Description
(Text)
Auditory processing during an important period in childhood, namely school-age years, has been in the focus of the current thesis. Event-related potentials (ERPs) and fields (ERFs) were used to investigate obligatory tone frequency processing and deviancy detection in children and adults. Although ERPs in children differ greatly from those obtained in adults, the underlying generators and functions may be similar. This issue was addressed in the first experiment of the current work. The two subsequent experiments focused on maturational changes in discriminative processing abilities, more specifically, auditory deviancy detection as indexed by the mismatch negativity (MMN). It has been argued that ERP indices of obligatory tone processing (N1) and deviancy detection (MMN) are highly related, if not the same. Thus, a paradigm was developed that allows the disentanglement of obligatory tone processing and deviancy processing.
The results are emphasizing three main findings related to auditory system maturation. First, obligatory auditory stimulus processing is conducted by similar cortical areas in school-age children and adults, and, more specifically, frequency representations are obtained in a mature way by the age of nine to ten. Second, deviancy processing seems not to be mature by mid school-age when paradigms typically applied in adults are used. Third, when the auditory inflow is ordered more appropriately for children (i.e. slower pace, salient distractors, and/or when attended) deviancy detection may work comparable in children and adults, on the other hand, salient distractors appear to engage additional processing steps. Finally, we presented a more general finding: with the help of a controlled experimental paradigm, obligatory and deviancy related processes can be disentangled.
