardless of stimulus or brain state.