Ventromedial Thalamus-Projecting DCN Neurons Modulate Associative Sensorimotor Responses in Mice / 神经科学通报·英文版

The deep cerebellar nuclei (DCN) integrate various inputs to the cerebellum and form the final cerebellar outputs critical for associative sensorimotor learning. However, the functional relevance of distinct neuronal subpopulations within the DCN remains poorly understood. Here, we examined a subpopulation of mouse DCN neurons whose axons specifically project to the ventromedial (Vm) thalamus (DCNVm neurons), and found that these neurons represent a specific subset of DCN units whose activity varies with trace eyeblink conditioning (tEBC), a classical associative sensorimotor learning task. Upon conditioning, the activity of DCNVm neurons signaled the performance of conditioned eyeblink responses (CRs). Optogenetic activation and inhibition of the DCNVm neurons in well-trained mice amplified and diminished the CRs, respectively. Chemogenetic manipulation of the DCNVm neurons had no effects on non-associative motor coordination. Furthermore, optogenetic activation of the DCNVm neurons caused rapid elevated firing activity in the cingulate cortex, a brain area critical for bridging the time gap between sensory stimuli and motor execution during tEBC. Together, our data highlights DCNVm neurons' function and delineates their kinematic parameters that modulate the strength of associative sensorimotor responses.

Hippocampal Interneurons are Required for Trace Eyeblink Conditioning in Mice / 神经科学通报·英文版

While the hippocampus has been implicated in supporting the association among time-separated events, the underlying cellular mechanisms have not been fully clarified. Here, we combined in vivo multi-channel recording and optogenetics to investigate the activity of hippocampal interneurons in freely-moving mice performing a trace eyeblink conditioning (tEBC) task. We found that the hippocampal interneurons exhibited conditioned stimulus (CS)-evoked sustained activity, which predicted the performance of conditioned eyeblink responses (CRs) in the early acquisition of the tEBC. Consistent with this, greater proportions of hippocampal pyramidal cells showed CS-evoked decreased activity in the early acquisition of the tEBC. Moreover, optogenetic suppression of the sustained activity in hippocampal interneurons severely impaired acquisition of the tEBC. In contrast, suppression of the sustained activity of hippocampal interneurons had no effect on the performance of well-learned CRs. Our findings highlight the role of hippocampal interneurons in the tEBC, and point to a potential cellular mechanism subserving associative learning.

Neuronal Activity in the Cerebellum During the Sleep-Wakefulness Transition in Mice / 神经科学通报·英文版

Cerebellar malfunction can lead to sleep disturbance such as excessive daytime sleepiness, suggesting that the cerebellum may be involved in regulating sleep and/or wakefulness. However, understanding the features of cerebellar regulation in sleep and wakefulness states requires a detailed characterization of neuronal activity within this area. By performing multiple-unit recordings in mice, we showed that Purkinje cells (PCs) in the cerebellar cortex exhibited increased firing activity prior to the transition from sleep to wakefulness. Notably, the increased PC activity resulted from the inputs of low-frequency non-PC units in the cerebellar cortex. Moreover, the increased PC activity was accompanied by decreased activity in neurons of the deep cerebellar nuclei at the non-rapid eye-movement sleep-wakefulness transition. Our results provide in vivo electrophysiological evidence that the cerebellum has the potential to actively regulate the sleep-wakefulness transition.

Expression of insulin in the brain tissue of rats after scald / 中华烧伤杂志

<p><b>OBJECTIVE</b>To observe the expression of insulin in the brain tissue of rat after scald.</p><p><b>METHODS</b>Fifteen Wistar rats subjected to 30% TBSA scald were enrolled in the study. Zamboni fixating solution was infused into left ventricle and the brain tissue was harvested at 4, 12 and 24 post-scald hours (PSH) for the detection of insulin expression with fluorescent immunohistochemistry, with 5 rats at each time-point. Another group of 10 rats were enrolled as controls.</p><p><b>RESULTS</b>There exhibited no obvious insulin expression in the brain tissue of rats in the control group. Insulin immune responsive positive cells were detected in the olfactory bulb and cerebral cortex of rats at 4 PBH. These cells were big with oval and fusiform shape, big, round, transparent nuclei, and prominent processes. The positive insulin substance was mainly distributed in cytoplasm, and some in the processes of cells. No insulin immune-responsive cells were observed in rat brain tissue at 12 and 24 PSH.</p><p><b>CONCLUSION</b>The brain have the potentiality of self-biosynthesis of insulin, but very little of synthesized insulin exists in normal states, but the amount increases after scald.</p>

Effects of sin-1 on growth and cytoskeleton of endothelial cells in vitro / 第三军医大学学报

Objective　To investigate the mechanism affecting on permeability of vascular endothelial cell by nitric oxide (NO). Methods　Series concentration of sin-1（a donor of NO） were added to ECV 304, a cell line of human umbilical vein endothelium. Cell growth and expression of f-actin, a cytoskeleton protein were observed. Results　Cell growth was inhibited with a dose from 6.25 to 100 μmol/L and was caused to death at the concentration of 50 to 100 μmol/L by sin-1. The expression of f-actin was suppressed obviously after cultured with 100 μmol/L sin-1 for 4 hours. Conclusion　It suggests that anomaly increased NO can increase permeability of blood vessels by suppressing the expression of f-actin, inhibiting cell growth or even resulting in cell death.

Effects of sin-1 on growth and cytoskeleton of endothelial cells in vitro / 第三军医大学学报

Objective　To investigate the mechanism affecting on permeability of vascular endothelial cell by nitric oxide (NO). Methods　Series concentration of sin-1（a donor of NO） were added to ECV 304, a cell line of human umbilical vein endothelium. Cell growth and expression of f-actin, a cytoskeleton protein were observed. Results　Cell growth was inhibited with a dose from 6.25 to 100 μmol/L and was caused to death at the concentration of 50 to 100 μmol/L by sin-1. The expression of f-actin was suppressed obviously after cultured with 100 μmol/L sin-1 for 4 hours. Conclusion　It suggests that anomaly increased NO can increase permeability of blood vessels by suppressing the expression of f-actin, inhibiting cell growth or even resulting in cell death.