Mismatch Detection

component around 250 ms of the ERP to deviant stimulus; R EP , ERP to early pitch deviant stimulus; R EO , ERP to standard stimulus with early onset; R TP , ERP to timely pitch deviant stimulus; R S , ERP to timely standard stimulus; RON, Reorienting negativity; SCD, Scalp Current Density.

Ungan et al. Responses to Early Auditory Changes that the temporal, frontal, and parietal MMN components are simultaneously present rather than emerging sequentially in time, supporting the MMN models based on parallel deviance processing in the respective cortices. Similarity of the RONs to timely and early pitch deviances indicated that reorienting of attention is of the same strength in two cases.

We propose and test the keyhole hypothesis-that measurements from low dimensional EEG, such as ear-EEG reflect a broadly distributed set of neural processes. We formulate the keyhole hypothesis in information theoretical terms. The experimental investigation is based on legacy data consisting of 10 subjects exposed to a battery of stimuli, including alpha-attenuation, auditory onset, and mismatch-negativity responses and a new medium-long EEG experiment involving data acquisition during 13 h. Linear models were estimated to lower bound the scalp-to-ear capacity, i.e., predicting ear-EEG data from simultaneously recorded scalp EEG. A cross-validation procedure was employed to ensure unbiased estimates. We present several pieces of evidence in support of the keyhole hypothesis: There is a high mutual information between data acquired at scalp electrodes and through the ear-EEG "keyhole," furthermore we show that the view-represented as a linear mapping-is stable across both ...

Ungan et al. Responses to Early Auditory Changes that the temporal, frontal, and parietal MMN components are simultaneously present rather than emerging sequentially in time, supporting the MMN models based on parallel deviance processing in the respective cortices. Similarity of the RONs to timely and early pitch deviances indicated that reorienting of attention is of the same strength in two cases.

This study shows for the first time that mispronunciation detection in 30-month-old children and adults can be measured using pupillometry. Compared to correctly pronounced words we found that mispronounced ones result in larger pupil dilations. For unrelated labels, which could either be a word or a non-word, we found different effects in children and adults. Children's pupillary responses for all unrelated labels were not different from those for correct labels whereas in adults we observed an increase in pupil size for unrelated words but not for non-words. Taking pupillary responses as an indicator of processing costs, we argue that for children as well as for adults a phonologically deviant word requires more resources to activate its matching entry in the mental lexicon compared to correctly pronounced words. Other measures like looking or reaction times are unable to capture this dimension in such a direct way.

An acoustic stimulus elicits an electroencephalographic response called auditory event-related potential (ERP). When some members of a stream of standard auditory stimuli are replaced randomly by a deviant stimulus and this stream is presented to a subject who ignores the stimuli, two different ERPs to deviant and standard stimuli are recorded. If the ERP to standard stimuli is subtracted from the ERP to deviant stimuli, the difference potential (DP) waveform typically exhibits a series of negative-positive-negative deflections called mismatch negativity (MMN), P3a, and reorienting negativity (RON), which are associated with pre-attentive change detection, involuntary attention switching, and reorienting of attention, respectively. The aim of the present study was to investigate how these pre-attentive processes are affected if the change occurs earlier than its usual timing implied by isochronous standard stimuli. In the MMN paradigm employed, 15% of the standards were randomly replaced by deviant stimuli which differed either in their pitch, their earlier onset time, or in both. Event-related responses to these three deviants [timely pitch change (R TP), earlier onset (R EO), earlier pitch change (R EP)] and to standards (R S) were recorded from 10 reading subjects. To maintain identical stimulation histories for the responses subtracted from each other, "deviant-standard" difference potentials (DP) for "timely" and "early" pitch deviances were derived as follows: DP TP = R TP − R S and DP EP = R EP − R EO. Interestingly, the MMN components of the DPs to timely and early pitch deviances had similar amplitudes, indicating that regularity of stimulus timing does not provide any benefit for the pre-attentive auditory change detection mechanism. However, different scalp current density (SCD) dynamics of the MMN/P3a complexes, elicited by timely and early pitch deviances, suggested that an auditory change in a stimulus occurring earlier-than-usual initiates a faster and more effective call-for-attention and causes stronger attention switching than a timely change. SCD results also indicated Abbreviations: DP, Difference Potential; DP EP , Difference Potential to early pitch deviance; DP TP , Difference Potential to timely pitch deviance; ERP, Event-related Potential; IOI, Inter-onset Interval; MMN, Mismatch Negativity; MMN EP , Mismatch Negativity to early pitch deviance; MMN TP , Mismatch Negativity to timely pitch deviance; P3a, The positive component around 250 ms of the ERP to deviant stimulus; R EP , ERP to early pitch deviant stimulus; R EO , ERP to standard stimulus with early onset; R TP , ERP to timely pitch deviant stimulus; R S , ERP to timely standard stimulus; RON, Reorienting negativity; SCD, Scalp Current Density.

This study shows for the first time that mispronunciation detection in 30-month-old children and adults can be measured using pupillometry. Compared to correctly pronounced words we found that mispronounced ones result in larger pupil dilations. For unrelated labels, which could either be a word or a non-word, we found different effects in children and adults. Children's pupillary responses for all unrelated labels were not different from those for correct labels whereas in adults we observed an increase in pupil size for unrelated words but not for non-words. Taking pupillary responses as an indicator of processing costs, we argue that for children as well as for adults a phonologically deviant word requires more resources to activate its matching entry in the mental lexicon compared to correctly pronounced words. Other measures like looking or reaction times are unable to capture this dimension in such a direct way.