Jarmo Arvid Hämäläinen

Visual attention comprises alerting, orienting, and executive-control networks. Although these networks are behaviourally evident in childhood, age differences in the neural processes supporting them remain unclear. Typically developing 12–13-year-old children (n = 77) and 19–33-year-old adults (n = 21) performed the Attention Network Test while electroencephalography (EEG) was recorded. Behavioural performance was assessed using reaction time and accuracy. Neural processing was examined using event-related potentials (N1 and P3 amplitudes and latencies) and induced time–frequency analyses of theta (4–7 Hz), alpha (8–12 Hz), and beta (13–25 Hz) band activity. Significant alerting, orienting, and executive-control effects were observed in reaction time, with children responding more slowly overall than adults. Children showed longer N1 latencies than adults during the orienting comparison, indicating slower early target-related processing. Alerting cues increased target-related N1 amplitudes similarly in both groups. Adults, but not children, showed smaller P3 amplitudes for incongruent than congruent trials, whereas children showed larger P3 amplitudes overall, suggesting age-related differences in conflict-related processing. Time–frequency analyses showed that alerting modulated theta-, alpha-, and beta-band activity similarly in both groups. Orienting-related theta activity differed between age groups, with children showing higher theta power for spatial- than centre-cue trials. Alpha-band activity also differed between orienting conditions similarly in both groups. These findings indicate that children and adults can show comparable behavioural attentional network effects despite differences in neural processing. The results further suggest that electrophysiological measures of attentional processing show age-related differences beyond late childhood.

We investigated how auditory and visual presentation of small numerical magnitudes and non- numerical magnitudes are passively processed at the neural level. Earlier research suggests automatic processing of quantities occurs rapidly in the brain. However, there are no studies on passive, pre-attentive change detection of magnitudes utilizing mismatch negativity (MMN) across sensory modalities in same participants, important to understand amodal processing of magnitudes. We recorded EEG in passive auditory and visual multi-feature oddball and control paradigms from the same adult individuals (N=104/105, respectively). In the auditory paradigm, the standard stimulus was a 2-part sound, while the deviant stimuli varied in frequency, intensity, gap length, and number of sounds (1-part and 3-part stimuli). In the visual paradigm, the standard stimulus was a dot array containing two medium-sized dots, while the deviant stimuli varied in numerosity (1 or 3 dots) and dot size (small or large). The results for the auditory paradigm showed significant MMN across all features, including comparisons with deviant-alone control stimuli, except for the 2-part vs. 1-part contrast. The results for the visual paradigm suggested differences in processing across all features apart from large and medium-size stimuli. These results replicate earlier MMN findings that the brain distinguishes pre-attentively changes in sound frequency, amplitude and gap. Auditorily presented small numerical magnitudes also showed pre-attentive processing but less robustly to the contrast 2 vs. 1. Visual pre-attentive processing of small numerical magnitudes was also observed. Together these findings could be interpreted to support the existence of abstract, pre- attentive processing of numerical magnitudes. Highlights: • Auditory and visual processing of numerical and non-numerical magnitudes was examined with EEG • Auditory non-numerical magnitudes and medium vs. small dots replicated earlier MMN studies • aMMN and vMMN showed pre-attentive processing of changes in small numerosities 2 vs. 3 and 2 vs. 1 • 2 vs. 1 tone processing was less robust than 2 vs. 3 or the processing of the visual contrasts • The brain processes changes in small non-symbolic magnitudes pre-attentively

Human infants are assumed to be born with an innate understanding of quantities—a number sense— that enables them to detect non-symbolic number differences, for example, between sets of objects. This early ability has been found to be a predictor of later math skills. The assumption of innateness is based largely on studies in infants at 6 months of age or older and using visual stimuli with large numerosities, or in studies lacking statistical power. Using EEG, we studied pre-attentive discrimination for auditorily presented non-verbal numerical and non-numerical magnitudes of sleeping newborns (N = 104) to investigate whether the newborn auditory system is discriminating the number of sequentially presented sounds. The results showed that the 2-part repeated standard sound was discriminated from 3-part deviating sound and from 1-part deviating sound. As also the responses to 3-part sound differed from the responses of the same stimulus presented alone as a control, these results suggest that the difference between 2-part repeated sound and 3-part deviant sound is not merely due to physical features of the stimuli but reflects processing of numerosity. These results suggest that newborn infants are able to pre-attentively process at least some differences in the number of stimuli supporting the view of innateness of numerical magnitude discrimination. As the earlier evidence for innateness in newborns is limited, our study utilising small numerosities and auditory modality instead of vision—given the confounds in visual paradigms—offers complementary results on the innate brain processing on numerical information.

The sleeping brain can discriminate speech sounds, but evidence for cross‐night changes in neural responses to foreign speech in adults remains limited. Here, Finnish‐speaking adults naïve to tonal languages were exposed during Stage N2 of non‐rapid eye movement (NREM) sleep to small and large deviations in tone (pitch contour) embedded in vowel /a/ across four consecutive nights, while electroencephalography was recorded. Event‐related potentials (ERPs) P2 and P450 revealed robust change detection responses to tone deviations during sleep, and importantly, P450 amplitude decreased from night 1 to night 4. No evidence of perceptual learning was found in waking change detection ERPs or in behavioural performance measured with the same stimuli before and after the four‐night sleep exposure. In conclusion, the sleeping brain remained sensitive to deviations in vowel tone, and the amplitude reduction of the late ERP deflection suggests a change in auditory processing across nights of exposure. However, in the absence of transfer effects to wakeful measures, these findings do not provide evidence for phonetic learning‐related plasticity, and the extent to which the effects are speech‐specific remains unclear. These findings provide new insight into the dynamics of auditory processing during sleep and contribute to broader neuroscientific understanding of sensory processing in altered states of consciousness.

Native speakers generally outperform non-native speakers in identifying and discriminating speech sounds. Yet, the categorical perception of native speech sounds can sometimes impede the discrimination of sounds within the same phonemic category. It remains unclear whether different linguistic features show similar patterns in cross-linguistic comparisons. Therefore, we studied the categorization and discrimination of vowel duration and lexical tone—two features that differ fundamentally. Vowel duration (short vs. long) typically requires phonemic context for categorization, while tone (rising vs. falling) can be recognized directly from acoustics. Participants were native Finnish and Mandarin Chinese speakers, and native Mandarin Chinese speakers exposed to Finnish. As expected, Mandarin speakers demonstrated a steeper category boundary for tonal stimuli than Finnish speakers. In contrast, no group difference was found for categorization slope for duration. In discrimination, native speakers outperformed non-native speakers for between-category pairs, as anticipated. For within-category pairs, however, native speakers performed worse than non-native speakers—but only for the tone feature. Mandarin speakers exposed to Finnish showed differences in categorization of vowel duration and in associated reaction times compared with the other groups. The results suggest that native language does not influence vowel perception uniformly across tone and duration features. Moreover, exposure to a foreign language in adulthood may, at least initially, lead to categorization preferences that diverge from, rather than align with, those of native speakers. These findings provide a basis for future theoretical models of how native language and late exposure shape speech perception across different phonetic features.

Automaticity in decoding print is crucial for fluent reading. This process relies on associative memories between letters and speech sounds (LSS) that are overlearned through years of reading practice. While previous neuroimaging studies have identified neural correlates of LSS integration across different stages of reading development, the specific neural signatures underlying automatic LSS integration remain unclear. In the present study, we aimed to isolate neural components specifically associated with automatic LSS integration in literate adults. To this end, we developed an artificial script training paradigm in which adult native Finnish speakers were taught to associate unfamiliar foreign letters with familiar Finnish speech sounds. Using magnetoencephalography (MEG), we directly compared the audiovisual processing of newly learned and overlearned LSS associations within the same task, one day after training. Event-related fields (ERFs) and multivariate decoding revealed largely shared neural circuits of audiovisual integration for both types of LSS associations, as evidenced by multisensory interaction and congruency effects. Interestingly, the processing of congruent overlearned audiovisual associations uniquely recruited brain activity in the left medial parietal cortex during the 235–475 ms time window. Furthermore, temporal generalization analysis of the congruency effects revealed that while both newly learned and overlearned audiovisual associations engaged common neural mechanisms, the newly learned associations were processed systematically more slowly by a few hundred milliseconds. Our study identified the spatiotemporal neural signatures underlying automatized LSS processing, offering insights into neural markers that may help identify levels of reading proficiency.

Automaticity in decoding print is crucial for fluent reading. This process relies on associative memories between letters and speech sounds (LSS) that are overlearned through years of reading practice. While previous neuroimaging studies have identified neural correlates of LSS integration across different stages of reading development, the specific neural signatures underlying automatic LSS integration remain unclear. In the present study, we aimed to isolate neural components specifically associated with automatic LSS integration in literate adults. To this end, we developed an artificial script training paradigm in which adult native Finnish speakers were taught to associate unfamiliar foreign letters with familiar Finnish speech sounds. Using magnetoencephalography (MEG), we directly compared the audiovisual processing of newly learned and overlearned LSS associations within the same task, one day after training. Event-related fields (ERFs) and multivariate decoding revealed largely shared neural circuits of audiovisual integration for both types of LSS associations, as evidenced by multisensory interaction and congruency effects. Interestingly, the processing of congruent overlearned audiovisual associations uniquely recruited brain activity in the left parietal cortex during the 235-475 ms time window. Furthermore, temporal generalization analysis of the congruency effects revealed that while both newly learned and overlearned audiovisual associations engaged common neural mechanisms, the newly learned associations were processed systematically more slowly by a few hundred milliseconds. Our study identified the spatiotemporal neural signatures underlying automatized LSS processing, offering insights into neural markers that may help identify levels of reading proficiency.

Auditory brain responses’ longitudinal interplay with print exposure and their effects on reading skills were examined in children aged 4–10 years. Print exposure was represented by parent–child shared reading and children’s independent engagement, whereas speech/non-speech stimuli were used to evoke brain responses (N250). We evaluated the roles of familial risk (dyslexia) and parental education and found a link between print exposure and brain responses to speech at two timepoints in the longitudinal path model. A reciprocal association existed between independent print exposure and brain responses to speech, whereas speech/non-speech brain responses predicted school-age independent print exposure. Shared reading was positively associated with brain responses to speech stimuli at age 9, whereas independent print exposure was associated with later reading fluency. Family risk for dyslexia predicted reading accuracy and fluency, which did not run via print exposure or brain responses. The underlying mechanisms require further investigation by combining environmental, genetic predisposition and brain and skill development models. Corresponding author: ariane.a.tretow@jyu.fi