The spatial nature of ordinal information in verbal working memory

• Main Author: Antoine, Sophie
• Other Authors: Gevers, Wim
• Format: Doctoral Thesis
• Language: en
• Published: Universite Libre de Bruxelles 2016
• Subjects: Psychologie cognitive; Neurosciences cognitives; Neuropsychologie; space processing; serial order; verbal working memory; hemispatial neglect; TMS
• Online Access: http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/238833

At the beginning of this work, recent studies had evidenced a tight link between serial order in verbal working memory and space processing. In a first study, we investigated the nature of this link. By discarding the possibility that it results from conceptual associations, our results favoured the idea that the representation of serial order is intrinsically of a spatial nature. This led us to hypothesize that a deficit of space processing should be accompanied by a deficit of serial order. To test this hypothesis, we investigated verbal working memory abilities in a group of brain-damaged patients with hemispatial neglect, a syndrome characterized by a deficit of spatial attention. We showed that these patients have a specific deficit for serial order, as they showed difficulties when judging the ordinal relations between memorized items, whereas they were able to judge the identity of these items. This deficit of serial order was related to hemispatial neglect severity and to posterior parietal lesions. We formulated the hypothesis that the link between serial order and space results from the overlap of brain networks subtending these cognitive processes, at the level of the posterior parietal cortex. To test this hypothesis, we used transcranial magnetic stimulation (TMS) to temporarily disrupt this area in healthy participants, with the prediction that TMS would induce a similar bias when judging the position of a landmark on horizontal lines (spatial task), and when judging the position of an item in memorized sequences (ordinal task). In line with previous studies, TMS induced a bias in the spatial task. However, contrary to our prediction, TMS over the same area in the same participants did not induce a similar bias in the ordinal task. === Doctorat en Sciences psychologiques et de l'éducation === info:eu-repo/semantics/nonPublished