Biomedical subjects

Chang-Wei Wu

Publications and source records attributed to Chang-Wei Wu.

4 recordsLinked to original sources

PubMed2006

Dissociated roles of the middle frontal gyri in the processing of Chinese characters.

The present study examined a hypothesis that the right middle frontal gyrus participates in processing orthography of Chinese characters, while the left middle frontal gyrus mediates access to phonology and semantics. Brain activation during three character tasks, which required processing orthography, phonology, or semantics of Chinese characters, respectively, was measured by functional magnetic resonance imaging. Comparable neural activity in the right middle frontal gyrus was observed in all three character tasks that always demand orthographical processing. In contrast, the left middle frontal gyrus showed greater activation in the phonological and semantic tasks than in the orthographic task. These results suggest that the right and left middle frontal gyrus have dissociable functions in achieving Chinese character recognition.

Adult↗

PubMed2006

The effects of masking on the activation of auditory-associated cortex during speech listening in white noise.

CONCLUSIONS: Noise-induced masking has different effects on the two hemispheres during speech listening. Auditory-associated cortices in the left hemisphere were more affected by masking than the right side. However, activation of primary and secondary auditory cortices was not affected in both sides under the masking with high signal to noise ratio. OBJECTIVES: The purpose of this study was to investigate the effects of masking on the central auditory system during speech listening in white noise. MATERIALS AND METHODS: Twelve healthy young subjects with normal hearing participated in this study. Functional magnetic resonance imaging (fMRI) was performed while subjects were listening to speech sounds alone and speech plus white noise binaurally. RESULTS: In humans, the activation of several regions including the middle parts of the superior and middle temporal gyri, parahippocampal gyrus, cuneus and thalamus of the left hemisphere was significantly reduced under the masking paradigm with +5 dB signal to noise ratio. In addition, reduced activation was also found at the lingual gyrus, anterior and middle parts of the superior temporal gyrus (STG), uncus, fusiform gyrus, and inferior frontal gyrus of the right hemisphere during masking.

Acoustic Stimulation↗

PubMed2006

Changes in activation of the auditory cortex following long-term amplification: an fMRI study.

CONCLUSION: Speech-elicited activation decreased after monaural amplification bilaterally during unaided or aided ear stimulation, but tended to recover later at the contralateral hemisphere during aided ear stimulation. OBJECTIVES: The purpose of this study was to investigate the changes in the activation pattern of auditory cortex following long-term monoaural amplification. PATIENTS AND METHODS: Serial functional magnetic resonance images were obtained while speech sounds were presented to the aided (right) and unaided (left) ears of eight hearing-impaired subjects before, 3 months, and 9 months after beginning the use of a single hearing aid. The results were analyzed by group analysis. RESULTS: Before hearing aid fitting, we found that activation patterns of the auditory cortex were somewhat segmented in the left hemisphere, regardless of whether the speech sounds were delivered to right or left ear. Cross projection was lost in response to right ear stimulation. After hearing aid fitting, on the unaided side stimulation, the activation tended to decrease progressively on both sides 3 months and 9 months after beginning monoaural amplification. On the aided side stimulation, activation also decreased 3 months after amplification bilaterally, but tended to recover at the contralateral hemisphere after 9 months of amplification. Cross projection was restored in response to right ear stimulation.

Acoustic Stimulation↗

PubMed2005

Hemispheric difference in activation patterns of human auditory-associated cortex: an FMRI study.

The purpose of this study was to demonstrate interhemispheric differences in activation patterns of the auditory-associated cortex elicited by a series of sounds. Functional magnetic resonance imaging was performed while different sounds were presented binaurally to 10 healthy subjects with normal hearing. Characteristic activation patterns were elicited although variability was shown between subjects. The activation number was significantly higher on the right than on the left side for non-speech (but not for speech) stimulations. As stimulation increased in complexity (from a pure tone to white noise to ocean wave sounds to classical music), the activation pattern of the superior temporal lobe became more pronounced in both hemispheres while that of the auditory cortex tended to become more sustained and concentrated on the right rather than on the left side. No hemispheric differences in activation pattern were seen in response to speech.

Acoustic Stimulation↗