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ABSTRACT: The brain structure mismatch between western and eastern people may lead to an inappropriate interpretation of neurocognitive studies. To minimize this interracial misinterpretation, we developed the National Taiwan University Chinese Brain Template (NTU-CBT).
102 (M/F = 55/47) healthy Chinese subjects were recruited and received 3T MR brain scans. The template development processes were based on the construction process of Montreal Neurological Institute (MNI) template. Further pilot functional magnetic resonance imaging (fMRI) studies with blocked design visual stimulation and foot tapping task were performed on 3 volunteers and applied to both MNI template and NTU-CBT for analyses.
7 subjects were excluded due to motion artifacts. The average brain size of 95 (M/F = 50/45) subjects was 16.0 cm in length, 13.9 cm in width and 11.3 cm in height, which was 88.9%, 97.9% and 84.3% of the size of MNI template, respectively. Maximum dimensional differences came from the height of superior brain and the length of posterior brain. The average activation voxel volume of the fMRI studies applying to NTU-CBT was 80.7% of that to MNI template in visual stimulation, and 72.8% in foot tapping task. Noticeable mismatches were noted between interpolating original data to NTU-CBT and MNI template.
Morphologic differences between MNI template and NTU-CBT do lead to spatial mismatch in functional studies, especially at cortical regions of superior and posterior brain. With the development of NTU-CBT, we look forward to more accurate interpretation in neurocognitive studies for Chinese subjects.
Conference proceedings: ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference 01/2009; 2009:4779-82.
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ABSTRACT: In order to conduct the longitudinal fMRI study, measuring of the reproducibility of functional imaging is important. Our immediate study, we compared the spatial activation map reproducibility of three fMRI techniques with 8 Hz checkerboard visual stimuli in three experiment sessions. The interval from experiment session one session two is one hour, and the interval form experiment session one to session three is three months. In addition to traditional blood oxygenation level dependent (BOLD) fMRI, CBF and CBV fMRI measured by flow-sensitive alternating inversion recovery (FAIR) and vascular space occupancy (VASO), techniques were also used The latter two developed techniques are more suitable in comparing the longitudinal variation of single subject or among subjects since the quantification capability of CBF and CBV. However, signal change of FAIR and VASO is smaller than BOLD (1/2 and 1/3, respectively) and may reduce the reproducibility of fMRI activation. An equivalent ROI of three techniques was selected in which contained all the activation areas located around primary visual cortex. Percentage of activation overlapping was then calculated from three experiments. The mean overlapping percentage of 7 participants between experiment session one and two was 67.0%, 63.7%, and 65.2%, for BOLD, FAIR, and VASO respectively. There is no significant difference in reproducibility among these techniques. Although FAIR showed slightly better overlapping percentage (61.9%) than the percentage of BOLD and VASO (54.0% and 56.7%) in experiment session one and three, there is still no significant difference between three fMRI techniques. This result indicated that there is no significant difference of reproducibility between three fMRI techniques, although FAIR and VASO show smaller signal change than BOLD.
Noninvasive Functional Source Imaging of the Brain and Heart and the International Conference on Functional Biomedical Imaging, 2007. NFSI-ICFBI 2007. Joint Meeting of the 6th International Symposium on; 11/2007
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ABSTRACT: Twelve patients with idiopathic, congenital, symmetric, moderate-to-severe sensorineural hearing loss participated in this study. Functional magnetic resonance imaging was performed while speech sounds were presented to each patient monaurally. Notable blood oxygenation level-dependent responses were clustered mainly in the superior temporal gyrus and transverse temporal gyrus of both hemispheres during right and left ear stimulation. In addition, the middle temporal gyrus of the right hemisphere was activated during right ear stimulation. The activation pattern was very similar to that of participants with normal hearing. Thus, as long as peripheral acoustic stimulation has not been totally absent from childhood, the classical activation pattern can be elicited in patients with congenital bilateral hearing impairment.
Neuroreport 10/2007; 18(14):1483-6. · 1.66 Impact Factor
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ABSTRACT: The functional significance of age-related pathology of the auditory cortex is not well established. The purpose of this study was to elucidate the activation pattern of the auditory cortex in aged subjects in response to speech signals. Functional magnetic resonance imaging was performed on 12 elderly subjects with normal hearing acuity during selective listening with both ears to speech sounds in quiet and in white noise. Twelve young, normal-hearing subjects served as controls. Our results showed that activation of the auditory cortex during selective listening to speech decreased in elderly subjects compared to young subjects, especially in noise. Reduced activation occurred in the anterior and posterior regions of the bilateral superior temporal gyrus (STG), but mainly in the posterior part of the left STG. In addition, background noise had a greater masking effect on speech perception in the elderly subjects than in the young ones. These findings suggest that early functional changes associated with central presbycusis occur mainly in the posterior part of the left STG.
Audiology and Neurotology 02/2007; 12(5):285-94. · 2.46 Impact Factor
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ABSTRACT: 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.
The purpose of this study was to investigate the changes in the activation pattern of auditory cortex following long-term monoaural amplification.
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.
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.
Acta Oto-Laryngologica 01/2007; 126(12):1275-80. · 1.08 Impact Factor
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ABSTRACT: 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.
Neuroreport 10/2006; 17(13):1397-401. · 1.66 Impact Factor
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ABSTRACT: 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.
The purpose of this study was to investigate the effects of masking on the central auditory system during speech listening in white noise.
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.
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.
Acta Oto-Laryngologica 10/2006; 126(9):916-20. · 1.08 Impact Factor
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ABSTRACT: 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.
ORL 02/2005; 67(4):242-6. · 0.91 Impact Factor
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ABSTRACT: Some people are able to read images or words by using their fingers rather than their eyes. Such capability of finger reading has been studied since 1979. However, the mechanism of the finger-reading phenomenon is still a mystery and remains controversial. To investigate this phenomenon, we provided a preliminary observation of finger reading capability by using functional magnetic resonance imaging (fMRI). In repeated eight experiments, some areas in the brain showed significant activations during finger-reading experiments, especially located in the thalamus, the posterior cingulated and temporal gyrus. These results give some indications to the understanding of the finger-reading phenomenon. Our subject was a 19-year-old, right-handed female student who was gifted with natural finger-reading ability. Hundreds of target samples were prepared by printing numbers or characters on white pieces of paper before experiment. Samples were folded to such a degree that the pattern could not be seen from outside. One of the folded samples was chosen and put into one opaque bag before finger-reading experiment. Her right hand and the opaque bag were tied tightly with cuffs around her forearm. When the experiment began, the subject touched and felt what the characters or numbers are on the folded sample. The subject would "see" one part of the colored characters suddenly, and then disappeared. Each time the process happened, the subject was asked to press the alarm ball to inform us that she had some vision at that time, and we recorded it as the onset time of her physiological paradigm. The process of finger-reading repeated several times until all the characters were exactly recognized. Results of 8 finger-reading experiments and 2 visual stimulation experiments, using 8-Hz checkerboard with three stimulations and four control periods with 20 seconds per period, were collected. Experiments were performed on a Bruker 3T ParaVision system (Bruker, Ettlingen, Germany) with a birdcage head coil. Images were acquired using gradient-echo echo planar image (EPI) with matrix size of 128 × 128, TE of 35 ms, and TR of 2 sec. The first three experiments (a, b, c) had 5 continuous slices with slice thickness of 5 mm, field of view of 40 × 40 cm 2 , and the last five
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ABSTRACT: The neural network associated with idiopathic hyperacusis is still not well known. We studied the brain activation of 3 middle-aged patients with mild to moderate hyperacusis by functional magnetic resonance imaging while they were listening to white noise binaurally. In addition to the temporal lobes, in all patients, sound elicited activation in the frontal lobes (superior, middle, or inferior frontal gyri) and occipital lobes (precuneus, cuneus, superior occipital gyrus, lingual gyrus, or fusiform gyrus). The parahippocampus was activated in 2 of 3 patients. Furthermore, the precentral and postcentral gyri, superior and inferior parietal lobules, thalamus, midbrain, claustrum, insula, posterior cingulated gyrus, and orbital and rectal gyrus were also activated in one patient. The neural network associated with idiopathic hyperacusis might be associated with the frontal lobes and parahippocampus.
American journal of otolaryngology 30(6):432-4. · 0.77 Impact Factor
