title: ICA-derived cortical responses indexing rapid multi-feature auditory processing in six-month-old infants.
abstract: The abilities of infants to perceive basic acoustic differences, essential for language development, can be studied using auditory event-related potentials (ERPs). However, scalp-channel averaged ERPs sum volume-conducted contributions from many cortical areas, reducing the functional specificity and interpretability of channel-based ERP measures. This study represents the first attempt to investigate rapid auditory processing in infancy using independent component analysis (ICA), allowing exploration of source-resolved ERP dynamics and identification of ERP cortical generators. Here, we recorded 60-channel EEG data in 34 typically developing 6-month-old infants during a passive acoustic oddball paradigm presenting 'standard' tones interspersed with frequency- or duration-deviant tones. ICA decomposition was applied to single-subject EEG data. The best-fitting equivalent dipole or bilaterally symmetric dipole pair was then estimated for each resulting independent component (IC) process using a four-layer infant head model. Similar brain-source ICs were clustered across subjects. Results showed ERP contributions from auditory cortex and multiple extra-auditory cortical areas (often, bilaterally paired). Different cortical source combinations contributed to the frequency- and duration-deviant ERP peak sequences. For ICs in an ERP-dominant source cluster located in or near the mid-cingulate cortex, source-resolved frequency-deviant response N2 latency and P3 amplitude at 6 months-of-age predicted vocabulary size at 20 months-of-age. The same measures for scalp channel F6 (though not for other frontal channels) showed similar but weaker correlations. These results demonstrate the significant potential of ICA analyses to facilitate a deeper understanding of the neural substrates of infant sensory processing.
authors.affiliation: Department of Electronics Information and Bioengineering, Politecnico di Milano, Milano, Italy; Bioengineering Lab, Scientific Institute IRCCS Eugenio Medea, Bosisio Parini, Lecco, Italy. Electronic address: caterina.piazza@polimi.it.
authors.forename: Caterina
authors.initials: C
authors.lastname: Piazza
authors.affiliation: Department of Developmental Neuropsychology, Scientific Institute, IRCCS Eugenio Medea, Bosisio Parini, Lecco, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Cantiani
authors.affiliation: Swartz Center for Computational Neuroscience, Institute for Neural Computation, University of California San Diego, La Jolla, CA, USA.
authors.forename: Zeynep
authors.initials: Z
authors.lastname: Akalin-Acar
authors.affiliation: Swartz Center for Computational Neuroscience, Institute for Neural Computation, University of California San Diego, La Jolla, CA, USA.
authors.forename: Makoto
authors.initials: M
authors.lastname: Miyakoshi
authors.affiliation: Center for Molecular & Behavioral Neuroscience, Rutgers University, Newark, NJ, USA.
authors.forename: April A
authors.initials: AA
authors.lastname: Benasich
authors.affiliation: Bioengineering Lab, Scientific Institute IRCCS Eugenio Medea, Bosisio Parini, Lecco, Italy.
authors.forename: Gianluigi
authors.initials: G
authors.lastname: Reni
authors.affiliation: Department of Electronics Information and Bioengineering, Politecnico di Milano, Milano, Italy.
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Bianchi
authors.affiliation: Swartz Center for Computational Neuroscience, Institute for Neural Computation, University of California San Diego, La Jolla, CA, USA.
authors.forename: Scott
authors.initials: S
authors.lastname: Makeig
mesh_terms: D001303:Auditory Cortex / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods*; D003627:Data Interpretation, Statistical; D004569:Electroencephalography / Q000379:methods; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D009415:Nerve Net / Q000502:physiology*; D010898:Pitch Perception / Q000502:physiology*; D025341:Principal Component Analysis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
keywords: EEG; Event-related potential; Independent component analysis; Infants; Rapid auditory discrimination; Source localization