Introduction: Recent topographic analyses of sigma EEG activity dur-ing NREM sleep pointed to the existence of two distinct sleep spindle(SS) types: “slow” spindles at ~12 Hz more pronounced over the frontalsites, and “fast” SS at ~14 Hz more pronounced over centro-parietalsites; the former declining and the latter increasing over consecutivesleep episodes. Functional dissociations have also been reported, as afunction of age and maturation, homeostatic and circadian factors, men-strual cycle phase, pregnancy and pharmacological agents. These resultshave been interpreted according to two functionally separated spindlegenerators.On the other hand, lower and higher frequencies of SS havebeen attributed to a single mechanism, namely, the duration of hyperpo-larization-rebound sequence in thalamocortical neurons; and corticalareas on which “slow” SS have been detected are related to those thala-mic nuclei in which relay cells display long hyperpolarizations.In fact,most studies showing the two cortically-independent SS bulk the boundsof sigma band from the traditional 12-14 Hz range, including frequencybins traditionally considered within the alpha band. Secondly, there aregreat inter-individual differences, and topographical analyses onbetween-subject averaged data could confound individual (different)cortical topographical distributions with the existence of different topo-graphically-specific SS. Finally, spindle frequency could change as afunction of the same variables differently affecting the two types of SS.Topographical EEG analysis in single subjects could allow to disentan-gle the question.Methods: Data from sleep recordings (Fz-A1, Cz-A1, Pz-A1, Oz-A1) of10 normal males served as database. The subjects participated in a SWSdeprivation study (six consecutive nights). Power values were calculat-ed across a 8.00-15.50 Hz range in a 0.25-Hz resolution for NREMepisodes of each subject. Absolute power was transformed into z scores.Results: Four subjects had one spectral peak in the range of SS fre-quencies on all derivations (12.25-13.25 Hz); three others had two spec-tral peaks on different derivations, with one peak higher on Fz (10.25-11.25 Hz) and another peak higher on Cz-Pz (13.50-13.75 Hz); the lastthree subjects had two spectral peaks discernible only on Fz (respective-ly at 10.00-10.50 and 12.50-13.00 Hz).Conclusions: Individual data show one kind of SS, ranging within the12.25-13.75 Hz, and in some subjects alpha activity peaking on moreanterior brain sites. However, the most impressive result is the highspectral invariancy of individual antero-posterior topography in the8.00-15.50 Hz frequency range, notwithstanding wide changes in sleeparchitecture across the six nights (one adaptation, two baselines, twonights without SWS, one recovery). This invariancy of EEG topographymay be related to brain anatomy, and studies comparing monozygoticand dizygotic twins will allow to demonstrate this hypothesi (12) (PDF) An individual fingerprint of human NREM sleep: The antero-posterior topography of the middle EEG frequencies. Available from: https://www.researchgate.net/publication/295776287_An_individual_fingerprint_of_human_NREM_sleep_The_antero-posterior_topography_of_the_middle_EEG_frequencies

An individual fingerprint of human NREM sleep: The antero-posterior topography of the middle EEG frequencies / De Gennaro, L; Ferrara, M; Curcio, G; Cristiani, R; Bertini, M. - In: SLEEP. - ISSN 1550-9109. - (2003). (Intervento presentato al convegno APSS Annual Meeting Denver tenutosi a Chicago).

An individual fingerprint of human NREM sleep: The antero-posterior topography of the middle EEG frequencies

De Gennaro, L;Cristiani, R;
2003

Abstract

Introduction: Recent topographic analyses of sigma EEG activity dur-ing NREM sleep pointed to the existence of two distinct sleep spindle(SS) types: “slow” spindles at ~12 Hz more pronounced over the frontalsites, and “fast” SS at ~14 Hz more pronounced over centro-parietalsites; the former declining and the latter increasing over consecutivesleep episodes. Functional dissociations have also been reported, as afunction of age and maturation, homeostatic and circadian factors, men-strual cycle phase, pregnancy and pharmacological agents. These resultshave been interpreted according to two functionally separated spindlegenerators.On the other hand, lower and higher frequencies of SS havebeen attributed to a single mechanism, namely, the duration of hyperpo-larization-rebound sequence in thalamocortical neurons; and corticalareas on which “slow” SS have been detected are related to those thala-mic nuclei in which relay cells display long hyperpolarizations.In fact,most studies showing the two cortically-independent SS bulk the boundsof sigma band from the traditional 12-14 Hz range, including frequencybins traditionally considered within the alpha band. Secondly, there aregreat inter-individual differences, and topographical analyses onbetween-subject averaged data could confound individual (different)cortical topographical distributions with the existence of different topo-graphically-specific SS. Finally, spindle frequency could change as afunction of the same variables differently affecting the two types of SS.Topographical EEG analysis in single subjects could allow to disentan-gle the question.Methods: Data from sleep recordings (Fz-A1, Cz-A1, Pz-A1, Oz-A1) of10 normal males served as database. The subjects participated in a SWSdeprivation study (six consecutive nights). Power values were calculat-ed across a 8.00-15.50 Hz range in a 0.25-Hz resolution for NREMepisodes of each subject. Absolute power was transformed into z scores.Results: Four subjects had one spectral peak in the range of SS fre-quencies on all derivations (12.25-13.25 Hz); three others had two spec-tral peaks on different derivations, with one peak higher on Fz (10.25-11.25 Hz) and another peak higher on Cz-Pz (13.50-13.75 Hz); the lastthree subjects had two spectral peaks discernible only on Fz (respective-ly at 10.00-10.50 and 12.50-13.00 Hz).Conclusions: Individual data show one kind of SS, ranging within the12.25-13.75 Hz, and in some subjects alpha activity peaking on moreanterior brain sites. However, the most impressive result is the highspectral invariancy of individual antero-posterior topography in the8.00-15.50 Hz frequency range, notwithstanding wide changes in sleeparchitecture across the six nights (one adaptation, two baselines, twonights without SWS, one recovery). This invariancy of EEG topographymay be related to brain anatomy, and studies comparing monozygoticand dizygotic twins will allow to demonstrate this hypothesi (12) (PDF) An individual fingerprint of human NREM sleep: The antero-posterior topography of the middle EEG frequencies. Available from: https://www.researchgate.net/publication/295776287_An_individual_fingerprint_of_human_NREM_sleep_The_antero-posterior_topography_of_the_middle_EEG_frequencies
2003
APSS Annual Meeting Denver
sleep; EEG; genetics; cortical topography
04 Pubblicazione in atti di convegno::04c Atto di convegno in rivista
An individual fingerprint of human NREM sleep: The antero-posterior topography of the middle EEG frequencies / De Gennaro, L; Ferrara, M; Curcio, G; Cristiani, R; Bertini, M. - In: SLEEP. - ISSN 1550-9109. - (2003). (Intervento presentato al convegno APSS Annual Meeting Denver tenutosi a Chicago).
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/1709778
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