Biomedical subjects

Angela D Friederici

Publications and source records attributed to Angela D Friederici.

At least 91 records · Page 5Linked to original sources

PubMed2004

Brain signatures of syntactic and semantic processes during children's language development.

Developmental aspects of language comprehension were investigated using event-related brain potentials. Children between the ages of 6 and 13 listened to passive sentences that were correct, semantically incorrect, or syntactically incorrect, and data in each condition were compared with those of adults. For semantic violations, adults demonstrated a negativity (N400), as did children, but the latency decreased with age. For syntactic violations, adults displayed an early left anterior negativity (ELAN) and a late centro-parietal positivity (P600). A syntactic negativity and a late positivity were also present for children between 7 and 13 years, again with latency decreasing with age. Six-year-olds, in contrast, did not demonstrate an ELAN effect, but a late, reduced P600 pattern for the syntactic violation condition. In the early time window, the 6-year-olds displayed a widely distributed negativity that was larger for the correct than for the syntactically incorrect condition. These data indicate that the neurophysiological basis for semantic processes during auditory sentence comprehension does not change dramatically between early childhood and adulthood. Syntactic processes for passive sentences appear to differ between early and late childhood, at least with respect to those processes reflected in the ELAN component. As there is evidence that the ELAN reflects highly automatic structure-building processes, we conclude that these processes are not yet established at age 7, but gradually develop toward adult-like processing during late childhood.

Acoustic Stimulation↗

PubMed2004

N400-like semantic incongruity effect in 19-month-olds: processing known words in picture contexts.

To understand mechanisms of early language acquisition, it is important to know whether the child's brain acts in an adult-like manner when processing words in meaningful contexts. The N400, a negative component in the eventrelated potential (ERP) of adults, is a sensitive index of semantic processing reflecting neural mechanisms of semantic integration into context. In the present study, we investigated whether the mechanisms indexed by the N400 are already working during early language acquisition. While 19-month-olds were looking at sequentially presented pictures, they were acoustically presented with words that were either congruous or incongruous to the picture content. The ERP averaged across the group of 55 children revealed an N400-like semantic incongruity effect in addition to an early phonological-lexical priming effect. The results suggest that both lexical expectations facilitating early phonological processing and mechanisms of semantic priming facilitating integration into semantic context are already present in 19-month-olds. The child's specific comprehension abilities are reflected in strength, latency, and hemispheric differences of the semantic incongruity effect. Spatio-temporal differences in that effect, thus, indicate changes in the organization of brain activity correlated with the child's behavioral development.

Acoustic Stimulation↗

PubMed2004

Neural correlates of syntactic ambiguity in sentence comprehension for low and high span readers.

Syntactically ambiguous sentences have been found to be difficult to process, in particular, for individuals with low working memory capacity. The current study used fMRI to investigate the neural basis of this effect in the processing of written sentences. Participants with high and low working memory capacity read sentences with either a short or long region of temporary syntactic ambiguity while being scanned. A distributed left-dominant network in the peri-sylvian region was identified to support sentence processing in the critical region of the sentence. Within this network, only the superior portion of Broca's area (BA 44) and a parietal region showed an activation increase as a function of the length of the syntactically ambiguous region in the sentence. Furthermore, it was only the BA 44 region that exhibited an interaction of working memory span, length of the syntactic ambiguity, and sentence complexity. In this area, the activation increase for syntactically more complex sentences became only significant under longer regions of ambiguity, and for low span readers only. This finding suggests that neural activity in BA 44 increases during sentence comprehension when processing demands increase, be it due to syntactic processing demands or by an interaction with the individually available working memory capacity.

Adult↗

PubMed2004

ERPs reflect lexical identification in word fragment priming.

Behavioral evidence suggests that spoken word recognition involves the temporary activation of multiple entries in a listener's mental lexicon. This phenomenon can be demonstrated in cross-modal word fragment priming (CMWP). In CMWP, an auditory word fragment (prime) is immediately followed by a visual word or pseudoword (target). Experiment 1 investigated ERPs for targets presented in this paradigm. Half of the targets were congruent with the prime (e.g., in the prime-target pair: AM-AMBOSS [anvil]), half were not (e.g., AM-PENSUM [pensum]). Lexical entries of the congruent targets should receive activation from the prime. Thus, lexical identification of these targets should be facilitated. An ERP effect named P350, two frontal negative ERP deflections, and the N400 were sensitive to prime-target congruency. In Experiment 2, the relation of the formerly observed ERP effects to processes in a modality-independent mental lexicon was investigated by presenting primes visually. Only the P350 effect could be replicated across different fragment lengths. Therefore, the P350 is discussed as a correlate of lexical identification in a modality-independent mental lexicon.

Adolescent↗

PubMed2003

Processing tonal modulations: an ERP study.

A common stylistic element of Western tonal music is the change of key within a musical sequence (known as modulation in musical terms). The aim of the present study was to investigate neural correlates of the cognitive processing of modulations with event-related brain potentials. Participants listened to sequences of chords that were infrequently modulating. Modulating chords elicited distinct effects in the event-related brain potentials: an early right anterior negativity reflecting the processing of a violation of musical regularities and a late frontal negativity taken to reflect processes of harmonic integration. Additionally, modulations elicited a tonic negative potential suggested to reflect cognitive processes characteristic for the processing of tonal modulations, namely, the restructuring of the "hierarchy of harmonic stability" (which specifies musical expectations), presumably entailing working memory operations. Participants were "nonmusicians"; results thus support the hypothesis that nonmusicians have a sophisticated (implicit) knowledge about musical regularities.

Acoustic Stimulation↗

PubMed2003

Working memory and lexical ambiguity resolution as revealed by ERPs: a difficult case for activation theories.

This series of three event-related potential experiments explored the issue of whether the underlying mechanism of working memory (WM) supporting language processing is inhibitory or activational in nature. These different cognitive mechanisms have been proposed to explain the more efficient processing of subjects with a high WM span compared to those with a low WM span. Participants with high and low WM span were presented with sentences containing a homonym followed three words later by a nominal disambiguation cue and a final disambiguation using a verb. At the position of the disambiguation cue, inhibitory or activational WM mechanisms predict contrasting results. When activation is the underlying mechanism for efficient processing, the prediction is that high memory span persons activate both meanings of the homonym equally in WM, whereas low memory span persons only have one meaning present. When inhibition is the underlying mechanism, the predictions are the reverse. The ERP data, in particular, the variations of the meaning related N400 component, showed clear evidence for inhibition as the underlying cognitive mechanism in high-span readers. For low-span participants the cueing towards the dominant or the subordinate meaning elicited an equivalently large N400 component suggesting that both meanings are active in WM. In high-span subjects, the dominant disambiguation cue elicited a smaller N400 than the subordinate one, indicating that for these subjects particularly the dominant meaning is active. The experiments showed that inhibitory processes are probably underlying WM used during language comprehension in high-span subjects. Moreover, they demonstrate that these subjects can use their inhibition in a more flexible manner than low-span subjects. The effects that these processing differences have on the efficiency of language parsing are discussed.

Adult↗

PubMed2003

Children processing music: electric brain responses reveal musical competence and gender differences.

Numerous studies investigated physiological correlates of the processing of musical information in adults. How these correlates develop during childhood is poorly understood. In the present study, we measured event-related electric brain potentials elicited in 5- and 9-year-old children while they listened to (major-minor tonal) music. Stimuli were chord sequences, infrequently containing harmonically inappropriate chords. Our results demonstrate that the degree of (in)appropriateness of the chords modified the brain responses in both groups according to music-theoretical principles. This suggests that already 5-year-old children process music according to a well-established cognitive representation of the major-minor tonal system and according to music-syntactic regularities. Moreover, we show that, in contrast to adults, an early negative brain response was left predominant in boys, whereas it was bilateral in girls, indicating a gender difference in children processing music, and revealing that children process music with a hemispheric weighting different from that of adults. Because children process, in contrast to adults, music in the same hemispheres as they process language, results indicate that children process music and language more similarly than adults. This finding might support the notion of a common origin of music and language in the human brain, and concurs with findings that demonstrate the importance of musical features of speech for the acquisition of language.

Acoustic Stimulation↗

PubMed2003

Electric brain responses reveal gender differences in music processing.

The present study investigates gender differences in the functional organization of the brain for music processing. In the language domain, males appear to have greater left hemisphere control than females. Despite some overlap of neural structures and processes for the perception of music and language, gender differences of musical functions have so far not been reported. Data sets of three previous music experiments with event-related brain potentials (ERPs) were pooled and re-analyzed. Results demonstrate that an electrophysiological correlate of music-syntactic processing (ERAN, or music-syntactic MMN) is generated bilaterally in females, and with right hemispheric predominance in males. The present findings indicate that gender differences for the analysis of auditory information are not restricted to processes in the linguistic domain such as syntax, semantics, and phonology.

Acoustic Stimulation↗

PubMed2003

Talker's voice and gender stereotype in human auditory sentence processing--evidence from event-related brain potentials.

The present study investigated the influence of implicit speaker information on the sentence interpretation. We auditorily presented sentences that comprised of either stereotypically male or stereotypically female self-referent utterances. In the congruent conditions, these utterances were produced by speakers whose gender matched the semantic content. In the incongruent condition, stereotypically male utterances were produced by female speakers and vice versa. The event-related brain potentials (ERP) of 32 listeners exhibited a late positivity (P600) for the incongruent condition. No significant differences were observed between male and female listeners. In the absence of any ERP effect in the earlier time range, it was concluded that the access of the semantic information as such is independent of the speaker's voice, but that speaker property, semantic content and stereotypical knowledge are integrated in a later processing stage.

Adult↗

PubMed2003

Dissociation of human and computer voices in the brain: evidence for a preattentive gestalt-like perception.

We investigated the early ("preattentive") cortical processing of voice information, using the so-called "mismatch response". This brain potential allows inferences to be made about the sensory short-term store. Most importantly, the mismatch potential also provides information about the organization of long-term memory traces in the auditory system. Such traces have reliably been reported for phonemes. However, it is unclear whether they also exist for human voice information. To explore this issue, 10 healthy subjects were presented with a single word stimulus uttered by voices of different prototypicality (natural, manipulated, synthetic) in a mismatch experiment (stimulus duration 380 msec, onset-to-onset interval 900 msec). The event-related magnetic fields were recorded by a 148-channel whole-head magnetometer and a source current density modeling of the magnetic field data was performed using a minimum-norm estimate. Each deviating voice signal in a series of standard-voice stimuli evoked a mismatch response that was localized in temporal brain regions bilaterally. Increased mismatch related magnetic flux was observed in response to decreased prototypicality of a presented voice signal, but did not correspond to the acoustic similarity of standard voice and deviant voices. We, therefore, conclude that the mismatch activation predominantly reflects the ecological validity of the voice signals. We further demonstrate that the findings cannot be explained by mere acoustic feature processing, but rather point towards a holistic mapping of the incoming voice signal onto long-term representations in the auditory memory.

Acoustic Stimulation↗

PubMed2003

The brain basis of syntactic processes: functional imaging and lesion studies.

Language comprehension can be subdivided into three processing steps: initial structure building, semantic integration, and late syntactic integration. The two syntactic processing phases are correlated with two distinct components in the event-related brain potential, namely an early left anterior negativity (ELAN) and a late centroparietal positivity (P600). Moreover, ERP findings from healthy adults suggest that early structure-building processes as reflected by the ELAN are independent of semantic processes. fMRI results have revealed that semantic and syntactic processes are supported by separable temporofrontal networks, with the syntactic processes involving the left superior temporal gyrus (STG), the left frontal operculum, and the basal ganglia (BG) in particular. MEG data from healthy adults have indicated that the left anterior temporal region and the left inferior frontal region subserve the early structure building processes. ERP data from patients with lesions in the left anterior temporal region and from patients with lesions in the left inferior frontal gyrus support this view, as these patients do not demonstrate an ELAN, although they do demonstrate a P600. Further results from patients with BG dysfunction suggest that parts of this subcortical structure are involved in late syntactic integrational processes. The data from the different experiments lead to the notion of separable brain systems responsible for early and late syntactic processes, with the former being subserved by the inferior frontal gyrus and the anterior STG and the latter being supported by the BG and more posterior portions of the STG.

Adult↗

PubMed2003

On the lateralization of emotional prosody: an event-related functional MR investigation.

In order to investigate the lateralization of emotional speech we recorded the brain responses to three emotional intonations in two conditions, i.e., "normal" speech and "prosodic" speech (i.e., speech with no linguistic meaning, but retaining the 'slow prosodic modulations' of speech). Participants listened to semantically neutral sentences spoken with a positive, neutral, or negative intonation in both conditions and judged how positive, negative, or neutral the intonation was on a five-point scale. Core peri-sylvian language areas, as well as some frontal and subcortical areas were activated bilaterally in the normal speech condition. In contrast, a bilateral fronto-opercular region was active when participants listened to prosodic speech. Positive and negative intonations elicited a bilateral fronto-temporal and subcortical pattern in the normal speech condition, and more frontal activation in the prosodic speech condition. The current results call into question an exclusive right hemisphere lateralization of emotional prosody and expand patient data on the functional role of the basal ganglia during the perception of emotional prosody.

Adult↗

PubMed2003

The brain generates its own sentence melody: a Gestalt phenomenon in speech perception.

Brain processes underlying spoken language comprehension comprise auditory encoding, prosodic analysis and linguistic evaluation. Auditory encoding usually activates both hemispheres while language-specific stages are lateralized: analysis of prosodic cues are right-lateralized while linguistic evaluation is left-lateralized. Here, we investigated to what extent the absence of prosodic information influences lateralization. MEG brain-responses indicated that syntactic violations lead to early bi-lateral brain responses for syntax violations. When the pitch of sentences was flattened to diminish prosodic cues, the brain's syntax response was lateralized to the right hemisphere, indicating that the missing pitch was generated automatically by the brain when it was absent. This represents a Gestalt phenomenon, since we perceive more than is actually presented.

Adult↗

PubMed2003

Intersentential syntactic context effects on comprehension: the role of working memory.

The study investigated the influence of a syntactically biasing context sentence on the processing of syntactically complex object-first relative clauses and even more complex object-first complement clauses in readers with individual differences in working memory. Behavioral as well as brain responses (event-related potentials, ERPs) were recorded from two groups of participants with either a high or a low working memory span. The behavioral data taken from a post-sentence comprehension question task indicate an intersentential syntactic contextual influence on the comprehension of object-first relative clauses for low span readers, but not for high span readers. The on-line ERP measures taken at the disambiguating item revealed for the high span readers a main effect of structure (subject- versus object-first) i.e., a P600, independent of context. Low span readers, in contrast, did not show any P600 structure effect. Thus, the combined data indicate a differential context effect on sentence comprehension in low and high span readers. High span readers parse the incoming information independent of intersentential context, whereas low span readers use the intersentential context off-line.

Adult↗

PubMed2003

Interactions of the hippocampal system and the prefrontal cortex in learning language-like rules.

One of the most influential views on the hippocampal function suggests that this brain region is critically involved in relational memory processing, that is, binding converging inputs to mediate the representation of relationships among the constituents of episodes. It has been proposed that this binding is automatic and obligatory during learning and remembering In addition, neuroimaging studies have highlighted the importance of the prefrontal cortex, in learning, memory, and language processing. However, the posited importance of hippocampal-prefrontal interaction remains to be empirically tested. In the present study we used functional magnetic resonance imaging to examine in detail this interaction by assessing learning-related changes in hemodynamic activity during artificial language acquisition. It has been shown previously that artificial grammar systems might be learned by evaluating pattern-based relations in word sequences and generalizing beyond specific word order, that is, rule abstraction. During scanning, participants learned an artificial language whose miniature grammar meets the universal principles of a natural language. Increased proficiency level of the artificial language is associated with decreased left hippocampal activity. In contrast, we observed an increased recruitment of the left inferior frontal gyrus (Broca's area), a region that contributes to syntax processing in natural language. The present results, therefore, indicate a learning-related change in brain circuitry underlying relational processes of language learning, with a transition from a similarity-based learning system in the medial temporal lobes to a language-related processing system in the left prefrontal cortex.

Adult↗

PubMed2003

Distinct brain representations for early and late learned words.

Recently there has been a renewed interest in cognitive psychology on the effects of the age of word acquisition (AoA) on lexical processing. In particular, it is currently unclear whether AoA or word frequency are better predictors of word recognition. To date no study has investigated the neural bases of the AoA effect or attempted to dissociate it from word frequency. We report a visual and an auditory event-related fMRI experiment investigating the influence of AoA and word frequency on neural activity, and show that AoA modulates brain areas that are not influenced by word frequency. The precuneus was activated for early learned words across auditory and visual presentation modalities. Additional activity in the auditory cortex was observed specifically for the reading of early acquired words. Late learned words, in contrast, led to a selective activation increase in lateral inferior frontal areas. These findings support models that suggest that early and late learned words are represented differently in the brain. They further allow to specify the nature of the representational differences, namely that early learned words are represented in the brain in a more sensory manner than late learned words.

Adolescent↗

PubMed2003

Why the P600 is not just a P300: the role of the basal ganglia.

One of the important issues in event-related brain potential research is whether the language-related P600 and the P300 oddball effect are distinct components or not. We addressed this question by testing 14 aphasic patients, half of them with lesions including the basal ganglia and half of them with temporo-parietal lesions, in both an auditory oddball task and an experiment with auditory presented verb inflection violations. Whereas both patient groups displayed a clear P300 effect in the oddball experiment, only the group with temporo-parietal lesions showed a P600 in the language experiment. These data indicate that the basal ganglia seem to play a crucial role in the modulation of the P600, but not of the P300 component.

Aphasia↗

PubMed2003

Syntactic language processing: ERP lesion data on the role of the basal ganglia.

The role of the basal ganglia in syntactic language processing was investigated with event-related brain potentials in fourteen neurologically impaired patients. Seven of these patients had basal ganglia lesions while 7 other patients primarily had lesions of the left temporo-parietal region excluding the basal ganglia. All patients listened to sentences that were either correct or included a verb argument structure violation. In previous experiments this type of violation elicited a biphasic pattern of an N400-P600 complex in young healthy participants. While the N400 may result from incorrect semantic-thematic role assignment, the P600 reflects the fact that verb information does not license the syntactic structure at present. Results of the patient experiment revealed a double dissociation: patients with left temporo-parietal lesions only show a P600, whereas patients with lesions of the basal ganglia showed no P600, but a negativity with extended duration that resembled an N400. The latter pattern not only confirms previous reports that the basal ganglia modulate the P600 but extends these results by showing that the N400 as a late semantic-thematic integration process appears partially modulated by the basal ganglia.

Adult↗