title: Imaging cortical activity following affective stimulation with a high temporal and spatial resolution.
abstract: BACKGROUND
  The affective and motivational relevance of a stimulus has a distinct impact on cortical processing, particularly in sensory areas. However, the spatial and temporal dynamics of this affective modulation of brain activities remains unclear. The purpose of the present study was the development of a paradigm to investigate the affective modulation of cortical networks with a high temporal and spatial resolution. We assessed cortical activity with MEG using a visual steady-state paradigm with affective pictures. A combination of a complex demodulation procedure with a minimum norm estimation was applied to assess the temporal variation of the topography of cortical activity.
  
  
  RESULTS
  Statistical permutation analyses of the results of the complex demodulation procedure revealed increased steady-state visual evoked field amplitudes over occipital areas following presentation of affective pictures compared to neutral pictures. This differentiation shifted in the time course from occipital regions to parietal and temporal regions.
  
  
  CONCLUSIONS
  It can be shown that stimulation with affective pictures leads to an enhanced activity in occipital region as compared to neutral pictures. However, the focus of differentiation is not stable over time but shifts into temporal and parietal regions within four seconds of stimulation. Thus, it can be crucial to carefully choose regions of interests and time intervals when analyzing the affective modulation of cortical activity.
authors.affiliation: Department of Psychology, University of Konstanz and Center for Psychiatry Reichenau, Konstanz, Germany. julian.keil@uni-konstanz.de
authors.forename: Julian
authors.initials: J
authors.lastname: Keil
authors.forename: Hannah
authors.initials: H
authors.lastname: Adenauer
authors.forename: Claudia
authors.initials: C
authors.lastname: Catani
authors.forename: Frank
authors.initials: F
authors.lastname: Neuner
mesh_terms: D000328:Adult; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000502:physiology*; D004644:Emotions; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D015225:Magnetoencephalography; D008297:Male; D009483:Neuropsychological Tests; D013997:Time Factors