A new way to look at sleep : separation & convergence
- Author(s): Low, Philip Steven
- et al.
Despite over 70 years of active research in mammalian EEGs, most of the neural structures responsible for sleep and waking rhythms have yet to be identified. At time of writing, three major beliefs pervade the field of sleep : 1) The neocortex is largely necessary for the production of "mammalian" sleep rhythms; 2) Human REM sleep is "paradoxical" insofar as the oscillations produced during REM sleep are "awake-like"; 3) Human sleep can only be objectively analyzed by human scorer. This way of looking at sleep is in need of major revision, as : 1) Birds, devoid of a neocortex, can produce oscillations which bare great similarity with those observed in mammals, in terms of both their raw signals and ultradian properties; 2) A temporal map of brain activity produced using a single channel of EEG is sufficient to clearly show that REM sleep and Waking have different and separable EEG profiles. Human REM sleep is therefore not paradoxical. 3) Sleep and Waking Stages can in fact be easily identified computationally using a single channel of EEG, obviating the need for human based sleep scoring. Moreover, it appears that low-passing from the skull reflected in EEGs can be easily circumvented, thus providing researchers and clinicians with a non-invasive window into brain activity, with high resolution in both the time and frequency domains. Furthermore, the possibility of there being yet another human sleep state should be fully explored. The use of these and similar techniques will hopefully minimize the significant strain placed on both humans and animals in at least the contexts of medicine as well as basic and clinical research