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Regional slow waves and spindles in human sleep
Yuval Nir1, Richard J Staba, Thomas Andrillon
1Department of Psychiatry, University of Wisconsin-Madison, Madison, WI 53719, USA.
Neuron
|April 13, 2011
Summary
Most sleep slow waves and neuronal activity are local brain phenomena, not global. This suggests limited intracerebral communication during sleep due to out-of-phase brain oscillations.
Area of Science:
- Neuroscience
- Sleep Science
- Computational Neuroscience
Background:
- Slow waves (<1 Hz) are prominent EEG events in sleep, reflecting cortical neuronal oscillations between active (up) and inactive (down) states.
- The spatial extent of these slow oscillations—whether global or local—remains largely unknown.
Purpose of the Study:
- To investigate the synchronicity and spatial distribution of sleep slow waves and neuronal activity across multiple brain regions.
- To determine if sleep oscillations are a global or local phenomenon.
Main Methods:
- Simultaneous recording of scalp EEG, intracerebral EEG, and unit firing in neurosurgical patients.
- Analysis of neuronal firing patterns and EEG oscillations during sleep.
Main Results:
- Most sleep slow waves and underlying neuronal up/down states occur locally, not synchronously across the entire brain.
- Some brain regions can be active while others remain silent, particularly in late sleep.
- Slow waves can propagate, typically from the medial prefrontal cortex to the medial temporal lobe and hippocampus.
- Sleep spindles, another NREM sleep EEG hallmark, are also predominantly local.
Conclusions:
- Sleep slow waves and neuronal activity are primarily local phenomena.
- Intracerebral communication during sleep is constrained by the often out-of-phase occurrence of slow and spindle oscillations in different brain regions.
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