Title
The laminar profile of sleep spindles in humans
Abstract
Sleep spindles are functionally important NREM sleep EEG oscillations which are generated in thalamocortical, corticothalamic and possibly cortico-cortical circuits. Previous hypotheses suggested that slow and fast spindles or spindles with various spatial extent may be generated in different circuits with various cortical laminar innervation patterns. We used NREM sleep EEG data recorded from four human epileptic patients undergoing presurgical electrophysiological monitoring with subdural electrocorticographic grids (ECoG) and implanted laminar microelectrodes penetrating the cortex (IME). The position of IMEs within cortical layers was confirmed using postsurgical histological reconstructions. Many spindles detected on the IME occurred only in one layer and were absent from the ECoG, but with increasing amplitude simultaneous detection in other layers and on the ECoG became more likely. ECoG spindles were in contrast usually accompanied by IME spindles. Neither IME nor ECoG spindle cortical profiles were strongly associated with sleep spindle frequency or globality. Multiple-unit and single-unit activity during spindles, however, was heterogeneous across spindle types, but also across layers and patients. Our results indicate that extremely local spindles may occur in any cortical layer, but co-occurrence at other locations becomes likelier with increasing amplitude and the relatively large spindles detected on ECoG channels have a stereotypical laminar profile. We found no compelling evidence that different spindle types are associated with different laminar profiles, suggesting that they are generated in cortical and thalamic circuits with similar cortical innervation patterns. Local neuronal activity is a stronger candidate mechanism for driving functional differences between spindles subtypes.
Year
DOI
Venue
2021
10.1016/j.neuroimage.2020.117587
NeuroImage
DocType
Volume
ISSN
Journal
226
1053-8119
Citations 
PageRank 
References 
0
0.34
1
Authors
10
Name
Order
Citations
PageRank
Péter P. Ujma100.68
Boglarka Hajnal200.34
Róbert Bódizs300.68
Ferenc Gombos401.01
Lorand Eross500.34
Lucia Wittner600.34
Eric Halgren744234.59
Sydney S. Cash82010.14
Istvan Ulbert9467.28
Daniel Fabo1001.01