A New Hypothesis for Sleep: Tuning for Criticality

Source: https://www.maths.tcd.ie/report_series/abstracts/tcdm0603.html Parent: https://www.maths.tcd.ie/research/papers/

A New Hypothesis for Sleep: Tuning for Criticality

We propose that the critical function of sleep is to prevent uncontrolled neuronal feedback while allowing rapid responses and prolonged retention of short-term memories. \ The goal of learning is optimal behavior, and this sometimes requires the integration of sensory stimuli that are widely separated in time. \ At a neuronal level, this corresponds to persistent activity in local networks. \ Unfortunately, when a network exhibits persistent activity, small changes in the parameters or conditions can lead to runaway oscillations. \ Thus, the very changes that improve the processing performance of the network can put it at risk of runaway oscillation. \ To prevent this, stimulus-dependent plasticity should only be permitted when there is a margin of safety around the current network parameters. \ We propose that a critical role of sleep is to establish a margin of safety by exposing the network to a variety of conditions and inputs, observing for erratic behavior, and -adjusting the parameters accordingly. \ During wakefulness this margin of safety is gradually consumed, ultimately requiring refreshment by another period of sleep. \ When sleep is not possible, an emergency mechanism comes into play to prevent runaway oscillations; \ this is done at the expense of processing efficiency, and constitutes tiredness. \ We contend that this theory matches the phenomenology of sleep and tiredness. \ It also makes a number of novel testable predictions. \