Neuroscience
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Conventional transcutaneous electrical nerve stimulation (TENS) has been reported to effectively alleviate chronic pain, including phantom limb pain (PLP). Recently, literature has focused on modulated TENS patterns, such as pulse width modulation (PWM) and burst modulation (BM), as alternatives to conventional, non-modulated (NM) sensory neurostimulation to increase the efficiency of rehabilitation. However, there is still limited knowledge of how these modulated TENS patterns affect corticospinal (CS) and motor cortex activity. ⋯ The results revealed significant facilitation of CS excitability following the PWM intervention. We also found an increase in the volume of the motor cortical map following the application of the PWM and NM (40 Hz). Although PLP alleviation has been reported to be associated with an enhancement of corticospinal excitability, the efficiency of the PWM intervention to induce pain alleviation should be validated in a future clinical study in amputees with PLP.
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The importance of morphological segmentation for reading has been shown in numerous behavioral studies in children and adults. However, little is known about developmental changes in the neural basis of morphological processing. In addition to effects of age and reading skill, morphological processing during reading may be affected by the morphological structure of the language and the transparency of its orthography. ⋯ These results diverge from a previous finding in adults, showing left frontal activation in the non-transparent script with the same stimuli. These results support the early sensitivity of young Hebrew readers to the rich morphological structure of their language but suggest a developmental change in the role of morphological processes during reading. While in adults morpho-phonological segmentation during reading may compensate for orthographic opacity, morphological processes in children may rely more on semantic aspects, and are enhanced by orthographic transparency.
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The hypothalamic paraventricular nucleus (PVN) plays a key role in hypertension, however the signaling pathways that contribute to the adaptability of the PVN during hypertension are uncertain. We present evidence that signaling at the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) GluA1 receptor contributes to increased blood pressure in a model of neurogenic hypertension induced by 14-day slow-pressor angiotensin II (AngII) infusion in male mice. It was found that AngII hypertension was associated with an increase in plasma membrane affiliation of GluA1, but decreased GluA2, in dendritic profiles of PVN neurons expressing the TNFα type 1 receptor, a modulator of AMPA receptor trafficking. ⋯ A further functional role for GluA1 in the PVN was demonstrated by the attenuated hypertensive response following silencing of GluA1 in the PVN of AngII-infused male mice. In female mice, AngII-infusion did not impact blood pressure or plasma membrane localization of GluA1. Post-translational modifications that increase the plasma membrane localization of AMPA GluA1 and heighten the rapid excitatory signaling actions of glutamate in PVN neurons may serve as a molecular substrate underlying sex differences in hypertension.
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It is well established that the damaging effects of drugs of abuse, such as cocaine, can extend beyond the user to their offspring. While most preclinical models of the generational effects of cocaine abuse have focused on maternal effects, we, and others, report distinct effects on offspring sired by fathers treated with cocaine prior to breeding. However, little is known about the effects of paternal cocaine use on first generation (F1) offspring's social behaviors. ⋯ Female F1 behavior was similarly examined, but there were no effects of paternal cocaine. Cocaine-sired male mice also exhibited localized oxytocin receptor expression differences vs. controls in several brain regions regulating social behavior. These results provide evidence for effects of paternal cocaine exposure on social behaviors in male offspring with associated alterations in central oxytocin transmission.
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Several studies have reported similar neural modulations between brain areas of the frontal cortex, such as the dorsolateral prefrontal (DLPFC) and the premotor dorsal (PMd) cortex, in tasks requiring encoding of the abstract rules for selecting the proper action. Here we compared the neuronal modulation of the DLPFC and PMd of monkeys trained to choose the higher rank from a pair of abstract images (target item), selected from an arbitrarily rank-ordered set (A > B > C > D > E > F) in the context of a transitive inference task. Once acquired by trial-and-error, the ordinal relationship between pairs of adjacent images (i.e., A > B; B > C; C > D; D > E; E > F), monkeys were tested in indicating the ordinal relation between items of the list not paired during learning. ⋯ This result is in line with the hypothesis that after learning, the monkeys built an abstract mental representation of the ranked items, where rank comparisons correspond to the items' position comparison on this representation. In both brain areas, we observed higher neuronal activity when the target item appeared in a specific location on the screen with respect to the opposite position and that this difference was particularly enhanced at lower degrees of difficulty. By comparing the time evolution of the activity of the two areas, we observed that the neural encoding of target item spatial position occurred earlier in the DLPFC than in the PMd.