Neuroscience
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Working memory (WM) is a core element of temporal information processing, but little is known about the internal representation and neuronal underpinnings of the duration maintenance in WM. The neural oscillations during maintenance of duration in WM were examined using electroencephalogram (EEG) recordings. ⋯ The results suggest that alpha activity is involved in duration maintenance in WM. Our study provides electrophysiological evidence that different internal representations are retained in WM for durations below and above about 3s.
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We have analyzed the expression pattern of a novel serine/threonine kinase gene Ulk4 during forebrain development in Xenopus laevis. To this aim, we firstly cloned a Ulk4 cDNA fragment from X.laevis and generated a RNA probe that was used for its detection by in situ hybridization. Throughout development xUlk4 expression was detected along the ventricular (vz) and subventricular zones (svz) of all forebrain regions, with the exception of the vz of the striatum. ⋯ We have also found minor expression of xUlk4 in some DCX- or MAP2-positive cells but not in TH-positive neurons. These findings suggest that Ulk4 may play roles in neural stem/progenitor cells during neurogenesis both in development and in the adulthood, in migrating cells as well as in cells committed to neuronal fate in Xenopus. Moreover, the results obtained in this study argue for an involvement of Ulk4 in the control of the neuroendocrine homeostatic functions in the brain.
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Although the impact of aging on the function of the central nervous system is known, only a limited amount of information is available about accompanying changes affecting the cellular composition of the brain and spinal cord. In the present work we used the isotropic fractionator method to reveal aging-associated changes in the numbers of neuronal and non-neuronal cells harbored by the brain and spinal cord. The experiments were performed on 15-week, 7-month, 13-month, and 25-month-old female mice. ⋯ The number of proliferating cells showed a marked age-dependent decrease in the hippocampus, olfactory bulb, and rest of the brain. In contrast, the number of Ki-67-positive cells increased with age in both the cerebellum and spinal cord. In conclusion, aging-dependent changes affecting the cellular composition of the mouse central nervous system are present but they are diverse and region-specific.
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Pain patients who are nicotine dependent report a significantly increased incidence and severity of pain intensity. The goal of this study was to determine the effects of prolonged nicotine administration on inflammatory proteins implicated in the development of peripheral and central sensitization of the trigeminal system. Behavioral, immunohistochemical, and microarray studies were utilized to investigate the effects of nicotine administered daily for 14 days via an Alzet® osmotic pump in Sprague Dawley rats. ⋯ Similarly, levels of eleven cytokines were significantly elevated with the largest increase in expression of TNF-α. Levels of PKA, p-ERK, and p-JNK in trigeminal ganglion neurons were increased by nicotine. Our findings demonstrate that prolonged systemic administration of nicotine promotes sustained behavioral and cellular changes in the expression of key proteins in the spinal trigeminal nucleus and trigeminal ganglion implicated in the development and maintenance of peripheral and central sensitization.
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Menopause can cause cognitive decline. Hormone Replacement Therapy (HRT) is the most effective treatment for the climacteric symptoms. However, its cognitive effect has not been well clarified, especially for the progestin component. ⋯ DG combined with E2 could ameliorate cognition in adult rats with uterus protection and without breast harm. The cognitive-improve effects were more remarkable for the adult rats than the aged ones. The findings support the potential clinical application of dydrogesterone combined with estrogen in preventing cognitive decline, especially for the early iatrogenic menopausal women.