title: [Temporal spectral evolution of electroencephalogram. Methodology and applications].
abstract: BACKGROUND
  The event related potentials (ERPs) allow to study the evolution of the cerebral electric activity related with the diverse sensorial, motors and cognitive processes. However, the ERPs and the spectral analyses based in Fast Fourier Transform, are not able to show the variations along the time of the spectral content of the electroencephalogram (EEG).
  
  
  OBJECTIVE
  The present work will show the necessary methodology to obtain the temporal dynamics of the frequency (TSE) in the EEG, a technique described by Salmelin and Hari (1994) that allows the analysis of the modulations of any spectral band along the time.
  
  
  METHODS
  The presented data correspond to the electroencephalographic registration of 20 human subjects during an experiment of visual spatial attention.
  
  
  RESULTS
  The modulations of the ERPs differ of the observed by the spectral techniques in latency and topography. Likewise, comparing different spectral techniques is proven that the TSE allows to define with more temporal precision the variations on the spectral content.
  
  
  CONCLUSIONS
  The application of the TSE technique to the same EEG signal that is used for obtaining the ERPs, allows the inclusion of the variable time in the spectral analysis of the EEG, what can be crucial to understand the physiological bases of some neuropathologies.
authors.affiliation: Laboratorio de Psicobiología, Departamento de Psicología Experimental, Facultad de Psicología de la Universidad de Sevilla, Sevilla, 41005, España. marrufo@cica.es
authors.forename: M
authors.initials: M
authors.lastname: Vázquez
authors.forename: E
authors.initials: E
authors.lastname: Vaquero
authors.forename: M J
authors.initials: MJ
authors.lastname: Cardoso
authors.forename: C M
authors.initials: CM
authors.lastname: Gómez
mesh_terms: D000293:Adolescent; D000328:Adult; D001288:Attention; D004569:Electroencephalography; D005071:Evoked Potentials / Q000502:physiology*; D005583:Fourier Analysis; D006801:Humans; D013997:Time Factors; D014796:Visual Perception / Q000502:physiology