Biology subjects

Friederici, A. D.

Publications and source records attributed to Friederici, A. D..

16 recordsLinked to original sources

bioRxiv2025

Grammar acquisition in preschool children is related to white matter maturation of the dorsal language network

In preschool years, children take important steps in grammar acquisition, which are essential to learning their native language. A central aspect is the acquisition of the morpho-syntactic rule system, which forms an intersection between words and sentences. In adults, rule-based linguistic processes are supported by the dorsal fiber pathway to BA44, the arcuate fascicle. This pathway matures relatively late in development, raising the question of whether it already supports grammar processes in the early preschool years, or whether early grammar acquisition is supported by different, earlier-maturing fiber pathways. In two independent samples of 3- to 5-year-old children (N = 90 and N = 30), we examined the association between the maturation of fiber pathways of the language network and childrens noun plural assignment as an index of their morpho-syntactic abilities. This revealed consistent differences between 3-year-olds and 4- to 5-year-olds. The 4- and 5-year-olds, but not 3-year-olds, showed a relation of morpho-syntax with both the dorsal pathway to BA44, supporting syntactic processes, and the dorsal pathway to BA6, supporting phonological processes in adults. Our results suggest that, in contrast to adults, preschool-aged children rely on both dorsal fiber pathways for morpho-syntax. This difference might point to different processing strategies reflecting the transition from phonology-based statistical learning to rule-based learning in grammar acquisition.

developmental biology↗

bioRxiv2024

Lifespan trajectory of chimpanzee brains characterized by magnetic resonance imaging histology

Chimpanzee brain maturation provides an invaluable framework for understanding the evolution of the human brain. We performed ultra-high resolution quantitative magnetic resonance imaging (qMRI) with histological validation on post mortem brains from captive and wild chimpanzees with a broad age range. We mapped developmental myelination and age-related iron accumulation across regions and layers of the neocortex. Compared to humans, chimpanzees showed more myelination and iron deposition in motor and premotor cortices, while the auditory cortex was more strongly myelinated in humans. Our model suggests that chimpanzees cortical myelination was largely completed by the age of nine years, while iron accumulation continued throughout the lifespan. The regions with highest adult levels of myelin and iron took the longest to mature, challenging the widespread assumption that highly myelinated regions complete their development first. The reported maps and developmental curves provide a foundation for comparative neuroscience research and understanding of human brain evolution.

neuroscience↗

bioRxiv2024

Characterizing directional dynamics of semantic prediction based on inter-regional temporal generalization

The event-related potential/field component N400(m) has been widely used as a neural index for semantic prediction. It has long been hypothesized that feedback information from inferior frontal areas plays a critical role in generating the N400. However, due to limitations in causal connectivity estimation, direct testing of this hypothesis has remained difficult. Here, magnetoencephalography (MEG) data was obtained during a classic N400 paradigm where the semantic predictability of a fixed target noun was manipulated in simple German sentences. To estimate causality, we implemented a novel approach based on machine learning and temporal generalization to estimate the effect of inferior frontal gyrus (IFG) on temporal areas. In this method, a support vector machine (SVM) classifier is trained on each time point of the neural activity in IFG to classify less predicted (LP) and highly predicted (HP) nouns and then tested on all time points of superior/middle temporal sub- regions activity (and vice versa, to establish spatio-temporal evidence for or against causality). The decoding accuracy was significantly above chance level when the classifier was trained on IFG activity and tested on future activity in superior and middle temporal gyrus (STG/MTG). The results present new evidence for a model predictive speech comprehension where predictive IFG activity is fed back to shape subsequent activity in STG/MTG, implying a feedback mechanism in N400 generation. In combination with the also observed strong feedforward effect from left STG/MTG to IFG, our findings provide evidence of dynamic feedback and feedforward influences between IFG and temporal areas during N400 generation.

neuroscience↗

bioRxiv2023

White matter plasticity during second language learning within and across hemispheres

Adult second language (L2) learning is a challenging enterprise inducing neuroplastic changes in the human brain. However, it remains unclear how the structural language connectome and its subnetworks change during adult L2-learning. The current study investigated longitudinal changes in white matter (WM) language networks in each hemisphere, as well as their interconnection, in a large group of Arabic-speaking adults who learned German intensively for six months. We found a significant increase in WM-connectivity within bilateral temporal-parietal semantic and phonological subnetworks and right temporal-frontal pathways mainly in the second half of the learning period. At the same time, WM-connectivity between the two hemispheres decreased significantly. Crucially, these changes in WM-connectivity are correlated with L2 performance. The observed changes in subnetworks of the two hemispheres suggest a network reconfiguration due to lexical learning. The reduced interhemispheric connectivity may indicate a key role of the corpus callosum in L2-learning by reducing the inhibition of the language-dominant left hemisphere. Our study highlights the dynamic changes within and across hemispheres in adult language-related networks driven by L2 learning. SignificanceThe neuroplastic changes induced by learning a second language (L2) in adulthood open up new perspectives for understanding brain function. The current study shows structural changes in the language network of Arabic native speakers who learned German intensively in two phases of three months each. We found a marked change in the left-hemispheric lexical-semantic language system and the right fronto-temporal pathway, accompanied by a decrease in white matter connectivity in the corpus callosum during L2 learning, which occurred mainly in the second period of L2 acquisition. The reduced interhemispheric connectivity suggests that the inhibitory role of the corpus callosum, relevant for native language processing, is reduced by L2 learning. Our findings demonstrate a clear experience-dependent structural plasticity in the human brain during L2 learning.

neuroscience↗

bioRxiv2023

Uncovering the Morphological Evolution of Language-Relevant Brain Areas

Human language is supported by a cortical network involving Brocas area which comprises Brodmann Areas 44 and 45 (BA44, BA45). While cytoarchitectonic homolog areas have been identified in nonhuman primates, it remains unknown how these regions evolved to support human language. Here, we use histological data and advanced cortical registration methods to precisely compare the morphology of BA44 and 45 between humans and chimpanzees. We found a general expansion of Brocas areas in humans, with the left BA44 enlarging the most, growing anteriorly into a region known to process syntax. Together with recent functional studies, our findings show that BA44 evolved from a purely action-related region to a more expanded region in humans, with a posterior portion supporting action and an anterior portion supporting syntactic processes. Furthermore, our findings provide a solution for the longstanding debate concerning the structural and functional evolution of Brocas area and its role in action and language.

neuroscience↗

bioRxiv2022

Children's syntax is supported by the maturation of BA44 at 4 years, but of the posterior STS at 3 years of age

Within the first years of life, children learn major aspects of their native language. However, the ability to process complex sentence structures, a core faculty in human language called syntax, has been found to emerge only slowly. A milestone in the acquisition of syntax is reached around the age of 4, when children learn a variety of syntactic concepts, including, for example, subordinate clauses. Here, we ask which maturational changes in the childs brain underlie the emergence of syntactic abilities around this critical age. We relate markers of cortical brain maturation to 3- and 4-year-olds syntactic in contrast to other language abilities. Our results show that distinct cortical brain areas support syntax in the two age groups: While 3-year-old childrens syntactic abilities were associated with increased surface area in the most posterior part of the left superior temporal sulcus, 4-year-old children showed an association with cortical thickness in the left posterior part of Brocas area, i.e. BA44. The present findings suggest that syntactic abilities rely on the maturation of distinct cortical regions in 3- compared to 4-year-olds. The observed shift to more mature regions involved in syntax may underlie the behavioral milestones in syntax acquisition around 4 years of age.

neuroscience↗

bioRxiv2022

Native language leaves distinctive traces in brain connections

The worlds languages differ substantially in their sounds, grammatical rules, and expression of semantic relations. While starting from a shared neural substrate, the developing brain must therefore have the plasticity to accommodate to the specific processing needs of each language. However, there is little research on how language-specific differences impacts brain function and structure. Here, we show that speaking typologically different languages leaves unique traces in the brains white matter connections of monolingual speakers of English (fixed word order language), German (with grammatical marking), and Chinese (tonal language). Using machine learning, we classified with high accuracy the mother tongue based on the participants patterns of structural connectivity obtained with probabilistic tractography. More importantly, connectivity differences between groups could be traced back to relevant processing characteristics of each native tongue. Our results show that the life-long use of a certain language leaves distinct traces in a speakers neural network.

neuroscience↗

bioRxiv2022

Assessing Quantitative MRI Techniques using Multimodal Comparisons

The study of brain structure and change in neuroscience is commonly conducted using macroscopic morphological measures of the brain such as regional volume or cortical thickness, providing little insight into the microstructure and physiology of the brain. In contrast, quantitative MRI allows the monitoring of microscopic brain change non-invasively in-vivo, and provides normative values for comparisons between tissues, regions, and individuals. To support the development and common use of qMRI for cognitive neuroscience, we analysed a set of qMRI metrics (R1, R2*, Magnetization Transfer saturation, Proton Density saturation, Fractional Anisotropy, Mean Diffusivity) in 101 healthy young adults. Here we provide a comprehensive descriptive analysis of these metrics and their linear relationships to each other in grey and white matter to develop a more complete understanding of the relationship to tissue microstructure. Furthermore, we provide evidence that combinations of metrics may uncover informative gradients across the brain by showing that lower variance components of PCA may be used to identify cortical gradients otherwise hidden within individual metrics. We discuss these results within the context of microstructural and physiological neuroscience research.

neuroscience↗

bioRxiv2022

White Matter Brain Structure Predicts Language Performance and Learning Success

Individual differences in the ability to deal with language have long been discussed. The neural basis of these, however, is yet unknown. Here we investigated the relationship between long-range white matter connectivity of the brain, as revealed by diffusion tractography, and the ability to process syntactically complex sentences in the participants native language as well as the improvement thereof by multi-day training. We identified specific network motifs that indeed related white matter tractography to individual language processing performance. First, for two such motifs, one in the left and one in the right hemisphere, their individual prevalence significantly predicted the individual language performance suggesting a predisposition for the individual ability to process syntactically complex sentences, which manifests itself in the white matter brain structure. Both motifs comprise a number of cortical regions, but seem to be dominated by areas known for the involvement in working memory rather than the classical language network itself. Second, we identified another left hemispheric network motif, whose change of prevalence over the training period significantly correlated with the individual change in performance, thus reflecting training induced white matter plasticity. This motif comprises diverse cortical areas including regions known for their involvement in language processing, working memory and motor functions. The present findings suggest that individual differences in language processing and learning can be explained, in part, by individual differences in the brains white matter structure. Brain structure may be a crucial factor to be considered when discussing variations in human cognitive performance, more generally.

neuroscience↗

bioRxiv2021

Individual alpha power predicts language comprehension

Alpha power attenuation during cognitive task performing has been suggested to reflect a process of release of inhibition, increase of excitability, and thereby benefit the improvement of performance. Here, we hypothesized that changes in individual alpha power during the execution of a complex language comprehension task may correlate with the individual performance in that task. We tested this using magnetoencephalography (MEG) recorded during comprehension of German sentences of different syntactic complexity. Results showed that neither the frequency nor the power of the spontaneous oscillatory activity at rest were associated with the individual performance. However, during the execution of a sentences processing task, the individual alpha power attenuation did correlate with individual language comprehension performance. Source reconstruction localized effects in temporal-parietal regions of both hemispheres. While the effect of increased task difficulty is localized in the right hemisphere, the difference in power attenuation between tasks of different complexity exhibiting a correlation with performance was localized in left temporal-parietal brain regions known to be associated with language processing. From our results, we conclude that in-task attenuation of individual alpha power is related to the essential mechanisms of the underlying cognitive processes, rather than merely to general phenomena like attention or vigilance. HighlightsO_LIComprehension of structurally complexed embedded sentences is correlated with individual alpha power attenuation during task but not with alpha power at rest. C_LIO_LIThese effects were localized in temporal-parietal brain regions known to be associated with language processing. C_LI Data availability statementAnonymized raw data will be made available upon request via email to the corresponding author provided the requesting researchers sign a formal data sharing agreement and cite this paper as origin of the data.

neuroscience↗

bioRxiv2021

Maturation of distinct neural components of the cognitive control network support early development of inhibitory control

Goal-directed behavior crucially relies on our capacity to suppress impulses and predominant behavioral responses. This ability, called inhibitory control, emerges in early childhood with marked improvements between 3 and 4 years. Here, we ask which brain structures are related to the emergence of this critical ability. Using a multimodal approach, we relate the pronounced behavioral improvements in different facets of 3-and 4-year-olds (N = 37, 20 female) inhibitory control to structural indices of maturation in the developing brain assessed with MRI. Our results show that cortical and subcortical structure of core regions in the adult cognitive control network, including the PFC, thalamus, and the inferior parietal cortices, are associated with early inhibitory functioning in preschool children. Probabilistic tractography revealed an association of frontoparietal (i.e., the superior longitudinal fascicle) and thalamocortical connections with early inhibitory control. Notably, these associations to brain structure were distinct for different facets of early inhibitory control, often referred to as motivational ( hot) and cognitive ( cold) inhibitory control. Our findings thus reveal the structural brain networks and connectivity related to the emergence of this core faculty of human cognition. Significance StatementThe capacity to suppress impulses and behavioral responses is crucial for goal-directed behavior. This ability, called inhibitory control, develops between the ages of 3 and 4 years. The factors behind this developmental milestone have been debated intensely for decades, however, the brain structure that underlies the emergence of inhibitory control in early childhood is largely unknown. Here, we relate the pronounced behavioral improvements in inhibitory control between 3 and 4 years with structural brain markers of grey matter and white matter maturation. Using a multimodal approach that combines analyses of cortical surface structure, subcortical structures, and white matter connectivity, our results reveal the structural brain networks and connectivity related to this core faculty of human cognition.

neuroscience↗

bioRxiv2021

Towards a causal role of Broca's area in language: A TMS-EEG study on syntactic prediction

Categorical predictions have been proposed as the key mechanism supporting the fast pace of syntactic composition in human language. Accordingly, grammar-based expectations facilitate the analysis of incoming syntactic information--e.g., hearing the determiner "the" enhances the prediction of a noun--which is then checked against a single or few other word categories. Previous functional neuroimaging studies point towards Brocas area in the left inferior frontal gyrus (IFG) as one fundamental cortical region involved in categorical prediction during on-line language processing. Causal evidence for this hypothesis is however still missing. In this study, we combined Electroencephalography (EEG) and Transcranial Magnetic Stimulation (TMS) to test whether Brocas area is functionally relevant in predictive mechanisms for language. Specifically, we transiently perturbed Brocas area during the categorical prediction phase in two-word constructions, while simultaneously measuring the Event-Related Potential (ERP) correlates of syntactic composition. We reasoned that if Brocas area is involved in predictive mechanisms for syntax, disruptive TMS during the processing of the first word (determiner/pronoun) would mitigate the difference in ERP responses for predicted and unpredicted categories when composing basic phrases and sentences. Contrary to our hypothesis, perturbation of Brocas area at the predictive stage did not affect the ERP correlates of basic composition. The correlation strength between the electrical field induced by TMS and the magnitude of the EEG response on the scalp further confirmed this pattern. We discuss the present results in light of an alternative account of the role of Brocas area in syntactic composition, namely the bottom-up integration of words into constituents.

neuroscience↗

bioRxiv2021

Chimpanzees use numerous flexible vocal sequences with more than two vocal units: A step towards language?

A major question in evolutionary science is how did language evolve? Syntax, as the core of language, combines meaning-bearing units (words) into hierarchical structures, thereby creating new meanings. Some other mammals and birds combine meaning-bearing vocalisations, but no documented examples exist of non-human animals combining more than two meaning-bearing vocalisations. Was the two-unit threshold only surpassed in the hominid lineage? Here, we examine the positional patterning of vocal sequences of chimpanzees. We analysed 4826 vocal utterances of 46 wild adult female and male chimpanzees. We found a flexible system with 390 multi-unit vocal sequences, some showing positional or transitional regularities. Two-unit pairs embedded in three-unit sequences predictably occurred either in head or tail positions, and co-occurred with specific other elements. The capacity to organise vocal output beyond the two-unit level may thus exist in species other than humans and could be viewed as an important evolutionary step towards language.

animal behavior and cognition↗

bioRxiv2020

Gradual development of non-adjacent dependency learning during early childhood

In order to become proficient native speakers, children have to learn the morpho-syntactic relations between distant elements in a sentence, so-called non-adjacent dependencies (NADs). Previous research suggests that NAD learning in children comprises different developmental stages, where until 2 years of age children are able to learn NADs associatively under passive listening conditions, while starting around the age of 3 to 4 years children fail to learn NADs during passive listening. To test whether the transition between these developmental stages occurs gradually, we tested childrens NAD learning in a foreign language using event-related potentials (ERPs). We found ERP evidence of NAD learning across the ages of 1, 2 and 3 years. The amplitude of the ERP effect indexing NAD learning, however, decreased with age. These findings might indicate a gradual transition in childrens ability to learn NADs associatively. Cognitively, this transition might be driven by childrens increasing knowledge of their native language, hindering NAD learning in novel contexts. Neuroanatomically, maturation of the prefrontal cortex might play a crucial role, promoting top-down learning, affecting bottom-up, associative learning. In sum, our study suggests that NAD learning under passive listening conditions undergoes a gradual transition between different developmental stages during early childhood. Research HighlightsO_LITransition between developmental stages of non-adjacent dependency (NAD) learning C_LIO_LIChildren between 1 and 3 years of age showed learning of NADs in a foreign language C_LIO_LIBrain responses revealed associative NAD learning, triggered by passive listening C_LIO_LIGradual decrease of the strength of associative non-adjacent dependency learning C_LI

neuroscience↗

bioRxiv2020

Increased Sensitivity and Signal-to-Noise Ratio in Diffusion-Weighted MRI using Multi-Echo Acquisitions

Post-mortem diffusion MRI (dMRI) enables acquisitions of structural imaging data with otherwise unreachable resolutions - at the expense of longer scanning times. These data are typically acquired using highly segmented image acquisition strategies, thereby resulting in an incomplete signal decay before the MRI encoding continues. Especially in dMRI, with low signal intensities and lengthy contrast encoding, such temporal inefficiency translates into reduced image quality and longer scanning times. This study introduces Multi Echo (ME) acquisitions to dMRI on a human MRI system - a time-efficient approach, which increases SNR (Signal-to-Noise Ratio) and reduces noise bias for dMRI images. The benefit of the introduced ME dMRI method was validated using numerical Monte Carlo simulations and showcased on a post-mortem brain of a wild chimpanzee. The proposed Maximum Likelihood Estimation echo combination results in an optimal SNR without detectable signal bias. The combined strategy comes at a small price in scanning time (here 30% additional) and leads to a substantial SNR increase (here up to 1.9x which is equivalent to 3.6 averages) and a general reduction of the noise bias.

neuroscience↗

bioRxiv2019

Seven-year-olds’ recollection of non-adjacent dependencies after overnight retention

Becoming a successful speaker depends on acquiring and learning grammatical dependencies between neighboring and non-neighboring linguistic elements (non-adjacent dependencies; NADs). Previous studies have demonstrated childrens and adults ability to distinguish NADs from NAD violations right after familiarization. However, demonstrating NAD recall after retention is crucial to demonstrate a lasting effect of NAD learning. We tested 7-year-olds NAD learning in a natural, non-native language on one day and NAD recall on the next day by means of event-related potentials (ERPs). Our results revealed ERPs with a more positive amplitude to NAD violations than correct NADs after familiarization on day one, but ERPs with a more negative amplitude to NAD violations on day two. This change from more positive to more negative ERPs to NAD violations possibly indicates that childrens representations of NADs changed during an overnight retention period, potentially associated with childrens NAD learning. Indeed, our descriptive analyses showed that both ERP patterns (i.e., day one: positive, day two: negative) were related to stronger behavioral improvement (i.e., more correct answers on day two compared to day one) in a grammaticality judgment task from day one to day two. We suggest these findings to indicate that children successfully built associative representations of NADs on day one and then strengthened these associations during overnight retention, revealing NAD recall on day two. The present results suggest that 7-year-olds readily track NADs in a natural, non-native language and are able to recall NADs after a retention period involving sleep, providing evidence of a lasting effect of NAD learning. HighlightsO_LI7-year-olds non-adjacent dependency learning in a foreign language tested C_LIO_LIChildren gave grammaticality judgments while electroencephalography was recorded C_LIO_LIBrain responses revealed childrens learning of non-adjacent dependencies C_LIO_LIBrain responses after overnight retention showed different polarity C_LIO_LIChildrens recall of dependencies after sleep associated with representation change C_LI

neuroscience↗