Search Abstracts | Symposia | Slide Sessions | Poster Sessions
Slide Session A: Early Development & Structural Maturation
Wednesday, September 30, 10:00 - 10:45 am, Amphitheatre D
Talk 1: Newborns’ Brains Detecting Foreign Rhythm in Native-Language Speech
Martina Dvorakova1,2, Natálie Kikoťová1,4, Josef Urbanec3, Kateřina Chládková1,2; 1Institute of Psychology, Czech Academy of Sciences, 2Charles University, Czech Republic, 3Havlíčkův Brod Hospital, Czech Republic, 4Eberhard Karls Universität, Germany
Human sensitivity to language begins before birth. During prenatal development, fetuses are primarily exposed to low-frequency and temporal properties of speech, especially rhythm and intonation, because higher-frequency information is attenuated in the womb (Gerhardt & Abrams, 2000; Richards et al., 1992). Previous research has shown that newborns can discriminate between their native language and unfamiliar languages and are sensitive to prosodic structure shortly after birth (Mehler et al., 1988; Moon et al., 1993; Nazzi et al., 1998; May et al., 2018). Traditional theories proposed that infants discriminate languages mainly when those languages belong to different rhythm classes, such as stress-timed versus syllable-timed languages (Mehler et al., 1996; Nazzi et al., 1998). More recent approaches, however, argue that infants rely on gradient acoustic and temporal cues rather than categorical rhythm classes alone (Gasparini et al., 2021; Paillereau et al., 2021; Paillereau & Chládková, 2024). The present study investigated whether temporal rhythm cues by themselves are sufficient for newborns to distinguish between native and foreign rhythmic patterns in speech. Czech-learning newborns listened to naturally produced Czech sentences spoken either with native Czech rhythm or with an experimentally manipulated foreign rhythm while their cortical activity was measured using functional near-infrared spectroscopy (fNIRS). The two speech conditions differed primarily in temporal timing patterns: in the foreign-rhythm condition, stressed syllables were lengthened and unstressed syllables shortened, while lexical content, segmental structure, and overall sentence duration remained unchanged. Forty-four healthy Czech newborns participated in the experiment. Infants were tested while asleep, and hemodynamic responses were recorded from bilateral frontal and centro-temporal regions associated with auditory speech processing. The results showed that newborns processed the two rhythmic varieties differently: LME modelling the HbO change detected a main effect of condition and an interaction of condition and hemisphere. Speech with foreign rhythm elicited stronger oxygenated hemoglobin (HbO) responses than speech with native rhythm. Importantly, this effect was strongest in the right hemisphere, suggesting early right-lateralized processing of speech rhythm and prosody. These findings demonstrate that sensitivity to temporal rhythm cues is present already at birth. Newborns discriminated between the two speech varieties relying primarily on gradient temporal cues, even though the stimuli fell outside traditional rhythm-class distinctions such as stress-timed versus syllable-timed languages. The results therefore support contemporary accounts of early language development that emphasize multidimensional and gradient acoustic processing rather than categorical rhythm-class perception alone. The study also contributes to research on hemispheric specialization in early language processing. Previous work has associated the right hemisphere with prosodic processing, particularly rhythm and intonation (Poeppel, 2003; Gervain et al., 2008; Martinez-Alvarez et al., 2023), and the present findings extend this evidence to newborn perception of naturalistic speech rhythm. Finally, the experiment used ecologically valid speech materials: continuous, naturally produced sentences rather than synthetic or backward speech often used in infant research. The findings therefore provide evidence that newborns can process subtle temporal properties of real-world speech from the very beginning of life.
Talk 2: Maturation of the structural language network in relation to language development around 1 year of age
Cheslie C. Klein1,2, Angela D. Friederici2, Charlotte Grosse Wiesmann1,2; 1University of Technology Nuremberg, Nuremberg, Germany, 2Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
The arcuate fasciculus is a crucial fiber pathway supporting language functions. Predominantly left-lateralized, it comprises distinct subsegments connecting the temporal cortex to the posterior part of Broca’s area (pathway to BA44) and the premotor cortex (pathway to BA6). These pathways support distinct language functions in adults and follow different developmental trajectories. While the pathway to BA44 undergoes prolonged maturation, the pathway to BA6 is relatively mature at birth. Though both show pronounced left-lateralization in preschoolers, only increased left-lateralization in the pathway to BA44 pathway links to sentence processing. Much less is known about the maturation and lateralization of these two pathways during infancy, despite being a critical period for language acquisition. To address this, we investigated a cross-sectional sample of 64 monolingual German infants aged 9 to 15 months, centered around 12 months when first words are typically produced. We reconstructed the two pathways using diffusion-weighted MRI data acquired during natural sleep. To assess the maturation and lateralization of each pathway, we analyzed the total streamline count and the fractional anisotropy (FA) profile along 100 equidistant nodes. Additionally, we assessed infants’ language development using a standardized behavioral battery. Our results indicate that the pathway to BA6 exhibits significant left-lateralization in streamline count. Additionally, the tract profile showed two peaks indicating pronounced left-lateralization in the anterior-horizontal and posterior-vertical portions, consistent with previous findings in preschoolers. Conversely, the pathway to BA44 showed no clear lateralization in streamline count. The tract profile of the pathway to BA44 showed a peak with pronounced left-lateralization of FA in the posterior-vertical segment towards the parietal lobe, similar to preschoolers. In contrast, the anterior-horizontal segment exhibited no clear lateralization, tending toward the right hemisphere. Left-lateralization in this segment increased with age between 9 and 15 months as identified by a cluster-based permutation test. When investigating how these fiber pathways support language functions, we found that FA in the posterior portion of the left pathway to BA6 was significantly related to infants’ language development. Overall, these results suggest that the pathway to BA6 is largely mature and left-lateralized in infancy, aligning with previous findings in newborns. The lateralization of the pathway to BA44 appears to follow a posterior-to-anterior developmental trajectory, with the anterior portion still relatively immature. The increase in left-lateralization of this segment with infants’ age suggests a critical maturational process. Interestingly, language functions were related to the maturation of the left pathway to BA6. Given that the pathway to BA44 is still immature, the pathway to BA6 may support early language functions in 1-year-olds. While previous work has often investigated the arcuate fasciculus as a single tract, our findings demonstrate that the maturation trajectories in infancy differ between its subsegments. This sheds light on the ontogeny of the arcuate fasciculus and the specific roles its subsegments play in language development. In addition to long-range fiber pathways, we will also reconstruct short-association fibers connecting to BA44 within Broca’s area and towards BA6 to examine their maturation and relation to language functions in the same cohort.
Talk 3: Thalamocortical Connectivity Facilitates Faster Response Time for High Frequency Lexical Items in Picture Naming
Judah Huberman-Shlaes1, Jiahao J. Chen1, Eliza Reedy1, Julien Dirani2, Raouf Belkhir1, Sirisha Nouduri1, Mahmood Abdelkader1, Arianna Damiani1, Bradford Z. Mahon2, Jorge Gonzalez-Martinez1, Arka N. Mallela3; 1University of Pittsburgh Medical Center Department of Neurological Surgery, 2Carnegie Melon University, 3Rush University Medical Center Department of Neurosurgery and Rush Epilepsy Center
Most models of the neural basis of language emphasize cortico-cortical interactions, but subcortical structures, particularly the pulvinar, are increasingly implicated. Prior work has demonstrated that the pulvinar can modulate responses in various cortical regions. Drawing on lesion studies that have shown that pulvinar damage can disrupt language processing, we hypothesized that the pulvinar coordinates processing between the inferior frontal gyrus and the temporal lobe. To test this, we evaluated how lexical variables modulate pulvinar–cortical connectivity. We examined interactions between low-frequency thalamic activity and cortical high-gamma activity (70–200 Hz). Using stereotactic EEG (sEEG) in patients with drug-resistant epilepsy, we tested whether these dynamics facilitate cortical information transfer during lexical retrieval, and track lexical frequency, an index of the speed of lexical access. Nine patients undergoing sEEG monitoring with cortical and pulvinar coverage completed a picture-naming task in which lexical frequency was factorially manipulated across a set of pictures. Pulvinar–cortical connectivity was estimated using nonlinear H², examining strength and direction of interactions between pulvinar delta–theta (1–8 Hz), alpha–beta (8–20 Hz), and low gamma (25–40 Hz) activity and cortical high-gamma activity (70–200 Hz). H² is a nonlinear, directional metric that captures dependencies between signals without assuming a specific underlying model. It captures both linear and nonlinear neural dynamics. Connectivity was assessed for modulation by lexical frequency (High vs. Low) and for associations with response time (RT). Higher-frequency items were associated with faster response times (t(609) = −1.97, p < 0.05). Lexical frequency also modulated pulvinar–cortical connectivity. Higher-frequency items showed stronger connectivity between the pulvinar and anterior MTG in the delta–theta band (Pulvinar → aMTG; β = 0.05, p < 0.03) and low gamma band (Pulvinar → aMTG; β = 0.06, p < 0.006). Similarly, higher-frequency items showed stronger connectivity between the pulvinar and the pars triangularis IFG in the delta–theta band (Pulvinar → IFG; β = 0.07, p < 0.03) and alpha–beta band (IFG → Pulvinar; β = 0.076, p < 0.09). We then tested if pulvinar-cortical activity was related to response speed (RT). Faster RT was associated with greater connectivity in the delta–theta band between the pulvinar and anterior MTG (Pulvinar → aMTG; β = −0.029, p < 0.02) as well as between the pulvinar and IFG triangularis (IFG → Pulvinar; β = −0.027, p = 0.014). Faster RTs were associated with increased connectivity as well between IFG triangularis and pulvinar in the alpha–beta band (IFG → Pulvinar; β = −0.038, p = 0.030). Pulvinar–cortical dynamics are modulated by lexical demands and directly relate to behavior. Heightened pulvinar-cortical connectivity was associated with higher lexical frequency items. Furthermore, this connectivity was also associated with faster processing speeds. These findings demonstrate a tight relation between pulvinar-cortical connectivity and word retrieval processes during picture naming. This raises the key issue of whether pulvinar-cortical connectivity supports the communication of linguistic content or is rather a general arousal signal to coordinate cortical-cortical connectivity that supports the actual exchange of linguistic content.
Talk 4: Anatomical and functional organization of Exner’ area in writing and reading and its evolutionary basis
Yang Yang1,2, Min Xu3, Jiaojian Wang4; 1State Key Laboratory of Cognitive Science and Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing, China, 2University of Chinese Academy of Sciences, Beijing, China, 3School of Psychology, Shenzhen University, Shenzhen, China, 4Yunnan Key Laboratory of Primate Biomedical Research, Kunming, China
Exner’s area is a functionally defined region of the motor cortex critical for writing and writing, yet its precise anatomical and functional localization and the origin of its specialization for written words remain poorly understood. Using tractography-based parcellation, we identified two anterior–posterior subregions within Exner’s area in both adults and children (ages 9–11), revealing previously unrecognized anatomical heterogeneity. The two subregions exhibited distinctions in task-evoked activation during handwriting and reading task, as well as in resting state functional connectivity (RSFC). To further unveil evolutionary origins of Exner’s functional selectivity, we conducted cross-species comparisons of anatomical parcellation and RSFC between humans and macaques. Despite that macaques exhibit a similar anterior–posterior anatomical organization, humans exhibited greater RSFC between the anterior subregion and language-related regions relative to macaques. These findings suggest that Exner’s area is built upon an evolutionarily conserved anatomical scaffold, with human-specific network reconfiguration associated with written language specialization, supporting the neuronal recycling theory. Finally, using a transcriptome–neuroimaging approach, we identified genes associated with human-specific functional connectivity of the anterior subregion, pointing to a molecular basis for its functional selectivity. Together, this study identified the anatomical and functional heterogeneity of Exner’s area and human-specific subdivisions, significantly advancing our understanding of how this unique motor cortex region contributes to written language processing.