An fMRI study of grammatical morpheme processing associated with nouns and verbs in Chinese

This study examined whether the degree of complexity of a grammatical component in a language would impact on its representation in the brain through identifying the neural correlates of grammatical morpheme processing associated with nouns and verbs in Chinese. In particular, the processing of Chinese nominal classifiers and verbal aspect markers were investigated in a sentence completion task and a grammaticality judgment task to look for converging evidence. The Chinese language constitutes a special case because it has no inflectional morphology per se and a larger classifier than aspect marker inventory, contrary to the pattern of greater verbal than nominal paradigmatic complexity in most European languages. The functional imaging results showed BA47 and left supplementary motor area and superior medial frontal gyrus more strongly activated for classifier processing, and the left posterior middle temporal gyrus more responsive to aspect marker processing. We attributed the activation in the left prefrontal cortex to greater processing complexity during classifier selection, analogous to the accounts put forth for European languages, and the left posterior middle temporal gyrus to more demanding verb semantic processing. The overall findings significantly contribute to cross-linguistic observations of neural substrates underlying processing of grammatical morphemes from an analytic and a classifier language, and thereby deepen our understanding of neurobiology of human language.published_or_final_versio

The relationship between affective word ratings and lexico-semantic properties in Cantonese actions and objects

The aim of the present study was to develop a set of Cantonese nouns and verbs with ratings for various affective and lexico-semantic features identified in previous studies in English and other languages. The majority of stimuli were found to be neutral in rated valence and low in arousal. Significant correlations were found among affective features, among lexico-semantic features and between each of the two feature types. This pattern of correlations differs from a prior study using adjectives as stimuli. Moreover, arousal was minimal in neutral words, but was higher in negative and positive words. Multiple regression analyses identified different predictors for the affective features when ratings from all participants were analyzed together, and when noun and verb ratings from the young and old participants were analyzed separately. The results show that although monosyllabic object and action terms in Cantonese are not likely to be confounded with emotional characteristics in research studies, multicollinearity between lexical-semantic variables demands careful control over correlated factors when selecting stimuli for research into category specific effects in aphasia with Cantonese speakers.published_or_final_versionSpeech and Hearing SciencesBachelorBachelor of Science in Speech and Hearing Science

Cognitive control and language network connectivity associated with language production in aphasia

Aphasia is the breakdown of language comprehension and production due to an acquired brain injury of the left hemisphere. Investigation of the neurological underpinnings of aphasia have advanced from post-mortem investigation of specific regions in the 1800s to the utilization of brain imaging technology to understand brain networks. These approaches have helped us to appreciate the reorganization of the brain and its networks post stroke, particularly as it relates or is modified for adequate versus impaired performance. Research into neuroplastic changes can elucidate differences between healthy and lesioned brains. Furthermore, identification of adaptive (or maladaptive) neuroplastic changes can also inform diagnostics or aid in monitoring the neuroplastic effects of evidence-based treatment. This study utilized resting state functional MRI to characterize graph theory metrics of language (LN) and cognitive control networks (frontoparietal, FPN) in 21 persons with aphasia (PWA) and 18 healthy controls (HC). This study further investigated the relationship between strength of connectivity and semantic access and errors in PWA during a picture description task. When comparing resting state network connectivity of the LN in PWA vs. HC, many edges (10/14) and node degree hubs (3/3) were common to both groups for the LN, suggesting that an inherent network that remains relatively intact even post-stroke. Analyses yielded similar results for resting state FPN network connectivity with common edges and node degree hubs. When investigating correlations between network edges and language measures, correlations between FPN edges and CIU’s and retracing suggested the importance of right hemisphere and ‘healthy’ edge integrity

Dissociative neural correlates of semantic processing of nouns and verbs in Chinese - A language with minimal inflectional morphology

Numerous studies using various techniques and methodologies have demonstrated distinctive responses to nouns and verbs both at the behavioral and neurological levels. However, since the great majority of these studies involved tasks employing pictorial stimuli and languages with rich inflectional morphology, it is not clear whether word class effects resulted from semantic differences between objects and actions or different inflectional operations associated with the two word classes. Such shortcomings were addressed in this study by using a language with impoverished inflectional morphology - Chinese. Both concrete and abstract words were included, while controlling for nuisance variables between the two word classes, including imageability, word frequency, age-of-acquisition, and number of stroke. Participants were asked to judge the semantic relatedness of noun or verb pairs by pressing different buttons. The results revealed specific neural correlates for verb class in left lateral temporal and inferior frontal regions. Furthermore, the patterns of neural distribution of nouns and verbs were consistent with observations from Indo-European languages. Plausible accounts for neural separation of word classes were considered. © 2011 Elsevier Inc.link_to_subscribed_fulltex