Voxel-based morphometry (VBM) has demonstrated structural brain changes between patients with Major Depressive Disorder (MDD) and healthy individuals. The initial response to antidepressants is crucial to predict prognosis in the treatment of MDD. The aim of the present study was to investigate gray matter abnormalities predicting antidepressant responsiveness and the relationships between volumetric differences and clinical/cognitive traits in MDD patients.
Tourette syndrome (TS) is a neurodevelopmental disorder characterized by motor and vocal tics. Tics are repetitive and uncontrolled behaviours that have been associated with basal ganglia dysfunction. We investigated saccadic eye movements in a group of young people with TS but without co-morbid ADHD. Participants performed two tasks. One required them to perform only pro-saccade responses (pure pro-saccade task). The other involved shifting, unpredictably, between executing pro- and anti-saccades (mixed saccade task). We show that in the mixing saccade task, the TS group makes significantly fewer errors than an age-matched control group, while responding equally fast. By contrast, on the pure pro-saccade task, the TS group were shown to be significantly slower to initiate and to complete the saccades (longer movement duration and decreased peak velocity) than controls, while movement amplitude and direction accuracy were not different. These findings demonstrate enhanced shifting ability despite slower reflexive responding in TS and are discussed with respect to a disorder-related adaptation for increased cognitive regulation of behaviour.
The principal purpose of this study was to examine whether event-related potential (ERP) waveform amplitudes at around 200 ms are affected by first-syllable frequency. Another purpose of this study was to investigate whether the source of the amplitude at around 200 ms is phonological syllable frequency or orthographic syllable frequency. The phonological first-syllable frequency and the orthographic first-syllable frequency of Korean pseudo-words were manipulated, and ERPs were collected during a go/no-go lexical decision task. The results of this study showed that the P200 waveform is sensitive to the frequency of the first phonological syllable; specifically, pseudo-words with higher phonological first-syllable frequency produced a lower P200 amplitude than those with lower phonological first-syllable frequency. The orthographic syllable frequency did not affect the P200 waveform. The present result implies that there may be different routes by which phonological syllables and orthographic syllables are processed during the early stage of the visual word recognition process.
In studies of bilingual word processing, the primary question has been [corrected] whether various bilingual lexical information is selectively or nonselectively activated. [corrected] Specifically, when a reader processes a [corrected] second language, the lexical properties of the first language can influence the processing of the second language, or vice versa. Phonological priming was significant for both target languages with 50 msec. duration of the priming presentation. [corrected]
Korean writing is a syllabary where spaces occur between phrases rather than between words. This characteristic of Korean allows different types of information in Korean sentences to be dissociated in ways that are not possible in the languages that have been the focus of most psycholinguistic research, thereby providing new opportunities to investigate mechanisms of ambiguity resolution during sentence comprehension. In experiments using eye-tracking and self-paced reading, we examined how readers resolve the Eojoel ambiguity, where the grouping of syllables is ambiguous with respect to whether a phrase-final syllable is a case marker or a part of a word. This Eojoel ambiguity offers an opportunity to test how relative frequency of the lexical entries and complexity of morphological decomposition affect ambiguity resolution. Overall, the results of the experiments presented here showed that readers noticed and processed the Eojoel ambiguity very rapidly using information about the relative frequency of alternative interpretations, while the complexity of the morphological decomposition had little effect. These results are discussed in terms of constraint-based accounts (MacDonald et al. Psychol Rev 101:676-703, 1994) of ambiguity resolution.
The purpose of this study was to examine whether the N400 is affected by the semantic richness of associated neighboring word members or by the density of the orthographic syllable neighborhood. Another purpose of this study was to investigate the source of the different LPC in respect to the semantic richness. To do so, the density of the syllable neighborhood and the size of the morphological family of a word were orthogonally manipulated. ERPs from 24 participants were collected during a go/no-go semantic categorization task. The results showed that the N400 effect was mainly influenced by the density of the syllable neighborhood rather than by the morphological family size. The results also showed that words with a larger morphological family size generate significantly larger LPC than words with a smaller morphological family size. The present study did not support the assumption that the main source of the N400 effect is the semantic richness of the associated neighbors. The present results suggest that the N400 is more sensitive to the density of the syllable neighborhood and LPC is sensitive to the density of the semantic neighborhood reflected by the morphological family size.
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