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Biomedical subjects

Zhen Jin

Publications and source records attributed to Zhen Jin.

At least 19 recordsLinked to original sources

Sex determines the neurofunctional predictors of visual word learning.

This study used functional MRI and an artificial language training paradigm to explore sex differences in the processing of a new writing system and how sex determines the optimal neural resource recruitment for visual word learning. Results indicated that males and females achieved equal learning outcome, and their learning curve followed a similar power function. They also showed similar overall activation in the fusiform cortex, a region that has been associated with visual word processing. Despite the absence of sex differences in averaged behavioral performance and neural activation, males and females were found to have different neural predictors of visual word learning. As predicted, left-lateralized fusiform activation predicted visual word learning for males, but not for females, whereas bilateral fusiform activation predicted visual word learning for females, but not males. These results suggest that male and female brains operate differently to achieve the best performance in visual word learning. The individual-differences approach adopted in the present study provides a new and useful perspective to sex differences.

Adult↗

Spatial organization and evolution period of the epidemic model using cellular automata.

We investigate epidemic models with spatial structure based on the cellular automata method. The construction of the cellular automata is from the study by Weimar and Boon about the reaction-diffusion equations [Phys. Rev. E 49, 1749 (1994)]. Our results show that the spatial epidemic models exhibit the spontaneous formation of irregular spiral waves at large scales within the domain of chaos. Moreover, the irregular spiral waves grow stably. The system also shows a spatial period-2 structure at one dimension outside the domain of chaos. It is interesting that the spatial period-2 structure will break and transform into a spatial synchronous configuration in the domain of chaos. Our results confirm that populations embed and disperse more stably in space than they do in nonspatial counterparts.

Journal Article↗

Neural substrates for forward and backward recitation of numbers and the alphabet: a close examination of the role of intraparietal sulcus and perisylvian areas.

Despite numerous studies on the neural basis of numerical processing, few studies have examined the neural substrates of one of the most basic numerical processing-number sequence recitation. The present study used fMRI to investigate neural substrates of number sequence recitation, focusing on the intraparietal sulcus (IPS) and perisylvian areas. This study used a 2 (number versus alphabet) x 2 (forward versus backward recitation) design. 12 Chinese undergraduates were asked to recite overtly but gently numerical and alphabetical sequences forward and backward. Results showed that, for both numerical and alphabetic sequences, the left IPS was activated when performing backward recitation, but not when performing forward recitation. In terms of perisylvian areas, all four tasks elicited activation in bilateral superior temporal gyrus and inferior frontal gyrus, but forward recitation elicited greater activation in the left posterior superior temporal gyrus than did backward recitation, whereas backward recitation elicited greater activation in the left inferior frontal gyrus than did forward recitation. These results suggest that forward recitation of numbers and the alphabet is typically based on verbal processing of numbers implemented in the perisylvian area, whereas backward recitation would likely require additional neural resources in the IPS.

Adolescent↗

Language experience shapes fusiform activation when processing a logographic artificial language: an fMRI training study.

The significant role of the left midfusiform cortex in reading found in recent neuroimaging studies has led to the visual word form area (VWFA) hypothesis. This hypothesis suggests that years of experience reading native language change the visual expertise of this region to be especially sensitive to the visual form of native language. The present study aimed at testing this hypothesis by exploring the role of language experience in shaping the fusiform activation. We designed a logographic artificial language (LAL) using the visual form and pronunciation of Korean Hangul characters (but their correspondence was shuffled) and assigning arbitrary meanings to these characters. Twelve native Chinese Mandarin speakers (6 male and 6 female, 18 to 21 years old) with no prior knowledge of Korean language were trained in the visual form of these characters for 2 weeks, followed by 2 weeks each of phonological and semantic training. Behavioral data indicated that training was effective in increasing the efficiency of visual form processing and establishing the connections among visual form, sounds, and meanings. Imaging data indicated that at the pre-training stage, subjects showed stronger activation in the fusiform regions for LAL than for Chinese across both one-back visual matching task and the passive viewing task. Visual form training significantly decreased the activation of bilateral fusiform cortex and the left inferior occipital cortex, whereas phonological training increased activation in these regions, and the right fusiform remained more active after semantic training. Increased activations after phonological and semantic training were also evident in other regions involved in language processing. These findings thus do not seem to be consistent with the visual-expertise-induced-sensitivity hypothesis about fusiform regions. Instead, our results suggest that visual familiarity, phonological processing, and semantic processing all make significant but different contributions to shaping the fusiform activation.

Adolescent↗

Specialization of phonological and semantic processing in Chinese word reading.

The purpose of this study was to examine the neurocognitive network for processing visual word forms in native Chinese speakers using functional magnetic resonance imaging (fMRI). In order to compare the processing of phonological and semantic representations, we developed parallel rhyming and meaning association judgment tasks that required explicit access and manipulation of these representations. Subjects showed activation in left inferior/middle frontal gyri, bilateral medial frontal gyri, bilateral middle occipital/fusiform gyri, and bilateral cerebella for both the rhyming and meaning tasks. A direct comparison of the tasks revealed that the rhyming task showed more activation in the posterior dorsal region of the inferior/middle frontal gyrus (BA 9/44) and in the inferior parietal lobule (BA 40). The meaning task showed more activation in the anterior ventral region of the inferior/middle frontal gyrus (BA 47) and in the superior/middle temporal gyrus (BA 22,21). These findings are consistent with previous studies in English that suggest specialization of inferior frontal regions for the access and manipulation of phonological vs. semantic representations, but also suggest that this specialization extends to the middle frontal gyrus for Chinese. These findings are also consistent with the suggestion that the left middle temporal gyrus is involved in representing semantic information and the left inferior parietal lobule is involved in mapping between orthographic and phonological representations.

Acoustic Stimulation↗

Cerebral asymmetry in the fusiform areas predicted the efficiency of learning a new writing system.

There are great individual differences in learning abilities, but their neural bases, especially among normal populations, are not well understood. Using functional magnetic resonance imaging and a training paradigm, the present study investigated individual differences in cerebral asymmetry in fusiform regions when processing a new writing system and their correlation to subsequent visual character learning. Twelve Chinese adults underwent a 2-week training to learn 120 Korean characters and they were scanned before and after the training. Results showed that left-hemispheric dominance during the pretraining task was predictive of better posttraining performance. These results have significant implications for our understanding of the neural basis of language learning, especially in terms of individual differences.

Adolescent↗

[Brain activities during maximum voluntary clenching with and without soft splint in patients with hemimasticatory spasms by functional magnetic resonance imaging].

OBJECTIVE: Functional magnetic resonance imaging (fMRI) was used to detect the cerebral cortical somatotopy during maximum voluntary clenching with and without soft splint in patients with hemimasticatory spasms (HMS) and the central mechanisms of HMS and the rule of the splint therapy. METHODS: Four HMS patients were selected and the spasms sides were right in two cases and left in the other two cases. FMRI images were obtained on Elscint/GE 2.0 Tesla MR system. Block design was used and the movement pattern was the onset of spasms after maximum voluntary clenching with and without soft splint. The fMRI data were analyzed by SPM99 software. RESULTS: With the onset of spasms after maximum voluntary clenching, the activation of motor cortex in 3 HMS patients was found lateral dominance on the left side, and the other one showed bilateral activation. All the 4 patients were found activation in cingulate area. With the onset of spasms after maximum clenching wearing soft splints, the activation of motor cortex showed no lateral dominance on the left side, and 3 patients were not found activation in cingulate area. CONCLUSIONS: The changes of the activation in motor cortex and cingulate area during the onset of spasms after clenching with and without soft splint might be the central mechanisms of the rule of splint therapy, through which the soft splint might function in alleviating muscle pain.

Brain↗

[Functional activity mapping during anticipation of dental pain].

OBJECTIVE: To reveal functional activity mapping during anticipation of dental pain with non-invasive fMRI technique, and to offer therapeutic possibilities for treating chronic oral facial pain psychologically. METHODS: 8 right handed patients with dentinalgia of the right maxillary bicuspid were included in this study. Block design was adopted, BOLD level during anticipation epoch (on) was contrasted with that of rest (off). Functional MRI scan covering the whole brain was carried out. The fMRI data were analyzed by SPM2 software with t-test to generate the activation map. RESULTS: Increased BOLD signals during dental pain anticipation were found dominantly on the left side in inferior, middle frontal gyrus/BA10,46, postcentral gyrus/BA2,3, middle frontal gyrus/BA8, precentral gyrus/BA44 and cerebellum. CONCLUSION: Anticipation of dental pain by itself can activate brain regions, especially prefrontal areas, SI, SMA and cerebellum. The results of pain anticipation are consisted with previous studies except that there is no activation in insula and cingulate cortex. Sensory, motor, cognitive and emotional activation in dental pain anticipation may indicate that brain nociceptive network can be affected by hint.

Adult↗

[Multiresidue determination of organophosphorus pesticide residues in vegetables and fruit by gas chromatography-negative ion chemical ionization-mass spectrometry].

An analytical method of gas chromatography coupled with negative ion chemical ionization-mass spectrometry for simultaneous determination of nine organophosphorus pesticide residues in vegetables and fruit has been developed, and the negative ions structure and partition mechanism of the nine organophosphorus pesticides were interpreted. Meanwhile, the matrix effect for sample analysis was discussed, and matrix-matched calibration for quantification was introduced to reduce the matrix effect in this method. Pesticides were extracted from sample with ethyl acetate in an ultrasonic bath, then determined by gas chromatography-mass spectrometry operated in negative chemical ionization mode and quantified in selective ion monitoring mode, and ethion was used as an internal standard. The detection limits of the method were 0.12-1.0 microg/kg for the nine organophosphorus pesticides, and the relative coefficients were higher than 0.9993. A blank sample (tomato) was spiked at 100, 400, 800 microg/kg for each pesticide, and the recoveries were determined to be from 78% to 126% with relative standard deviations from 0.58% to 14.7% for the pesticides.

Agriculture↗

[Determination of multiple pesticide residues in honey using gas chromatography-mass spectrometry].

An analytical method was developed for the simultaneous determination of 23 pesticide residues in various commercial honeys. Meanwhile, the characteristic ions and fragmentation mechanism of three pesticides in the process of electron ionization mass spectrometry (EI/MS) were evaluated. After the optimization of different parameters such as the extraction solvent, pesticides were extracted from honey with ethyl acetate in an ultrasonic bath, cleaned up on a Florisil column by an elution of mixture of hexane and ethyl acetate (7:3, v/v), and analyzed by gas chromatography-electron ionization mass spectrometry (GC-EI/MS) in the selected ion monitoring mode (SIM) with PCB103 as internal standard. Recovery studies were performed at 50, 100 and 200 microg/kg fortification levels for each pesticide, and the recoveries ranged from 82% to 120% with relative st0ndard deviations between 1.8% and 11.0% for different pesticides. The limit of detection was less than 10.0 microg/kg for all the pesticides. The developed method was linear in the range of 10-500 microg/kg, with correlation coefficients larger than 0.995. Finally, the developed analytical method has been successfully applied to the determination of pesticide residues in several honey samples.

Gas Chromatography-Mass Spectrometry↗

Size-dependent orientation growth of large-area ordered Ni nanowire arrays.

Large-area ordered Ni nanowire arrays with different diameters have been fabricated by the direct current electrodeposition into the holes of porous anodic alumina membrane. The crystal structure and micrograph of nanowire arrays are characterized by X-ray diffraction, field-emission scanning electron microscopy and high-resolution transmission electron microscopy. The results indicate that the growth orientation of Ni nanowires turns from [110] to [111] direction with increasing diameters of nanowires. The mechanism of the growth was discussed in terms of interface energy minimum principle. The size-dependent orientation of Ni nanowire arrays has the important significance for the design and control of nanostructures.

Aluminum Oxide↗

Dissociation in the neural basis underlying Chinese tone and vowel production.

Neuropsychologists have debated over whether the processing of segmental and suprasegmental units involves different neural mechanisms. Focusing on the production of Chinese lexical tones (suprasegmental units) and vowels (segmental units), this study used the adaptation paradigm to investigate a possible neural dissociation for tone and vowel production. Ten native Chinese speakers were asked to name Chinese characters and pinyin (Romanized phonetic system for Chinese language) that varied in terms of tones and vowels. fMRI results showed significant differences in the right inferior frontal gyrus between tone and vowel production (more activation for tones than for vowels). Brain asymmetry analysis further showed that tone production was less left-lateralized than vowel production, although both showed left-hemisphere dominance.

Adult↗

Cerebral asymmetry in children when reading Chinese characters.

This study examined cerebral asymmetry, especially in the hierarchical visual system, when reading Chinese characters. Twelve right-handed Chinese children (mean age = 11.6 years) were scanned while performing semantic and phonological tasks. Strong leftward asymmetry was found in the left inferior frontal cortex (BA44/45/47), the parietal lobule (BA40), and the cingulate cortex (BA24/32). In the visual system, we found significant left-hemispheric dominance in the fusiform cortex (BA19/37), but no asymmetry was found in the primary visual cortex (BA17/18). The differential results for the primary visual cortex versus high-order visual cortex (i.e., the fusiform cortex) are discussed in terms of the contribution of the logographic nature of Chinese characters to the asymmetry pattern in the hierarchical visual system.

Brain Mapping↗

Differences between attention-deficit disorder with and without hyperactivity: a 1H-magnetic resonance spectroscopy study.

Using proton magnetic resonance spectroscopy ((1)H-MRS) to investigate possible neurometabolic differences between the predominantly inattentive subtype (ADHD-I), the combined subtype (ADHD-C) and normal controls. Proton spectra were acquired bilaterally on the lenticular nucleus in 20 schoolboys having ADHD and 10 matched controls. The boys with ADHD were divided into ADHD-C subtype (n=10) and ADHD-I subtype (n=10) according to DSM-IV criteria. The peaks of N-acetylaspartate (NAA), Choline moieties (Cho), myo-inositol (mI), creatine (Cr) and alpha-Glx were measured and their ratios to Cr were calculated. One-way ANOVA and post-hoc Bonferroni tests were used to detect the difference of the peak-area ratios of NAA, Cho, mI, and alpha-Glx to Cr among the three groups. There was a significant overall group difference in the NAA/Cr ratio both in the right and left lenticular nucleus (right: P=0.002; left: P=0.003). Only the ADHD-C subtype group showed a significant difference with controls (right: P=0.001; left: P=0.003) the right lenticular nucleus, the NAA/Cr ratio in the ADHD-C group was significantly lower than that in the ADHD-I group (P=0.012). In the left lenticular nucleus, the NAA/Cr ratio in the ADHD-C group showed a significant trend compared to the ADHD-I group (P=0.06). This study demonstrated the existence of measurable difference between children with ADHD-C and ADHD-I using (1)H-MRS.

Adolescent↗

Functional MRI in attention-deficit hyperactivity disorder: evidence for hypofrontality.

Using event-related functional magnetic resonance imaging to study the Stroop effect on both behavioral and brain activation of ADHD children off or on methylphenidate (MPH). Nine ADHD boys (aged 9.8-14.5 years) and 9 age-matched normal controls were included. A Stroop-like paradigm was used. AFNI (Analysis of Functional NeuroImaging) and its Deconvolution Analysis were used in a descriptive comparison between ADHD and control groups. (1) Both behavioral reaction time and brain activation showed Stroop effect in controls but neither was found in ADHD children off MPH. When MPH was administered, the Stroop effect tended to appear. (2) The activation volume (AV) of prefrontal cortex (PFC) in both the neutral (NC) and interference conditions (IC) in ADHD children off MPH was smaller than in controls. AV of anterior cingulate cortex in the IC in ADHD children off MPH was smaller than that in controls, but was similar in the NC to that in controls. AV of the basal ganglia, insula and cerebellum was also smaller in the IC, but was larger in the NC for ADHD children off MPH compared with controls. These findings are consistent with prior findings of hypofrontality in ADHD children and implicate a compensatory network including basal ganglia, insula and cerebellum for relative lower cognitive load tasks.

Adolescent↗

[Brain activities during maximum voluntary clenching with soft occlusal pad in healthy adults by functional magnetic resonance imaging].

OBJECTIVE: Using functional magnetic resonance imaging (fMRI) to detect the cerebral cortical somatotopy during maximum voluntary clenching with soft occlusal pad in healthy adults. By comparing with the cerebral cortical activation during clenching with and without soft occlusal pad we try to detect the central mechanism of the rule of the occlusal pad. METHODS: Ten healthy subjects were selected and scanned by Elscint/GE 2.0 Tesla MR system. Block design was used and the movement pattern was maximum voluntary clenching with soft occlusal pad. The fMRI data were analyzed by SPM99 software and group map analysis was done. RESULTS: The activation areas were found in bilateral or unilateral motor cortex, somatosensory cortex, prefrontal cortex, temporal cortex, premotor cortex, insula, frontal operculum, basal ganglia (putamen), parietal cortex and cingulate. Group map analysis showed activation in bilateral motor cortex, right somatosensory cortex, bilateral basal ganglia, and bilateral insula. The activation of left motor cortex was significantly higher than right side. Compared with cortical activation without occlusal pad, the motor and somatosensory cortex changed a lot. CONCLUSION: The changes of the activation of motor and somatosensory cortex during clenching after wearing the soft occlusal pad might be the central mechanism of the rule of the occlusal pad.

Adult↗

[Changes of matrix metalloproteinase-9 and effect of diazepam on its expression in uterine lower segment during delivery].

OBJECTIVE: To investigate the role of matrix metalloproteinases (MMPs) in onset of labor, and the mechanism of diazepam in promoting cervical ripening. METHODS: Concentrations of MMP-9 in lower segment of uterus from the group of cesarean section with (56 cases) and without (16 cases) uterine contraction were measured by enzyme linked immunosorbent assay (ELISA) method. Human cervical mechanocytes were cultured respectively with different concentrations of diazepam (0, 0.1, 10, 100 micromol/L). Semi-quantitative RT-PCR was used to study the expression of MMP-9 mRNA, and MMP-9 contents in culture supernatant were measured by ELISA methods. RESULTS: The concentration of MMP-9 in uterine lower segment tissue in the group of cesarean section with uterine contraction, (3.1 +/- 2.6) ng/mg, was significantly higher than that in the group of cesarean section without uterine contraction, (0.8 +/- 0.4) ng/mg (P < 0.05). In the 1st-stage-labour group from the 44 cases of cesarean section with uterine contraction, MMP-9, (2.2 +/- 2.0) ng/mg, tended to increase with the dilatation of cervix. MMP-9 in the 12 cases of 2nd-stage-labour group was (6.1 +/- 2.5) ng/mg, which was significantly higher than that in the 1st-stage-labour group (P < 0.05). The relative expressions of MMP-9 mRNA in the cells of the blank control group and those with diazepam at final concentrations of 0.1, 10 micromol/L were all time dependent, in another word, the expressions gradually increased over time. There was a remarkable difference between the two groups and blank control group (P < 0.05). In the blank control group and group with diazepam at final concentration of 0.1 micromol/L, the MMP-9 contents in supernatant showed a time dependent increase, with a significant difference between the two groups (P < 0.05). CONCLUSIONS: MMPs are key mediator in the onset of labor, maturation and dilatation of uterine cervix. Our studies suggest that human cervical mechanocytes play a role in synthesizing and secreting MMP-9 naturally; and diazepam might promote those activities of mechanocytes, thus in part accelerating the degradation of collagen fibers and cervical ripening.

Adjuvants, Anesthesia↗

[Clinical characteristics and diagnosis of neuronal migration disorders].

OBJECTIVE: Neuronal migration disorders (NMD) are a group of malformations of the brain which ultimately disrupt migrating neuroblasts from the germinal plate to the cerebral cortex, it consists of agyria-pachygyria, polymicrogyria, schizencephaly, hemimegalencephaly and heterotopia. This study aimed to investigate the clinical characteristics and diagnostic methods of NMD. METHODS: The clinical data, cranial imaging and experimental examinations of 37 patients with NMD were analyzed. The patients consisted of 21 males and 16 females whose age of first hospital visit ranged from 2 months to 14 years and 6 months. Among the 37 cases, 18 were followed up. RESULTS: Of the 37 patients, 21 were agyria-pachygyria, the main clinical manifestations were mental retardation (20 cases), epilepsy (14 cases), hemiparesis (6 cases), and 17 patients had microcephaly which was an important physical sign. Eight patients had agyria-pachygyria with other malformations, they presented mental retardation (6 cases), epilepsy (4 cases), and hemiparesis (2 cases). Of the 5 patients with heterotopia, 4 manifested epilepsy. 3 patients had schizencephaly and 2 presented with hemiparesis. EEG was performed in 16 cases. Generalized irregular sharp and slow wave complexes were present in 10 cases, focal spike and slow complex in one case, hypsarrhythmia in one case, and the normal EEG in 4 cases. Eighteen cases were followed-up from seven months to eight years and three months, 14 patients had epilepsy, and still had epileptic attacks with the treatment with anticonvulsives, motor development was improved but speech development delayed in 4 cases. CONCLUSION: The results of this study suggest that NMD is characterized by mental retardation, epilepsy and hemiparesis. Cranial MRI is the best diagnostic method.

Adolescent↗