title: Entrainment of Human Alpha Oscillations Selectively Enhances Visual Conjunction Search.
abstract: The functional role of the alpha-rhythm which dominates the human electroencephalogram (EEG) is unclear. It has been related to visual processing, attentional selection and object coherence, respectively. Here we tested the interaction of alpha oscillations of the human brain with visual search tasks that differed in their attentional demands (pre-attentive vs. attentive) and also in the necessity to establish object coherence (conjunction vs. single feature). Between pre- and post-assessment elderly subjects received 20 min/d of repetitive transcranial alternating current stimulation (tACS) over the occipital cortex adjusted to their individual alpha frequency over five consecutive days. Compared to sham the entrained alpha oscillations led to a selective, set size independent improvement in the conjunction search task performance but not in the easy or in the hard feature search task. These findings suggest that cortical alpha oscillations play a specific role in establishing object coherence through suppression of distracting objects.
authors.affiliation: Neuroprotection Group, German Centre for Neurodegenerative Diseases (DZNE), Magdeburg, Germany.|Clinic for Neurology, Otto von Guericke University, Magdeburg, Germany.
authors.forename: Notger G
authors.initials: NG
authors.lastname: Müller
authors.affiliation: Neuroprotection Group, German Centre for Neurodegenerative Diseases (DZNE), Magdeburg, Germany.
authors.forename: Anne-Katrin
authors.initials: AK
authors.lastname: Vellage
authors.affiliation: Clinic for Neurology, Otto von Guericke University, Magdeburg, Germany.
authors.forename: Hans-Jochen
authors.initials: HJ
authors.lastname: Heinze
authors.affiliation: Clinic for Neurology, Otto von Guericke University, Magdeburg, Germany.
authors.forename: Tino
authors.initials: T
authors.lastname: Zaehle
mesh_terms: D000368:Aged; D000513:Alpha Rhythm; D001288:Attention; D001921:Brain / Q000502:physiology*; D004569:Electroencephalography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011597:Psychomotor Performance; D014796:Visual Perception