title: [Absolute power of cortical oscillations and their topographical distribution in a sample of young adults during resting wakefulness and unspecific attention].
abstract: BACKGROUND
  The EEG records neuronal membrane potential oscillations that depend on the morpho-functional characteristics of the membrane and of modifications by postsynaptic excitatory (PSEP) and inhibitory (PSIP) potentials. The quantitative EEG (qEEG) measures the absolute power (AP) of oscillations separated in frequencies, resulting from the interaction among subcortical-cortical-subcortical ensembles. The hypothesis is that neuronal networks function at a given frequency and that their APs are codes that, by becoming synchronized in diverse ensembles, generate behavior.
  
  
  OBJECTIVE
  To establish the spectral power of cortical oscillations under diverse study paradigms and in different populations. In particular, to identify the AP and topographical distribution of four cerebral frequency bands under resting wakefulness and activation, and to integrate results into a database to establish comparison standards.
  
  
  METHODS
  Undergraduate students, average age of 20.6 +/- 2.6 years, who participated voluntarily in the study. Recordings were made with a Nicolet EEG. We chose, in the first stage, closed eyes (CE) three samples of 12 s each. In the second stage, we chose pairs of 6 s samples, first with CE and then with OE. For their analysis, we applied the Welch periodogram and we plotted the average AP (AAP) and standard deviation (SD) of delta, theta, alpha, and beta per lead. Differences were compared through non-parametric tests (Wilcoxon and Dunnett T3); setting statistical significance at a = 0.05.
  
  
  RESULTS
  Average APs of each frequency band differ significantly in intensity and topographic distribution generating a profile of each rhythm. When opening the eyes, rhythms desynchronized significantly at different intensities in the diverse leads, except for beta in the left fronto-frontal lead.
  
  
  CONCLUSIONS
  Results indicate the existence of cortical ensembles that synchronize at a determined frequency and are modified by visual stimulation, indicating the effects of the subcortico-cortical circuits. The integrated database provides comparison standards to support diagnoses and treatments.
authors.affiliation: Dirección de Investigación, Universidad Nacional Autónoma de Mexico. hbrust@inr.gob.mx
authors.forename: Héctor
authors.initials: H
authors.lastname: Brust-Carmona
authors.forename: Gabriel
authors.initials: G
authors.lastname: Valadez
authors.forename: Blanca
authors.initials: B
authors.lastname: Flores-Avalos
authors.forename: José Antonio
authors.initials: JA
authors.lastname: Martínez
authors.forename: Ana
authors.initials: A
authors.lastname: Sánchez
authors.forename: Miguel Angel
authors.initials: MA
authors.lastname: Rodríguez
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Peñaloza
authors.forename: Oscar
authors.initials: O
authors.lastname: Yáñez
mesh_terms: D000293:Adolescent; D001288:Attention / Q000502:physiology*; D058256:Brain Waves / Q000502:physiology*; D002540:Cerebral Cortex / Q000502:physiology*; D003344:Cortical Synchronization / Q000502:physiology; D003430:Cross-Sectional Studies; D004292:Dominance, Cerebral / Q000502:physiology; D004569:Electroencephalography; D019706:Excitatory Postsynaptic Potentials / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008564:Membrane Potentials / Q000502:physiology; D009415:Nerve Net / Q000502:physiology*; D010775:Photic Stimulation; D014851:Wakefulness / Q000502:physiology*; D055815:Young Adult