Biomedical subjects

Thomas F Münte

Publications and source records attributed to Thomas F Münte.

At least 55 records · Page 3Linked to original sources

PubMed2003

Recognition memory for unfamiliar faces does not differ for adult normal and dyslexic readers: an event-related brain potential study.

OBJECTIVE: Differences in recognition memory for unfamiliar faces between adult developmental dyslexic (n=12) and normal readers (n=12) were studied by means of event-related brain potentials. METHODS: Subjects performed a continuous face recognition task, in which 240 unfamiliar faces were presented on a computer screen, 100 of which were repetitions. For each face, subjects had to indicate whether it was presented before or not. Performance did not differ between normal and dyslexic readers. Old/repeated faces elicited more positive event-related potentials (ERPs) starting 250 ms poststimulus. These were analyzed in two time-windows encompassing the early (250-450 ms) and the late phase (450-750 ms) of the old/new effect. RESULTS: No group difference in amplitude or topography of the old/new effect emerged. However, ERPs for all faces were more positive for normal compared with those of dyslexic readers. CONCLUSIONS: These results show that a previously described recognition memory deficit for words in dyslexic readers is likely to be specific for verbal material.

Adult↗

PubMed2003

[Psychosomatic stress factors in compensated and decompensated tinnitus].

AIMS: In modern medical practice, chronic decompensated tinnitus is defined as a complex psychosomatic process in which mental and social factors are considered to have a determining effect on the patient's subjective response to the impairment of otological or other somatic functions attributed to tinnitus. What is still largely unknown is the interaction of the individual factors and their impact on the patient's ability to cope with tinnitus. The impact of psycho-social and somatic factors on the subjective experience of patients with compensated and decompensated tinnitus is evaluated. PATIENTS AND METHODS: 53 patients with chronic tinnitus were divided into two groups, compensated and decompensated, on the basis of their subjective experience of the disorder, established according to the tinnitus questionnaire published by Goebel and Hiller. Self-assessment instruments and a survey of symptoms of somatic stress disorders were used to compare the two groups in terms of differences in the patients' mental and psycho-social behaviour, in their strategies for coping with tinnitus and in the incidence of co-morbidity. RESULTS: The patients with decompensated tinnitus suffered from more pronounced mental and social disabilities, were more prone to depression and used less effective techniques to cope with their illness. The principal difference between the two groups, however, appeared to lie in a significantly higher degree of somatic multi-morbidity, where a particularly strong correlation was found between tinnitus and the incidence of cardiovascular diseases and hypacusis. 81 percent of the total sample of patients suffered from impaired hearing. Patients with decompensated tinnitus experienced greater communication difficulties as a result of their auditory impairment. CONCLUSIONS: In the diagnosis and therapy of tinnitus, in addition to psychic and psycho-social aspects greater attention ought to be paid to somatic factors, influencing the patient's ability to cope with the disorder.

Adult↗

PubMed2003

The influence of semantic and phonological factors on syntactic decisions: an event-related brain potential study.

During language production and comprehension, information about a word's syntactic properties is sometimes needed. While the decision about the grammatical gender of a word requires access to syntactic knowledge, it has also been hypothesized that semantic (i.e., biological gender) or phonological information (i.e., sound regularities) may influence this decision. Event-related potentials (ERPs) were measured while native speakers of German processed written words that were or were not semantically and/or phonologically marked for gender. Behavioral and ERP results showed that participants were faster in making a gender decision when words were semantically and/or phonologically gender marked than when this was not the case, although the phonological effects were less clear. In conclusion, our data provide evidence that even though participants performed a grammatical gender decision, this task can be influenced by semantic and phonological factors.

Adult↗

PubMed2003

Tourette syndrome and obsessive-compulsive disorder: event-related brain potentials show similar mechanisms [correction of mechansims] of frontal inhibition but dissimilar target evaluation processes.

OBJECTIVES: Tourette Syndrome (TS) and Obsessive-Compulsive Disorders (OCD) share many clinical similarities and show a strong comorbidity. Current theories view a frontal-striatal dysfunction as the underlying cause of many clinical aspects of both disorders. This study sought to investigate mechanisms of conceptual integration and attention in both disorders. We hypothesized that the processing of stimuli with interfering aspects would be altered in a similar way while attentional mechanisms could differ. METHODS: Event-related brain potentials (ERPs) were recorded in a modified STROOP-paradigm in groups of TS and OCD patients and in a control group. The paradigm involved the presentation of color words in a range of different colors. The subjects had to respond to words of matching word content and color and to ignore mismatching stimuli. RESULTS: Incongruent stimuli elicited a frontal negative component ("N450") which was enhanced in amplitude and prolonged in latency in both patient groups. Matching stimuli evoked enhanced N2 and P3b components representing target evaluation mechanisms. The OCD group alone displayed a larger P3b amplitude in comparison to both other groups. CONCLUSIONS: The data are interpreted to indicate that frontal inhibitory mechanisms are altered alike in TS and OCD. In contrast, only the OCD group showed evidence for aberrant target evaluation.

Adolescent↗

PubMed2003

Disturbed monitoring and response inhibition in patients with Gilles de la Tourette syndrome and co-morbid obsessive compulsive disorder.

OBJECTIVE: Fronto-striatal dysfunction has been discussed as underlying symptoms of Tourette syndrome (TS) with co-morbid Obsessive Compulsive Disorder (OCD). This suggests possible impairments of executive functions in this disorder, which were therefore targeted in the present study. METHODS: A comprehensive series of neuropsychological tests examining attention, memory and executive functions was performed in a group of 14 TS/OCD in co-occurrence with OCD patients and a matched control group. RESULTS: While attentional and memory mechanisms were not altered, TS/OCS patients showed deficits in executive functions predominantly in the areas of response inhibition and action monitoring. CONCLUSIONS: These findings provide further evidence for a substantial impairment of the frontal-striatal-thalamic-frontal circuit. We propose that the deficits in monitoring, error detection and response inhibition constitute the major impairment of TS/OCD patients in the cognitive domain.

Adult↗

PubMed2003

Specialization of the specialized: electrophysiological investigations in professional musicians.

Several event-related brain potential (ERP) studies examining the processing of auditory stimuli by professional musicians compared with non-musicians are reviewed. In the first study, musicians (string players) and non-musicians attended to one of two streams of auditory stimuli characterized by a specific pitch. Musicians showed a prolonged ERP attention effect, the late portion of which was more frontally distributed than was that of the non-musicians. In the second study, we investigated auditory spatial processing in conductors, pianists, and nonmusicians. Only the conductors showed behavioral selectivity of sound sources located in the peripheral auditory space. In addition, this group showed a negative/positive mismatch response for deviant stimuli occurring outside the focus of spatial attention. Finally, a group of drummers was compared to woodwind players and nonmusicians in a passive listening task. A real continuous drum sequence was manipulated so that some beats were anticipated by 80 ms. The drummers showed a mismatch response not only for the anticipated beats but also for the subsequent beats, suggesting a more complex representation of the temporal aspects stimulus sequence in this subject group. Together, these studies suggest qualitative differences of the neural correlates of auditory processing between musicians and non-musicians. Moreover, these differences appear to be shaped by the specific training of a musician.

Auditory Perception↗

PubMed2003

Implicit memory varies as a function of hypnotic electroencephalogram stage in surgical patients.

UNLABELLED: Previous studies have observed a correlation of implicit memory with certain electroencephalogram (EEG) measures during anesthesia. Here, we tested the relationship between hypnotic depth determined by computer system (Narcotrend(TM)) and implicit memory in anesthetized patients, assessed by a postoperative reading speed test. Thirty-two patients undergoing laparoscopic herniotomy and 30 age-matched volunteer controls were included the study. All patients received IV midazolam 2-3 mg followed by an induction dose of propofol and remifentanil. The anesthesia was maintained with propofol and remifentanil infusions and cisatracurium. Each patient was exposed to 2 of 4 stories, repeated 6 times. The first story was presented during light to moderate hypnotic EEG stages, and the second story was presented during deep hypnosis. Presentation of stories was balanced between patients and hypnotic stages. The controls listened to the two stories without receiving anesthesia. The reading speed for the previously presented stories and two new stories was measured approximately 7 h later with a computer program. No signs of inadequate anesthesia were observed, and no explicit memories of intraoperative events were revealed by a structured interview. No change of reading speed was observed for words presented during deep hypnotic stages. In contrast, an increased reading speed of 20 ms per word was found for content words (i.e., nouns, verbs, and adjectives), but not for function words (conjunctions, prepositions, and so on), presented during light to moderate hypnotic stages. Increased reading speed for semantically rich content words indicates that anesthetized patients are able to process acoustic information during light and moderate, but not deep, hypnosis. IMPLICATIONS: In this study, implicit memory was observed during general anesthesia at light to moderate, but not deep, hypnotic stages. Hypnotic stages were determined by a commercial electroencephalogram device, and implicit memory was measured by using a postoperative reading speed task. During lighter phases of anesthesia, patients should be protected against acoustic information that could negatively influence their postoperative outcome.

Adult↗

PubMed2002

Time course of error detection and correction in humans: neurophysiological evidence.

Using event-related brain potentials, the time course of error detection and correction was studied in healthy human subjects. A feedforward model of error correction was used to predict the timing properties of the error and corrective movements. Analysis of the multichannel recordings focused on (1) the error-related negativity (ERN) seen immediately after errors in response- and stimulus-locked averages and (2) on the lateralized readiness potential (LRP) reflecting motor preparation. Comparison of the onset and time course of the ERN and LRP components showed that the signs of corrective activity preceded the ERN. Thus, error correction was implemented before or at least in parallel with the appearance of the ERN component. Also, the amplitude of the ERN component was increased for errors, followed by fast corrective movements. The results are compatible with recent views considering the ERN component as the output of an evaluative system engaged in monitoring motor conflict.

Adult↗

PubMed2002

Morphological priming in Spanish verb forms: an ERP repetition priming study.

The ERP repetition priming paradigm has been shown to be sensitive to the processing differences between regular and irregular verb forms in English and German. The purpose of the present study is to extend this research to a language with a different inflectional system, Spanish. The design (delayed visual repetition priming) was adopted from our previous study on English, and the specific linguistic phenomena we examined are priming relations between different kinds of stem (or root) forms. There were two experimental conditions: In the first condition, the prime and the target shared the same stem form, e.g., "ando-andar" [I walk-to walk], whereas in the second condition, the prime contained a marked (alternated) stem, e.g., "duermo-dormir" [I sleep-to sleep]. A reduced N400 was found for unmarked (nonalternated) stems in the primed condition, whereas marked stems showed no such effect. Moreover, control conditions demonstrated that the surface form properties (i.e., the different degree of phonetic and orthographic overlap between primes and targets) do not explain the observed priming difference. The ERP priming effect for verb forms with unmarked stems in Spanish is parallel to that found for regularly inflected verb forms in English and German. We argue that effective priming is possible because prime target pairs such as "ando-andar" access the same lexical entry for their stems. By contrast, verb forms with alternated stems (e.g., "duermo") constitute separate lexical entries, and are therefore less powerful primes for their corresponding base forms.

Adult↗

PubMed2002

Brain potential and functional MRI evidence for how to handle two languages with one brain.

Bilingual individuals need effective mechanisms to prevent interference from one language while processing material in the other. Here we show, using event-related brain potentials and functional magnetic resonance imaging (fMRI), that words from the non-target language are rejected at an early stage before semantic analysis in bilinguals. Bilingual Spanish/Catalan and monolingual Spanish subjects were instructed to press a button when presented with words in one language, while ignoring words in the other language and pseudowords. The brain potentials of bilingual subjects in response to words of the non-target language were not sensitive to word frequency, indicating that the meaning of non-target words was not accessed in bilinguals. The fMRI activation patterns of bilinguals included a number of areas previously implicated in phonological and pseudoword processing, suggesting that bilinguals use an indirect phonological access route to the lexicon of the target language to avoid interference.

Adult↗

PubMed2002

Brains out of tune.

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Auditory Perceptual Disorders↗

PubMed2002

Excessive action monitoring in Tourette syndrome.

Tourette Syndrome (TS) has been related to hyperactive basal-ganglia thalamocortical pathways. This suggests that action monitoring might also be hyperactive. The present study used the event-related brain potential (ERP) technique to investigate this hypothesis. A simple "oddball" reaction time experiment was administered to a group of TS patients and a matched control group. In order to investigate variations in attentional allocation separate experimental runs were undertaken with target frequencies of 50% and 80%. The P3b component to targets was taken as an indicator of the target evaluation process and the response locked error-related negativity (ERN) served as an indicator of action monitoring. We hypothesized that the amplitudes of ERN and P3b would vary with respect to target frequency. The TS group would show an overall enhanced ERN but an unchanged P3b.ERN and P3b amplitudes were lower in the 80% target condition than in the 50% condition. In comparison with control subjects TS patients displayed an ERN of overall higher amplitude but with similar variations between target conditions. P3b amplitudes did not differ between groups. The data are interpreted to support the assumption of an abnormal action monitoring system in TS. A number of similarities to Obsessive-Compulsive Disorder are outlined and it is argued that the findings could be related to a hyperactive frontal-striatal-thalamic-frontal circuit.

Adolescent↗

PubMed2002

Electrophysiological estimates of the time course of semantic and phonological encoding during listening and naming.

Current psycholinguistic models suggest that we know what we want to say before we decide how we are going to say it: in other words, for speaking, word meaning is activated prior to information about syntax and phonology. Listening likely involves the reverse order of processes: phonological processing before meaning activation. We examined the relative time courses of phonological and semantic processing during language production and comprehension using event-related brain potentials (ERPs). Participants viewed a series of pictures (with the instruction to covertly name the depicted item), or heard a series of words, and made dual choice Go/noGo decisions based on each item's conceptual (whether the item was an animal or an object) and phonological features (whether the item's German name started with a vowel or a consonant). During picture naming, the N200 component (related to response inhibition) indicated that conceptual processing preceded phonological processing by about 170ms. During auditory word processing, on the other hand, the brain activity related to these two aspects of comprehension indicated some temporal overlap with the N200 to phonological processing preceding that to semantic processing by only about 85ms. In sum, the data are compatible with current psycholinguistic models of speech production and comprehension and argue for serial or widely spaced cascaded processing during production but more parallel processing of information during comprehension.

Adult↗

PubMed2002

Electrophysiological estimates of biological and syntactic gender violation during pronoun processing.

During comprehension, a personal pronoun (he, she, it) refers to a preceding referent (boy, girl, child). This co-reference could be established, among other ways, by using (i). conceptual/semantic information (biological gender agreement between the pronoun and its referent), (ii). syntactic information (syntactic gender agreement), or (iii). both. This event-related brain potential (ERP) study assesses this interplay of syntactic and semantic information. We focussed on the N400 component, related to semantic integration, and the SPS/P600 component, related to syntactic reanalysis. The study was conducted in German, because its rich syntactic gender system offers a means to dissociate between biological (MALE/FEMALE) and syntactic gender (masculine/feminine/neuter), especially in the case of diminutives (das(neuter) Bübchen(MALE) [the little boy]). German subjects read sentences in which a referent (Bübchen(MALE-neuter)/Bub(MALE-masculine) [boy]) was introduced. Later a personal pronoun was presented which either agreed with the referent in terms of syntactic gender, or in terms of biological gender, or both, or violated both agreements. Overall, results showed salient P600 effects for pronouns. This indicates that the establishment of reference involves syntactic reanalysis. Furthermore, we observed N400 effects in sentences with non-diminutives, but not with diminutives. This shows that conceptual/semantic integration is involved during non-diminutive but not during diminutive pronoun processing, or at least it could not be violated. The overall pattern of results supports the claim that for non-diminutives, both syntactic and conceptual information is used to establish co-reference, while for diminutives the process might be purely syntactically driven.

Adult↗

PubMed2002

Word order in sentence processing: an experimental study of verb placement in German.

We examine the question of whether the human comprehension device exhibits word-order preferences during on-line sentence comprehension. The focus is on the positioning of finite verbs and auxiliaries relative to subjects and objects in German. Results from three experiments (using self-paced reading and event-related brain potentials) show that native speakers of German prefer to process finite verbs in second position (i.e., immediately after the subject and before the object). We will account for this order preference in terms of the relative processing costs associated with SVfO and SOVf. Our finding that word-order preferences play an important role in the on-line comprehension of German sentences is compatible with results from previous studies on English and other languages.

Adult↗

PubMed2002

The musician's brain as a model of neuroplasticity.

Studies of experience-driven neuroplasticity at the behavioural, ensemble, cellular and molecular levels have shown that the structure and significance of the eliciting stimulus can determine the neural changes that result. Studying such effects in humans is difficult, but professional musicians represent an ideal model in which to investigate plastic changes in the human brain. There are two advantages to studying plasticity in musicians: the complexity of the eliciting stimulus music and the extent of their exposure to this stimulus. Here, we focus on the functional and anatomical differences that have been detected in musicians by modern neuroimaging methods.

Cerebral Cortex↗

PubMed2002

The effects of proprioceptive stimulation on cognitive processes in patients after traumatic brain injury.

OBJECTIVE: To investigate the hypothesis that proprioceptive stimulation may be effective in the treatment of brain injury, using neurophysiologic and neuropsychologic measures. DESIGN: Cohort analytic study. SETTING: Patients recovering from traumatic brain injury (TBI) in a neurologic rehabilitation hospital were examined. PARTICIPANTS: Eleven patients with TBI (Glasgow Coma Scale score > 3) and 11 healthy control subjects matched for age and education. INTERVENTIONS: Subjects were examined with the event-related potential (ERP) technique during a computerized choice-reaction-time task, in which they had to discriminate between even and odd digits. There were experimental runs with and without vibratory stimuli applied to the left forearm serving as proprioceptive stimulation. In addition, ERPs were recorded to vibratory stimuli without any additional task. MAIN OUTCOME MEASURES: Outcome measures included latencies and amplitudes of the P300 ERP component and of the late negative component. RESULTS: In the passive vibration condition, both groups showed the same ERP distribution. In the choice-reaction-time task, latencies and amplitudes of the P300 differed between the 2 groups. The patient group showed longer P300 latencies, which were shortened by vibratory stimuli. In contrast, the control subjects were not affected by vibratory stimuli. CONCLUSION: Our findings support the hypothesis that pathologic cognitive processes after TBI can be improved by proprioceptive stimulation. Muscle vibration has positive effects on pathologically slowed cognitive processes but not in healthy subjects.

Adult↗

PubMed2002

Disturbance of "extrinsic alertness" in Huntington's disease.

Neuropsychological deficits are a main feature of Huntington's disease (HD) with previous data suggesting involvement of attentional functions. Attention can be divided into several different dimensions: intensity, selectivity and supervisory attentional control. These different aspects of attention were investigated in a group of 13 patients with HD and 13 healthy matched control subjects. HD patients were impaired mostly for the intensity dimension: contrary to controls, and like other neurological patient groups, they were not able to speed up their reaction times when an auditory warning stimulus preceded a visual target which suggests a deficit in 'extrinsic alertness.' In addition less severe impairments were found in the dimensions selectivity and supervisory attentional control.

Adult↗