Biomedical subjects

Angela D Friederici

Publications and source records attributed to Angela D Friederici.

At least 19 recordsLinked to original sources

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

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

Prosody-assisted head-driven access to spoken German compounds.

Auditory processing of German 2-noun compound words was investigated with 328 participants in 4 experiments by monitoring semantic priming effects of the left constituents of the compound words. The authors demonstrated that there is no primacy of the left constituents in accessing auditorily presented German compound words in the mental lexicon. A clear priming effect of left constituents occurred only for compound words with a transparent right constituent that is the head of compound words in Germanic languages. The data suggest that the access to German compounds in the auditory domain involves 2 temporally overlapping routes: direct and decompositional. The prosodic structure (i.e., the duration) of the first morphemes of compound words appears to be a determining factor for activation of the decompositional route.

Adult↗

PubMed2003

The role of left inferior frontal and superior temporal cortex in sentence comprehension: localizing syntactic and semantic processes.

An event-related functional magnetic resonance imaging (fMRI) paradigm was used to specify those brain areas supporting the processing of sentence-level semantic and syntactic information. Hemodynamic responses were recorded while participants listened to correct, semantically incorrect and syntactically incorrect sentences. Both anomalous conditions recruited larger portions of the superior temporal region than correct sentences. Processing of semantic violations relied primarily on the mid-portion of the superior temporal region bilaterally and the insular cortex bilaterally, whereas processing of syntactic violations specifically involved the anterior portion of the left superior temporal gyrus, the left posterior frontal operculum adjacent to Broca's area and the putamen in the left basal ganglia. A comparison of the two anomalous conditions revealed higher levels of activation for the syntactic over the semantic condition in the left basal ganglia and for the semantic over the syntactic condition in the mid-portion of the superior temporal gyrus, bilaterally. These data indicate that both semantic and syntactic processes are supported by a temporo-frontal network with distinct areas specialized for semantic and syntactic processes.

Adult↗

PubMed2003

Syntactic comprehension in Parkinson's disease: investigating early automatic and late integrational processes using event-related brain potentials.

Parkinson's disease (PD) has been associated with a general impairment of procedures and with an impairment of syntactic procedures in particular. The present study investigated comprehension processes in PD using event-related brain potentials (ERPs). PD patients and controls listened to sentences that were either correct or syntactically or semantically incorrect. The language-related ERP component correlated with semantic processes (N400) was present in both groups. In the syntactic domain, early automatic processes (early negativity) appeared normal in PD, whereas late integrational processes (P600) were modulated by this disease. The present findings suggest that the basal ganglia primarily do not support early automatic syntactic processes during comprehension but rather support processes of syntactic integration.

Aged↗

PubMed2002

Spatial versus object feature processing in human auditory cortex: a magnetoencephalographic study.

The human visual system is divided into two pathways specialized for the processing of either objects or spatial locations. Neuroanatomical studies in monkeys have suggested that a similar specialization may also divide auditory cortex into two such pathways. We used the identical stimulus material in two experimental sessions in which subjects had to either identify auditory objects or their location. Magnetoencephalograms were recorded and M100 dipoles were fitted into individual brain models. In the right hemisphere, the processing of auditory spatial information lead to more lateral activations within the temporal plane while object identification lead to more medial activations. These findings suggest that the human auditory system processes object features and spatial features in distinct areas.

Acoustic Stimulation↗

PubMed2002

Exploring the activation of semantic and phonological codes during speech planning with event-related brain potentials.

We present a new technique for studying the activation of semantic and phonological codes in speech planning using event-related brain potentials (ERPs) that extend a well-established behavioral procedure from speech production research. It combines a delayed picture-naming task with a priming procedure. While participants prepared the production of a depicted object's name, they heard an auditory target word. If the prepared picture name and the target word were semantically or phonologically related, the ERP waveform to the target word tended less towards the negative when compared to an unrelated control. These effects were widely distributed. By contrast, if participants performed a nonlinguistic task on the depicted object (natural size judgment), the semantic effect was still obtained while the phonological effect disappeared. This suggests that the former effect indexes semantic activation involved in object processing while the latter effect indexes word-form activation specific to lexical processing. The data are discussed in the context of models of lexical access in speech production.

Acoustic Stimulation↗

PubMed2002

Neural manifestation of cognitive and precognitive mismatch detection in early infancy.

We recorded event-related potentials (ERPs) in 2-month-old infants in two different states of alertness: awake and asleep. Syllables varying in vowel duration (long vs short) were presented in an oddball paradigm, known to elicit a mismatch brain response. ERPs of both groups showed a mismatch response reflected in a positivity followed by a frontal negativity. While the positivity was present as a function of the stimulus type (present for long deviants only), the negativity varied as a function of the state of alertness (present for awake infants only). These data indicate a functional separation between precognitive and cognitive aspects of duration mismatch essential for the distinction between long and short vowels during early infancy.

Acoustic Stimulation↗

PubMed2002

Non-invasive regime for language lateralization in right- and left-handers by means of functional MRI and dichotic listening.

Language lateralization was assessed by two independent functional techniques, fMRI and a dichotic listening test (DLT), in an attempt to establish a reliable and non-invasive protocol of dominance determination. This should particularly address the high intraindividual variability of language lateralization and allow decision-making in individual cases. Functional MRI of word classification tasks showed robust language lateralization in 17 right-handers and 17 left-handers in terms of activation in the inferior frontal gyrus. The DLT was introduced as a complementary tool to MR mapping for language dominance assessment, providing information on perceptual language processing located in superior temporal cortices. The overall agreement of lateralization assessment between the two techniques was 97.1%. Conflicting results were found in one subject, and diverging indices in ten further subjects. Increasing age, non-familial sinistrality, and a non-dominant writing hand were identified as the main factors explaining the observed mismatch between the two techniques. This finding stresses the concept of an intrahemispheric distribution of language function that is obviously associated with certain behavioral characteristics.

Adult↗