Biomedical subjects

Pienie Zwitserlood

Publications and source records attributed to Pienie Zwitserlood.

13 recordsLinked to original sources

PubMed2006

Nice wor_ if you can get the wor_: subliminal semantic and form priming in fragment completion.

Two experiments investigated subliminal semantic and form priming in a word-completion task. Visual gap-words with a dominant and a subordinate solution were preceded by form-related or by semantically related words, which were briefly presented and sandwich-masked. Priming of the subordinate solution was assessed in Experiment 1, relative to a neutral condition. Both solutions were primed in Experiment 2. In the absence of conscious prime recognition, both semantic and form primes reliably increased the probability with which the primed solution was given. With our variant of fragment-completion, response priming can be ruled out as explanation. Moreover, effects were already present at first presentation, excluding an interpretation in terms of partial awareness due to massive repetition. The data demonstrate automatic activation at both form and semantic levels in the absence of conscious awareness.

Adult↗

PubMed2006

Describing scenes hardly seen.

Knowledge about scene categories, the so-called gist, can be extracted very rapidly, while recognition and naming of individual scene objects is a more effortful process. We investigate this phenomenon by presenting action scenes involving two actors for durations varying between 100 and 300 ms. Incoherence was created by mirroring individual scene actors. Upon masked presentation participants had to report content, actors and objects and to indicate whether the scene was meaningful or not. Scene coherence was judged correctly at all presentation durations. Actors were correctly identified in about one-third of the cases even with presentation durations of 100 ms, and identification rate increased up to 80% with longer durations. Identification depended on scene coherence, on the position of agents in the scene, and on the position of actors relative to the fixation cross. These interdependencies of scene and object perception indicate that the visual system seems to be very sensitive to meaningful interactions of living entities. A series of fixations is not necessary to identify actors of a scene.

Attention↗

PubMed2006

Effects of personal familiarity on early neuromagnetic correlates of face perception.

This study investigated effects of familiarity and orientation on face processing by means of magnetoencephalography. Participants were presented with photographs of personally familiar, famous and unfamiliar faces in both upright and inverted orientation. They had to decide whether faces were familiar by means of manual yes/no responses. Independent of orientation, we observed a clear modulation of the M170 by familiarity, with personally familiar faces evoking larger amplitudes than unknown faces. The M170 was also sensitive to orientation, with larger amplitudes for inverted than upright faces. Moreover, the M170 exhibited larger amplitudes over the right than over the left hemisphere, but this asymmetry was present for upright faces only. The present data suggest that at least for personally familiar faces, neural correlates of identification start no later than approximately 170 ms, and underline a special role of the right hemisphere for faces in their typical upright orientation.

Adult↗

PubMed2005

Pre-attentive detection of syntactic and semantic errors.

This magnetoencephalographic study tested whether magnetic fields evoked by syntactic and semantic errors differ in their time course and magnitude from fields evoked by phonemic differences. An oddball design, using German sentences with embedded critical words was applied: The error condition (with the standard word RASEN, lawn, in 70% of the trials, and the syntactic and semantic errors ROSEN, roses and RIESEN, giant as deviants) was compared with a neutral, correct phonemic condition. Mismatch responses were significantly larger for syntactic and semantic errors as compared to mere phonemic deviations. The semantic error elicited higher mismatch responses than the syntactic error. This error-sensitive component is interpreted as a very early detector for semantic and syntactic errors.

Attention↗

PubMed2005

Anticipating upcoming words in discourse: evidence from ERPs and reading times.

The authors examined whether people can use their knowledge of the wider discourse rapidly enough to anticipate specific upcoming words as a sentence is unfolding. In an event-related brain potential (ERP) experiment, subjects heard Dutch stories that supported the prediction of a specific noun. To probe whether this noun was anticipated at a preceding indefinite article, stories were continued with a gender-marked adjective whose suffix mismatched the upcoming noun's syntactic gender. Prediction-inconsistent adjectives elicited a differential ERP effect, which disappeared in a no-discourse control experiment. Furthermore, in self-paced reading, prediction-inconsistent adjectives slowed readers down before the noun. These findings suggest that people can indeed predict upcoming words in fluent discourse and, moreover, that these predicted words can immediately begin to participate in incremental parsing operations.

Adolescent↗

PubMed2004

Levodopa: faster and better word learning in normal humans.

Dopamine is a potent modulator of learning and has been implicated in the encoding of stimulus salience. Repetition, however, as required for the acquisition and reacquisition of sensorimotor or cognitive skills (e.g., in aphasia therapy), decreases salience. We here tested whether increasing brain levels of dopamine during repetitive training improves learning success. Forty healthy humans took 100mg of the dopamine precursor levodopa or placebo daily for 5 days in a randomized double-blind and parallel-group design. Ninety minutes later on each day, subjects were trained on an artificial vocabulary using a high-frequency repetitive approach. Levodopa significantly enhanced the speed, overall success, and long-term retention of novel word learning in a dose-dependent manner. These findings indicate new ways to potentiate learning in a variety of domains if conventional training alone fails.

Adult↗

PubMed2004

D-amphetamine boosts language learning independent of its cardiovascular and motor arousing effects.

D-Amphetamine (AMPH) was effective in a number of studies on motor and language recovery after stroke, but given safety concerns, its general use after stroke is still debated. Most stroke patients are excluded from treatment because of a significant risk of cardiovascular dysregulation. AMPH acts on multiple transmitter systems, and mainly the noradrenergic actions are related to the cardiovascular effects. If AMPH's cardiovascular and arousal effects were correlated with its plasticity-enhancing effects in humans, this would imply that desired and undesired effects are inevitably tied. If not, improved cerebral reorganization may not be mediated by AMPH's arousing effects and could be achieved with substances lacking the undesired cardiovascular effects. As a model for language recovery after stroke, we used a prospective, randomized, double-blind, placebo-controlled design and taught 40 healthy male subjects an artificial vocabulary of 50 concrete nouns over the course of five consecutive training days (high-frequency training). The associative learning principle involved higher co-occurrences of 'correct' picture-pseudoword pairings as compared to 'incorrect' pairings. Subjects received either AMPH (0.25 mg/kg) or placebo 90 min prior to training on each day. Novel word learning was significantly faster and better in the AMPH as compared to the placebo group. Increased learning success was maintained 1 month post-training. No correlation was found between training success and drug-induced increases in blood pressure, heart rate, or a facilitation of simple motor reaction time. Our data show that AMPH's plasticity-enhancing effect in humans is not related to its cardiovascular arousal. This suggests that the beneficial effects in stroke patients could also be obtained by less cardiovascular active drugs.

Adult↗

PubMed2003

When and how do listeners relate a sentence to the wider discourse? Evidence from the N400 effect.

In two ERP experiments, we assessed the impact of discourse-level information on the processing of an unfolding spoken sentence. Subjects listened to sentences like Jane told her brother that he was exceptionally quick/slow, designed such that the alternative critical words were equally acceptable within the local sentence context. In Experiment 1, these sentences were embedded in a discourse that rendered one of the critical words anomalous (e.g. because Jane's brother had in fact done something very quickly). Relative to the coherent alternative, these discourse-anomalous words elicited a standard N400 effect that started at 150-200 ms after acoustic word onset. Furthermore, when the same sentences were heard in isolation in Experiment 2, the N400 effect disappeared. The results demonstrate that our listeners related the unfolding spoken words to the wider discourse extremely rapidly, after having heard the first two or three phonemes only, and in many cases well before the end of the word. In addition, the identical nature of discourse- and sentence-dependent N400 effects suggests that from the perspective of the word-elicited comprehension process indexed by the N400, the interpretive context delineated by a single unfolding sentence and a larger discourse is functionally identical.

Adolescent↗

PubMed2003

Event-related brain potentials reflect discourse-referential ambiguity in spoken language comprehension.

In two experiments, we explored the use of event-related brain potentials to selectively track the processes that establish reference during spoken language comprehension. Subjects listened to stories in which a particular noun phrase like "the girl" either uniquely referred to a single referent mentioned in the earlier discourse, or ambiguously referred to two equally suitable referents. Referentially ambiguous nouns ("the girl" with two girls introduced in the discourse context) elicited a frontally dominant and sustained negative shift in brain potentials, emerging within 300-400 ms after acoustic noun onset. The early onset of this effect reveals that reference to a discourse entity can be established very rapidly. Its morphology and distribution suggest that at least some of the processing consequences of referential ambiguity may involve an increased demand on memory resources. Furthermore, because this referentially induced ERP effect is very different from that of well-known ERP effects associated with the semantic (N400) and syntactic (e.g., P600/SPS) aspects of language comprehension, it suggests that ERPs can be used to selectively keep track of three major processes involved in the comprehension of an unfolding piece of discourse.

Adult↗

PubMedDate not supplied

Where and how morphologically complex words interplay with naming pictures.

Two picture-word experiments are reported in which a delay of 7 to 10 was introduced between distractor and picture. Distractor words were either derived words (Experiment 1) or compounds (Experiment 2), morphologically related to the picture name. In both experiments, the position of morphological overlap between distractor (e.g., rosebud vs tea-rose) and picture name (rose) was manipulated. Clear facilitation of picture naming latencies was obtained when pictures were paired with morphological distractors, and effects were independent of distractor type and position of overlap. The results are evaluated against "full listing" and "decomposition" approaches of morphological representation.

Humans↗

PubMedDate not supplied

The impact of semantic transparency of morphologically complex words on picture naming.

We examined the contribution of semantic similarity to morphological priming effects, using the immediate (Exp. 1 and 3) and the delayed variant (Exp. 2) of picture-word interference. Distractor words were either compounds morphologically related to the picture name, but differing with respect to their semantic transparency (hummingbird, jailbird (Exp. 1); butterfly, butter dish (Exp. 3)), or form-related non-compound words (e.g., trombone). All three experiments revealed strong facilitation of picture naming due to morphologically related distractors. Form-related distractors facilitated picture naming in the immediate variant only, and to a lesser degree than compounds. Interestingly, the size of the morphemic effect was almost identical for semantically transparent and opaque complex words, which suggests that they share morphemic representations. These results suggest that morphological complexity in speech production is coded at the level of form representations, independent of semantic transparency.

Humans↗

PubMedDate not supplied

Sublexical and morphological information in speech processing.

Three experiments investigated the impact of syllabic boundary information and of morphological structure on performance in a sequence-monitoring task. In sequence monitoring, participants detect pre-specified sequences of phonemes in spoken carrier words. Sequences corresponded to the first syllable of the carrier word, to its first morpheme, or simultaneously to both. The data from Experiments 1 and 2, using different variants of the monitoring task, showed a strong impact of syllable boundary cues on monitoring latencies. An effect of morphological match between targets and carrier words was also evident. Experiment 3, in which parts of the spoken carrier words were cross-spliced, revealed that syllabic boundary information takes precedence over morphological information. The results are in line with an early process of speech processing, in which syllabic cues are used to aid lexical access. The morphological effect is better understood as a later, probably lexical, contribution of morphological decomposition to monitoring performance.

Adult↗

PubMedDate not supplied

Plasticity of the human auditory cortex induced by discrimination learning of non-native, mora-timed contrasts of the Japanese language.

In this magnetoencephalographic (MEG) study, we examined with high temporal resolution the traces of learning in the speech-dominant left-hemispheric auditory cortex as a function of newly trained mora-timing. In Japanese, the "mora" is a temporal unit that divides words into almost isochronous segments (e.g., na-ka-mu-ra and to-o-kyo-o each comprises four mora). Changes in the brain responses of a group of German and Japanese subjects to differences in the mora structure of Japanese words were compared. German subjects performed a discrimination training in 10 sessions of 1.5 h each day. They learned to discriminate Japanese pairs of words (in a consonant, anni-ani; and a vowel, kiyo-kyo, condition), where the second word was shortened by one mora in eight steps of 15 msec each. A significant increase in learning performance, as reflected by behavioral measures, was observed, accompanied by a significant increase of the amplitude of the Mismatch Negativity Field (MMF). The German subjects' hit rate for detecting durational deviants increased by up to 35%. Reaction times and MMF latencies decreased significantly across training sessions. Japanese subjects showed a more sensitive MMF to smaller differences. Thus, even in young adults, perceptual learning of non-native mora-timing occurs rapidly and deeply. The enhanced behavioral and neurophysiological sensitivity found after training indicates a strong relationship between learning and (plastic) changes in the cortical substrate.

Adult↗