Browsing by Author "Shih, Yen-Yu"

Now showing 1 - 3 of 3

DYNAMIC MAPPING OF AMPHETAMINE RESPONSE IN THE RAT BRAIN USING BOLD AND IRON TECHNIQUES
(2007-06-01)
Shih, Yen-Yu
;
Chen, You-Yin
;
Hsieh, Wen-Yuan
;
Huang, Ying-Yuan
;
Chang, Chen
Conventional blood oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI) has been wildly used in neuroscience studies. Even though the BOLD method offers the functional information, the low signal-to-noise ratio could not provide an activated brain area accurately and the signal could not be easily inspected from the complicated neuronal interactions. In this regard, the present study aims to use an ultra-small super-paramagnetic iron oxide (USPIO) nanoparticle coated with covalently bound bifunctional poly(ethylene glycol) polymers to enhance the brain functional responses by the IRON (increased relaxation with iron oxide nanoparticles) technique. The R1 and R2 of this USPIO were 53.6 mMsec-1 and 359.8mMsec-1, respectively, and both were higher than most of the commercial products under 0.47 T nuclear magnetic resonance measurement. In this study, the time activity curves in responsive brain areas were evaluated following USPIO injection (3 mg of Fe/kg). The amphetamine (2 mg/kg) was used as a functional stimulator to reveal the changes of relative cerebral blood volume in different brain areas. All imaging experiments were performed by Bruker Biospec BMT 47/40 4.7 T MRI system. The results show that, compared to the BOLD signals; significant event related responses were observed in striatum, insular cortex, nucleus accumbens, somatosensory cortices, and lateral thalamus using the IRON technique. Furthermore, the usability of this USPIO in detecting rCBV responses was confirmed by comparing with previous researches.
Exploring nociceptive response by BOLD MRI in alpha-chloraRose anesthetized rats
(2006-01-01)
Shih, Yen-Yu
;
Chen, You-Yin
;
Chen, Jin-May
;
Lung, Yun
;
Chen, Jun-Ying
The technique of blood oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI) was used to provide a spatial-temporal mapping of nociceptive activation in brain. We contrived to obtain an illustration of the pain related regions by injecting formalin at the hindpaw using a 4.7 T MR system in a-chloralose anesthetized rats. In order to obtain the pain response, we avoided any invasive surgery on animals to purify the signal of nociception. The dynamic data were analyzed by mapping correlation coefficient and the time activity curves were calculated by atlas-based region of interest selection. The BOLD signals showed obvious difference in anterior cingulated cortex, somatosensory cortex, medial thalamus, and striatum after stimulation. The results not only show the global somatotopic organization of noxious stimulation on hindpaw in rats, but also provided invaluable information for neuroscience research.
ISPMER: Integrated system for combined PET, MRI, and electrophysiological recording in somatosensory studies in rats
(2007-10-01)
Shih, Yen-Yu
;
Chen, You-Yin
;
Chen, Jyh-Cheng
;
Chang, Chen
;
Jaw, Fu-Shan
The present study developed an integrated system for use in combined PET, MRI, and electrophysiological recording in somatosensory studies in rats, called ISPMER. A stereotaxic frame was designed for animal positioning that could be used in all three measurement modalities, and its dimensions complied with the gold standard of the Paxinos and Watson rat brain atlas. A graphical user interface was developed for analyzing the data using several signal processing algorithms. This integrated system provides a novel interface for the recording and processing of three-dimensional neuronal signals in three modalities. (c) 2007 Elsevier B.V. All rights reserved.