Rapid alternate monocular deprivation does not affect binocular balance and correlation in human adults.

Recent studies show that the human adult visual system exhibits neural plasticity. For instance, short-term monocular deprivation shifts the eye dominance in favor of the deprived eye. This phenomenon is believed to occur in the primary visual cortex by reinstating neural plasticity. However, it is unknown whether the changes in eye dominance after monocularly depriving the visual input can also be induced by alternately depriving both eyes. In this study, we found no changes in binocular balance and interocular correlation sensitivity after a rapid (7 Hz), alternate and monocular deprivation for one hour in adults. Therefore, the effect of short-term monocular deprivation cannot seem to be emulated by alternately and rapidly depriving both eyes.Significance statementPrevious work has shown that short-term binocular function disruption, which its most extreme form is monocular deprivation, could induce neural plasticity in adult visual system. In this study, we found a balanced deprivation of binocular function could not induce a neuroplastic change in human adults. It appears that ocular dominance plasticity in human adults is unique in so far as it is only driven by an input imbalance not balanced deprivation of binocular function.

Within-Trial Persistence of Learned Behavior as a Dissociable Behavioral Component in Hippocampus-Dependent Memory Tasks: A Potential Postlearning Role of Immature Neurons in the Adult Dentate Gyrus.

The term "memory strength" generally refers to how well one remembers something. But more precisely it contains multiple modalities, such as how easily, how accurately, how confidently and how vividly we remember it. In human, these modalities of memory strength are dissociable. In this study, we asked whether we can isolate a behavioral component that is dissociable from others in hippocampus-dependent memory tasks in mice, which potentially reflect a modality of memory strength. Using a virus-mediated inducible method, we ablated immature neurons in the dentate gyrus in mice after we trained the mice with hippocampus-dependent memory tasks normally. In memory retrieval tests, these ablated mice initially showed intact performance. However, the ablated mice ceased learned behavior prematurely within a trial compared with control mice. In addition, the ablated mice showed shorter duration of individual episodes of learned behavior. Both affected behavioral measurements point to persistence of learned behavior. Thus, the effect of the postlearning manipulation showed dissociation between initial performance and persistence of learned behavior. These two behavioral components are likely to reflect different brain functions and be mediated by separate mechanisms, which might represent different modalities of memory strength. These simple dissociable measurements in widely used behavioral paradigms would be useful to understand detailed mechanisms underlying the expression of learned behavior and potentially different modalities of memory strength in mice. We also discuss a potential role that immature neurons in the dentate gyrus may play in persistence of learned behavior.

Efficacy of erythropoietin-pretreated mesenchymal stem cells in murine burn wound healing: possible in vivo transdifferentiation into keratinocytes.

BACKGROUND: Stem cells have shown promising potential to treat burn wounds. Erythropoietin was capable of promoting in vitro transdifferentiation of mesenchymal stem cells (MSCs). The aim of the study was to investigate possible role of erythropoietin-pretreated mesenchymal stem cells (EPOa/MSCs) in burn wounds healing and to evaluate its in vivo differentiation into keratinocytes. MATERIALS AND METHODS: Forty rats were utilised in this study divided into four groups (n = 10 for each). Control group (I), burn group (II), burn + MSCs, group (III), burn + EPOa/MSCs. 1 × 106 cells were injected locally for each 1 cm² of burn areas. Burn areas were followed-up morphologically. After 21 days of the experiment, the rats were euthanised, skin specimens were assessed biochemically, histologically and immunohistochemically. RESULTS: EPOa/MSCs enhanced significantly (p < 0.05) burn wound vimentin gene expression and level of interleukin (IL)-10 while decreased IL-1 and COX2 as compared to the burn group. Histologically, EPOa/MSCs improved epithelialisation despite stem cells' differentiation into keratinocytes was rarely detected by PKH26 red fluorescence. EPOa/MSCs promoted angiogenesis as detected by significant increase in VEGF and PDGF immunoexpression as compared to burn group. CONCLUSIONS: EPOa/MSCs may improve burn wound healing, probably through anti-inflammatory, immunomodulatory and angiogenic action. However, in vivo transdifferentiation into keratinocytes was rarely detected.

Endogenous interleukin-1ß in neuropathic rats enhances glutamate release from the primary afferents in the spinal dorsal horn through coupling with presynaptic N-methyl-D-aspartic acid receptors.

Excessive activation of glutamate receptors and overproduction of proinflammatory cytokines, including interleukin-1ß (IL-1ß) in the spinal dorsal horn, are key mechanisms underlying the development and maintenance of neuropathic pain. In this study, we investigated the mechanisms by which endogenous IL-1ß alters glutamatergic synaptic transmission in the spinal dorsal horn in rats with neuropathic pain induced by ligation of the L5 spinal nerve. We demonstrated that endogenous IL-1ß in neuropathic rats enhances glutamate release from the primary afferent terminals and non-NMDA glutamate receptor activities in postsynaptic neurons in the spinal dorsal horn. Myeloid differentiation primary response protein 88 (MyD88) is a mediator used by IL-1ß to enhance non-NMDA glutamate receptor activities in postsynaptic neurons in the spinal dorsal horn. Presynaptic NMDA receptors are effector receptors used by the endogenous IL-1ß to enhance glutamate release from the primary afferents in neuropathic rats. This is further supported by the fact that NMDA currents recorded from small neurons in the dorsal root ganglion of normal rats are potentiated by exogenous IL-1ß. Furthermore, we provided evidence that functional coupling between IL-1ß receptors and presynaptic NMDA receptors at the primary afferent terminals is mediated by the neutral sphingomyelinase/ceramide signaling pathway. Hence, functional coupling between IL-1ß receptors and presynaptic NMDA receptors at the primary afferent terminals is a crucial mechanism leading to enhanced glutamate release and activation of non-NMDA receptors in the spinal dorsal horn neurons in neuropathic pain conditions. Interruption of such functional coupling could be an effective approach for the treatment of neuropathic pain.