Neuroscience
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Compared with the biological paradigms of classical conditioning, non-adaptive computational models are not capable of realistically simulating the biological behavioural functions of the hippocampal regions, because of their implausible requirement for a large number of learning trials, which can be on the order of hundreds. Additionally, these models did not attain a unified, final stable state even after hundreds of learning trials. Conversely, the output response has a different threshold for similar tasks in various models with prolonged transient response of unspecified status via the training or even testing phases. ⋯ The results of the Green model showed a significant improvement confirmed by empirical studies of different tasks. In addition, the results indicated that the model outperforms the previously published models. All the obtained results successfully and quickly attained a stable, desired final state (with a unified concluding state of either "1" or "0") with a significantly shorter transient duration.
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Vascular dementia (VD) is a major cognitive disorder originated from a blood flow disruption in the brain. This process leads to chronic cerebral ischemia that deeply affects neuronal tissues and lipid homeostasis. The understanding of cerebral lipid dynamics during chronic ischemia can reveal biomarkers and novel pharmacological targets for the treatment of VD. ⋯ Decanoic acid was increased after 30 days of BCCAO model. Partial least squares discriminant analysis (PLS-DA) could discriminate between BCCAO group and the control group, in which γ-linolenic acid (m/z 277) ion and stearic acid (m/z 283) had the highest discrimination potential. Taken together, these findings indicate that lipid dynamics are altered in chronic ischemia-induced by BCCAO in rats and indicate potential biomarkers and pharmacological targets for VD.
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Neurons from several brain regions resonate in the theta frequency range (4-12 Hz), displaying a higher voltage response to oscillatory currents at a preferred 'resonant' frequency (fR). Subthreshold resonance could influence spiking and contribute to the selective entrainment of neurons during the network oscillatory activity that accompanies several cognitive processes. Neurons from different regions display resonance in specific theta subranges, suggesting a functional specialization. ⋯ In all the neurons studied, fR inversely correlated with the effective input resistance (Rin), a measurable variable that depends on passive and active membrane features. We showed that resonance can be adjusted by manipulations mimicking naturally occurring processes, as the incorporation of a virtual constant conductance or cell depolarization, in a way that preserves the fR-Rin relationship. The modulation of frequency selectivity influences firing by shifting spike frequency and timing, which could influence neuronal communication in an active network.
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Estradiol not only participates in the regulation of energy metabolism in adulthood, but also during the first stages of life as it modulates the alterations induced by under- and over-nutrition. The objectives of the present study were to determine: 1) If estradiol is involved in the normal programming of energy metabolism in rats; 2) If there is a specific window of time for this programming and 3) If males and females are differentially vulnerable to the action of this hormone. Estrogen receptors (ER) α, ERβ and GPER were blocked by their specific antagonists MPP, PHTPP and G15, respectively, from postnatal day (P) 1 (the day of birth) to P5 or from P5 to P13. ⋯ The blocking of ERs from P1 to P5 only affected plasma estradiol levels in females. The present results indicate programming actions of estradiol from P5 to P13 on body weight in male and POMC expression in female rats and emphasize the importance of including both sexes in metabolic studies. It is necessary to unravel the mechanisms that underlie the actions of estradiol on food intake, both during development and in adulthood, and to determine how this programming differentially takes place in males and females.
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After ischemic stroke, the degenerated myelin caused by ischemic injury cannot be rapidly cleared away by microglia and interferes with the recovery process. Complement receptor 3 (CR3, CD11b/CD18), belonging to β2 integrin family primarily expressed in phagocytes, is involved in the microglial phagocytosis of myelin debris. We previously found that pseudoginsenoside-F11 (PF11), an ocotillol-type saponin, exerts neuroprotective effects against ischemic stroke and neuroinflammation. ⋯ Meanwhile, PF11 strengthened the OGD-activated RhoA/ROCK signaling associated with the internalization during myelin debris phagocytosis through CR3. Consistently, the anti-CD11b mAb could markedly attenuated the nrueoprotective effects of PF11 (12 mg/kg, i.v.) on infarction and brain edema, neurological functions and loss of neurons of pMCAO rats. These findings suggest that PF11 accelerates the phagocytosis of myelin debris by microglia mainly through CR3, which may likely contribute to its neuroprotection against ischemic stroke.