Dynamics of working memory for moving sounds:: An event-related potential and scalp current density study

• Published in: NeuroImage (Orlando, Fla.) Vol. 19; no. 4; pp. 1427 - 1438
• Main Authors: Kaiser, Jochen, Bertrand, Olivier
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.08.2003; Elsevier Limited
• Subjects: Acoustic Stimulation; Adult; Auditory working memory; Brain; Brain Mapping; Delayed matching-to-sample; Dominance, Cerebral - physiology; Electroencephalography; Event-related potential; Evoked Potentials, Auditory - physiology; Female; Frontal Lobe - physiology; Human subjects; Humans; Male; Memory, Short-Term - physiology; Nerve Net - physiology; Orientation - physiology; Parietal cortex; Parietal Lobe - physiology; Pitch Discrimination - physiology; Psychoacoustics; Scalp current density; Signal Processing, Computer-Assisted; Slow wave; Sound; Sound Localization - physiology; Sound motion; Sound Spectrography; Spatial hearing; Studies; Temporal Lobe - physiology; Auditory working memory; Human subjects; Event-related potential; Delayed matching-to-sample; Slow wave; Parietal cortex; Scalp current density; Electroencephalography; Spatial hearing; Sound motion
• ISSN: 1053-8119; 1095-9572
• DOI: 10.1016/S1053-8119(03)00233-7

Human brain imaging studies have suggested that posterior temporo-parietal regions are involved in auditory spatial processing. We used electroencephalography to investigate the dynamics of temporo-parietal networks during working memory for moving sounds. A delayed matching-to-sample task required a decision on the identity of positions and trajectories of two moving sounds S1 and S2 presented with delays of 927 or 1427 ms. Moving sounds consisted of noise bursts positioned at successive angles to create the impression of one of six possible trajectories at variable spatial positions. Stimuli in the equally difficult control condition were identical to the memory task up to S2, which was replaced by a spatial displacement in the otherwise stationary background sound whose direction had to be detected. Event-related potentials were recorded from 31 scalp electrodes in 15 subjects. Scalp current density estimates allowed to identify the following components. The fronto-central negative variation preceding S2 did not differ between tasks. In contrast, the sustained negative current during the presentation of S1 originating from superior temporal cortex was more pronounced for the memory task, probably reflecting enhanced attention allocation and foreground-background discrimination. Most importantly, the memory task activated current sources over bilateral posterior parietal regions between the middle of S1 and the end of the delay phase. This component was completely absent in the control condition. In summary, the present study disclosed varying degrees of memorization-related, top-down driven influences on the processing of moving sounds at different stages of an auditory network involving temporal and parietal regions.