title: Brain dynamics that correlate with effects of learning on auditory distance perception.
abstract: Accuracy in auditory distance perception can improve with practice and varies for sounds differing in familiarity. Here, listeners were trained to judge the distances of English, Bengali, and backwards speech sources pre-recorded at near (2-m) and far (30-m) distances. Listeners' accuracy was tested before and after training. Improvements from pre-test to post-test were greater for forward speech, demonstrating a learning advantage for forward speech sounds. Independent component (IC) processes identified in electroencephalographic (EEG) data collected during pre- and post-testing revealed three clusters of ICs across subjects with stimulus-locked spectral perturbations related to learning and accuracy. One cluster exhibited a transient stimulus-locked increase in 4-8 Hz power (theta event-related synchronization; ERS) that was smaller after training and largest for backwards speech. For a left temporal cluster, 8-12 Hz decreases in power (alpha event-related desynchronization; ERD) were greatest for English speech and less prominent after training. In contrast, a cluster of IC processes centered at or near anterior portions of the medial frontal cortex showed learning-related enhancement of sustained increases in 10-16 Hz power (upper-alpha/low-beta ERS). The degree of this enhancement was positively correlated with the degree of behavioral improvements. Results suggest that neural dynamics in non-auditory cortical areas support distance judgments. Further, frontal cortical networks associated with attentional and/or working memory processes appear to play a role in perceptual learning for source distance.
authors.affiliation: 711th Human Performance Wing, U. S. Air Force Research Laboratory Wright-Patterson Air Force Base, OH, USA ; Department of Psychology, University at Buffalo, The State University of New York Buffalo, NY, USA.
authors.forename: Matthew G
authors.initials: MG
authors.lastname: Wisniewski
authors.affiliation: Department of Psychology, University at Buffalo, The State University of New York Buffalo, NY, USA.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Mercado
authors.affiliation: Department of Psychology, University at Buffalo, The State University of New York Buffalo, NY, USA.
authors.forename: Barbara A
authors.initials: BA
authors.lastname: Church
authors.affiliation: Biological Psychology and Neuroergonomics, Berlin Institute of Technology Berlin, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Gramann
authors.affiliation: Swartz Center for Computational Neuroscience, Institute for Neural Computation, University of California, San Diego San Diego, CA, USA.
authors.forename: Scott
authors.initials: S
authors.lastname: Makeig
keywords: electroencephalography (EEG); event-related spectral perturbation (ERSP); familiarity; independent component analysis (ICA); perceptual learning; ranging