title: A new electrophysiological index for working memory load in humans.
abstract: Working memory, the ability to store and simultaneously manipulate information, is affected in several neuropsychiatric disorders which lead to severe cognitive and functional deficits. An electrophysiological marker for this process could help identify early cerebral function abnormalities. In subjects performing working memory-specific n-back tasks, event-related potential analysis revealed a positive-negative waveform (PNwm) component modulated in amplitude by working memory load. It occurs in the expected time range for this process, 140-280 ms after stimulus onset, superimposed on the classical P200 and N200 components. Independent Component Analysis extracted two functional components with latencies and topographical scalp distributions similar to the PNwm. Our results imply that the PNwm represents a new electrophysiological index for working memory load in humans.
authors.affiliation: Neuroimaging Unit, Clinic of Geriatric Psychiatry, Department of Psychiatry, University Hospitals of Geneva, Chemin du Petit-Bel-Air 2, CH-1225 Chêne-Bourg, Geneva, Switzerland. Pascal.missonnier-evrard@hcuge.ch
authors.forename: Pascal
authors.initials: P
authors.lastname: Missonnier
authors.forename: Ute
authors.initials: U
authors.lastname: Leonards
authors.forename: Gabriel
authors.initials: G
authors.lastname: Gold
authors.forename: Julie
authors.initials: J
authors.lastname: Palix
authors.forename: Vincente
authors.initials: V
authors.lastname: Ibáñez
authors.forename: Panteleimon
authors.initials: P
authors.lastname: Giannakopoulos
mesh_terms: D000328:Adult; D001931:Brain Mapping; D004569:Electroencephalography; D004594:Electrophysiology; D005074:Evoked Potentials, Visual / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D010775:Photic Stimulation; D025341:Principal Component Analysis; D011932:Reading