Ambient modulation of neuronal excitability / 生理学报

Although the modulation of synaptic activity plays an important role in the modulation of neuronal excitability, the significance of the ambient modulation (AM) of neuronal excitability should be emphasized. The AM refers to the alterations of membrane potential of neuron resulted from distinct neural activities, such as the tonic inhibition and excitation through activation of extra-synaptic receptors, the paracrine actions of nearby neural and non-neural cells, endocrinal actions of blood borne hormones and other active chemical substances. The AM of neuronal excitability may have important bearings on distinct brain functions, such as the regulation and switching of cortical states, the appearance of chaotic and vague feelings, which are usually the characteristic features in many mental and neural disorders.

Sixty years after Hsiang-Tung Chang's presentation on dendrite at the Cold Spring Harbor Symposium / 生理学报

Sixty years elapsed since Chang (Hsiang-Tung Chang, Xiang-Tong Zhang) presented his seminal report "Cortical neurons with particular reference to the apical dendrite" at the Cold Spring Harbor Symposium. Thanks to the development of elaborated techniques through the 6 decades, our understanding of the dendrite has been pushed forward greatly: the backward and forward conductions during excitation, sodium and calcium conductances, chemical excitation by uncaging glutamate at a dimension of micrometer, and the quantitative study of chemical organization of postsynaptic density (PSD), etc. Though the progression is great, there are still tough problems in dendritic research, especially the integration through dendritic spine.

Study of paroxysmal kinesigenic dyskinesia with fMRI / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To detect the differences in subcortical structures between patients with paroxysmal kinesigenic dyskinesia (PKD) and normal subjects during movement preparation and execution.</p><p><b>METHODS</b>The PKD patients performed a movement task, in which a CUE signal (preparation) indicated the movement sequence prior to the appearance of an imperative GO signal (execution). Event-related functional magnetic resonance imaging (fMRI) and 3dDeconvolve program of AFNI were used to estimate the hemodynamic response function and to generate activation maps.</p><p><b>RESULT</b>During movement preparation, the activated brain areas in PKD patients were less than those of normal subject, and there was no activation in basal ganglia in PKD patients. During execution, the activation was also less in PKD patients except in bilateral M1.</p><p><b>CONCLUSION</b>During intermission, abnormalities of the brain still exist in PKD patients when during preparing or performing movement. The movement circuit in the brain displays an unusual state. The attack may be caused by reducing of inhibition in brain areas.</p>

Functional MRI of human brain in musicians and non-musicians / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To explore the differences in brain activation between musicians and non-musicians by use of functional MRI.</p><p><b>METHODS</b>Twelve right-handed musicians and twelve right-handed non-musicians were recruited in the study. During a listening task, they were scanned on the Sigma 1.5T scanner (GE) while they were passively listening to several segments of music of "the Butterfly Love" and the white noise with same physical energy.</p><p><b>RESULT</b>Both musicians and non-musicians demonstrated bilateral transverse gyrus weak activated while listening to the white noise. But when listening to music, they showed bilateral temporal areas strongly activated including superior temporal gyrus, transverse gyrus and some middle temporal areas. Moreover, musicians showed relative left dominance (10/12), whereas non-musicians demonstrated right dominance(11/12). Furthermore,besides bilateral temporal areas, more and stronger activated areas were found in musicians such as cuneus, precuneus,medial frontal and left middle occipital gyrus.</p><p><b>CONCLUSION</b>There are different neuro-patterns between musicians and non-musicians.</p>

Lateralized distribution of motor areas involved in voluntary movement / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the brain functional laterality in motor areas during motor execution systematically.</p><p><b>METHODS</b>Functional magnetic resonance imaging (fMRI) was employed combined with right hand sequential finger movement task to investigate brain activation pattern and laterality in 8 right-handed subjects. 3dDeconvolve program of AFNI was used to estimate the hemodynamic response function and to generate activation maps. Then the laterality index (LI) was calculated and tested statistically.</p><p><b>RESULT</b>All motor areas including the areas which were previously considered to be engage in movement preparation only were activated in movement execution. In the activation map, it appeared left lateralization in cerebra and right lateralization in cerebella. After further statistical test, it was found that in primary motor area (M1), supplementary motor area (SMA) and posterior parietal cortex (PPC), there were left lateralization. While in premotor cortex (PMC), cingulate gyrus and basal ganglia (BG), the lateralization tendency was not obvious. The activation in cerebella is characterized with right lateralization.</p><p><b>CONCLUSION</b>Though there are tiny differences among subjects, most of the motor areas appear lateralized activation. Past studies only observed laterality in several motor areas. It may be due to the difficulty of the task or the experimental design.</p>

Nongenomic action of corticosterone to calcium rise induced by high-K+ in PC12 cells / 中国应用生理学杂志

<p><b>AIM</b>To analyse the mechanism of corticosterone on the elevation of cytosolic free calcium ([Ca2+]i) induced by high-K+ in pheochromocytoma PC12 cells,</p><p><b>METHODS</b>The [Ca2+]i was real-time checked by fluorescence image system.</p><p><b>RESULTS</b>(1) When the cells were preincubated at 37 degrees C for 5 min in the presence of various concentration corticosterone and stimulated with 55 mmol/L KCl , an inhibitory effect of corticosterone on delta[Ca2+]i was observed in a concentration-dependent manner. (2) When PC12 cells were preincubated with various concentration of B-BSA at 37 degrees C for 5 min and stimulated with 55 mmol/L KCl, an inhibitory effect of B-BSA on delta[Ca2+]i was observed, which is also concentration-dependent manner. (3) The inhibitory effect of corticosterone and B-BSA could not be antagonized by RU38486 at 10(-4) mol/L. (4) cycloheximide could not block the inhibitory effect of corticosterone after pretreating cells at 10(-5) mol/L at 37 degrees C for 3 hours.</p><p><b>CONCLUSION</b>It is obvious that the locus of corticosterone action is on the plasmic membrane. The inhibitory effect of corticosterone is independent of protein synthesis and intracellular glucocorticoid receptor. The effect of corticosterone on [Ca2+]i is nongenomic action in PC12 cells.</p>

The biologic significance of nongenomic effects of glucocorticoids / 中华内分泌代谢杂志

Glucocorticoids (GC) exert a broad effect on the body and have been extensively used clinically.It is well known now that GC can act via both genomic and nongenomic mechanisms.Genomic effects of GC have been well reviewed elsewhere.Here we focus on the current understanding of nongenomic effects and discuss their biologic significance as well as the remaining problems in this field.