title: Real-time MEG neurofeedback training of posterior alpha activity modulates subsequent visual detection performance.
abstract: It has been demonstrated that alpha activity is lateralized when attention is directed to the left or right visual hemifield. We investigated whether real-time neurofeedback training of the alpha lateralization enhances participants' ability to modulate posterior alpha lateralization and causes subsequent short-term changes in visual detection performance. The experiment consisted of three phases: (i) pre-training assessment, (ii) neurofeedback phase and (iii) post-training assessment. In the pre- and post-training phases we measured the threshold to covertly detect a cued faint Gabor stimulus presented in the left or right hemifield. During magnetoencephalography (MEG) neurofeedback, two face stimuli superimposed with noise were presented bilaterally. Participants were cued to attend to one of the hemifields. The transparency of the superimposed noise and thus the visibility of the stimuli were varied according to the momentary degree of hemispheric alpha lateralization. In a double-blind procedure half of the participants were provided with sham feedback. We found that hemispheric alpha lateralization increased with the neurofeedback training; this was mainly driven by an ipsilateral alpha increase. Surprisingly, comparing pre- to post-training, detection performance decreased for a Gabor stimulus presented in the hemifield that was un-attended during neurofeedback. This effect was not observed in the sham group. Thus, neurofeedback training alters alpha lateralization, which in turn decreases performances in the untrained hemifield. Our findings suggest that alpha oscillations play a causal role for the allocation of attention. Furthermore, our neurofeedback protocol serves to reduce the detection of unattended visual information and could therefore be of potential use for training to reduce distractibility in attention deficit patients, but also highlights that neurofeedback paradigms can have negative impact on behavioral performance and should be applied with caution.
authors.affiliation: Department of Life Sciences, University of Tokyo, Tokyo 153-8902, Japan; Donders Institute for Brain, Cognition and Behaviour, Radboud University, 6500HB Nijmegen, the Netherlands. Electronic address: y.okazaki@brain.riken.jp.
authors.forename: Yuka O
authors.initials: YO
authors.lastname: Okazaki
authors.affiliation: Donders Institute for Brain, Cognition and Behaviour, Radboud University, 6500HB Nijmegen, the Netherlands. Electronic address: jm.horschig@donders.ru.nl.
authors.forename: Jörn M
authors.initials: JM
authors.lastname: Horschig
authors.affiliation: Donders Institute for Brain, Cognition and Behaviour, Radboud University, 6500HB Nijmegen, the Netherlands; Behavioural Science Institute, Radboud University, 6525HR Nijmegen, the Netherlands.
authors.forename: Lisa
authors.initials: L
authors.lastname: Luther
authors.affiliation: Donders Institute for Brain, Cognition and Behaviour, Radboud University, 6500HB Nijmegen, the Netherlands.
authors.forename: Robert
authors.initials: R
authors.lastname: Oostenveld
authors.affiliation: Department of Life Sciences, University of Tokyo, Tokyo 153-8902, Japan; Department of Psychology, University of Tokyo, Tokyo 113-0033, Japan. Electronic address: ikuya@l.u-tokyo.ac.jp.
authors.forename: Ikuya
authors.initials: I
authors.lastname: Murakami
authors.affiliation: Donders Institute for Brain, Cognition and Behaviour, Radboud University, 6500HB Nijmegen, the Netherlands. Electronic address: ole.jensen@donders.ru.nl.
authors.forename: Ole
authors.initials: O
authors.lastname: Jensen
mesh_terms: D000293:Adolescent; D000328:Adult; D000513:Alpha Rhythm / Q000502:physiology*; D001288:Attention / Q000502:physiology; D001676:Biofeedback, Psychology / Q000379:methods*; D003071:Cognition / Q000502:physiology; D003463:Cues; D005145:Face; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D007858:Learning / Q000502:physiology; D015225:Magnetoencephalography / Q000379:methods*; D008297:Male; D010775:Photic Stimulation; D011597:Psychomotor Performance / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*; D055815:Young Adult
keywords: Alpha lateralization; Attention; Brain computer interface (BCI); Magnetoencephalography (MEG); Neurofeedback; Plasticity