Neuroscience
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Recent studies have suggested that resting-state brain functional connectivity (RSFC) has the potential to discriminate among individuals in a population. These studies mostly utilized a pattern of RSFC obtained from one scan to identify a given individual from the set of patterns obtained from the second scan. However, it remains unclear whether the discriminative ability would change with the extension of the time span between the two brain scans. ⋯ We found that although the accuracies were detectable at above-chance levels, the discriminative accuracies showed a significant decrease (F = 17.87, p < 0.01) along with the extension of brain imaging time span, from over 90% within one month to 66% at 2-3 years. Furthermore, the decreasing trend was robust and not dependent on the training set or analysis method. Therefore, we suggest that the discriminative ability of RSFC in identifying individuals should be susceptible to the length of time between brain scans.
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When processing repeated stimuli, the neural response is attenuated (i.e., neural adaptation) and performance seems to be facilitated; however, this neural adaptation negatively influences the subsequent processing of novel stimuli. The present study was designed to test whether and how temporal expectations reduce neural adaptation and attenuate the negative influence of neural adaptation on subsequent novel problem solving. Temporal expectations were experimentally manipulated by asking participants to solve a novel problem following three to five repeated problems, generating the expectation of repeated events in the first three serial positions as well as that of novel events in the fourth to sixth serial positions. ⋯ Regarding the novel events, the conflict monitoring- and resolution-related N400, P600 and LNC amplitudes decreased with decreased neural adaptation. These results indicate that the expectation of novel events attenuate the negative influence of neural adaptation on the subsequent processing of novel events. This study provides new insight into alleviating the constraints imposed by frequently used knowledge on the processing of novel stimuli.
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Acute pain alters motor unit discharge properties in muscles that are painful or influence loading of painful structures. Less is known about the changes in discharge when pain is induced in distant tissues that are unable or have limited capacity to modify the load of the contracting muscle. We aimed to determine whether acute experimental pain alters quadriceps motor unit discharge when pain is induced in; (i) a muscle that is unlikely to be mechanically influenced by modified quadriceps activity (tibialis anterior: TA), or (ii) the antagonist muscle (biceps femoris: BF). ⋯ Despite maintained force, discharge rate of quadriceps motor units was lower during Pain than Control conditions for TA and BF trials (both P < 0.001). Redistribution of motor unit activity was observed; some units were recruited in control or pain but not both. As modified quadriceps motor unit discharge has limited/no potential to modify load in the painful tissue to protect the painful part, the findings might support an alternative hypothesis that activity is redistributed to larger motor units.
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A possible role for the brain β-endorphin system in memory modulation was proposed by Ivan Izquierdo more than 30 years ago. Along with pharmacologic evidence of the effects of morphine and naloxone administered immediately after training in avoidance tasks and with the demonstration of medial-basal hypothalamus β-endorphin release after novelty detection, it was hypothesized that an endogenous opioid state present in the labile period of consolidation will be part of the memory of the newly acquired information. ⋯ In this review some of the original papers in the subject are revisited. Recent studies on the memory beneficial effects of novelty, both in animal models and in humans, indicate this is line of investigation is worth of pursuing and demonstrate the importance of the seminal work of Ivan Izquierdo in the field of memory modulation.
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Circular RNAs (circRNAs), forming a covalently closed loop, are identified as a special subgroup of non-coding RNAs. Herein, we investigated the function and underlying mechanism of circXRCC5, generated from the XRCC5 gene, in glioma progression. Bioinformatics analysis was employed to determine the genomic information of circXRCC5 derived from XRCC5 pre-mRNA. ⋯ There was a reciprocal negative feedback between circXRCC5 and miR-490-3p in an Argonaute2-dependent manner. Moreover, circXRCC5 acted as a sponge of miR-490-3p to regulate the expression of downstream target gene XRCC5, thus activating the transcription of CLC3, which fostered the progression of glioma. Collectively, circXRCC5 promoted glioma progression via the miR-490-3p/XRCC5/CLC3 ceRNA network, providing a novel prognostic biomarker and a prospective target for glioma treatment.