# Treatise on an alternative perspective on the two-process model of sleep regulation

## TL;DR

This paper explores an alternative version of the two-process model of sleep regulation that could better integrate REM sleep and address unresolved issues.

## Contribution

The paper introduces a novel conceptual framework where two sleep-wake processes are more balanced, potentially improving the model's explanatory power.

## Key findings

- The alternative model allows REM sleep to be integrated as a key circadian component.
- It can model four major aspects of the daily sleep-wake cycle more effectively.
- The alternative does not conflict with most existing experimental findings.

## Abstract

The two-process model of sleep regulation, groundbreaking for the field of sleep research, describes sleep-wake behavior as regulated by the interaction of a homeostatic sleep-wake drive, process S (‘sleep debt’), and a circadian pacemaker process C, that “gates” S between two thresholds. The model has achieved great acceptance and application. The conception of the model would have been fundamentally different if one of the model’s creators (Borbély) had retained an alternative conceptual perspective, which he initially described at the time but did not elaborate on. The alternative considers the interaction of two sleep-wake processes more or less equivalent in strength and would a) allow the integration of REM sleep as an important circadian model constituent, b) adequately model four major aspects of the 24-h time course of sleep propensity, c) address some unresolved problems with the current model, and d) not conflict with the vast majority of published experimental research.