Right hemisphere occipital rTMS impairs working memory in visualizers but not in verbalizers.
Sven Hilbert, Michaela McAssey, Markus Bühner, Patrick Schwaferts, Monika Gruber, Stephan Goerigk, Paul Christopher John Taylor
Author Information
Sven Hilbert: Faculty of Psychology, Educational Science, and Sport Science, University of Regensburg, Universitätsstraße 31, 93053, Regensburg, Germany. sven.hilbert@ur.de.
Michaela McAssey: Department of Neurology, University Hospital, LMU Munich, Munich, Germany.
Markus Bühner: Department of Psychology, Psychological Methods and Assessment, LMU Munich, Leopoldstraße 13, 80802, München, Germany.
Patrick Schwaferts: Institute of Statistics, Methodological Foundations of Statistics and its Applications, Ludwigstraße 33, 80539, München, Germany.
Monika Gruber: Department of Psychology, Psychological Methods and Assessment, LMU Munich, Leopoldstraße 13, 80802, München, Germany.
Stephan Goerigk: Department of Psychiatry and Psychotherapy, Ludwig-Maximilians-University, Nußbaumstraße 7, 80336, Munich, Germany.
Paul Christopher John Taylor: Department of Neurology, University Hospital, LMU Munich, Munich, Germany. ORCID
Distinguishing between verbal and visual working memory processes is complicated by the fact that the strategy used is hard to control or even assess. Many stimuli used in working memory tasks can be processed via verbal or visual coding, such as the digits in the digit span backwards task (DSB). The present study used repetitive transcranial magnetic stimulation (rTMS) to examine the use of visual processing strategies in the DSB. A total of 47 German university students took part in the study, 23 spontaneously using a verbal processing strategy and 24 using a visual strategy. After rTMS to the right occipital cortex, visualizers showed a significantly stronger mean performance decrease compared to verbalizers. The results indicate that the visual cortex is more critical for visualizers compared to verbalizers in the DSB task. Furthermore, the favored processing modality seems to be determined by the preference for a cognitive strategy rather than the presentation modality, and people are aware of the applied strategy. These findings provide insight into inter-individual differences in working memory processing and yield important implications for laboratory studies as well as clinical practice: the stimulus does not necessarily determine the processing and the participant can be aware of that.
