Neuroscience
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When simultaneously performing asymmetrical movements with both hands, there is a tendency for the action of one limb to interfere with control of the other. Little is known about how sensory feedback influences interference. We conducted two experiments to determine how manipulating force feedback and visual feedback alter bimanual coordination during center-out reaching. ⋯ In the adaptive experiment, interference increased with an increase in the force demands for movement in a dose-response fashion (i.e., the higher the resistive force, the larger the interference), but this result did not hold generally for the non-adaptive experiment. Our results indicate that adapting to a visuomotor perturbation may increase sensitivity to feedback gains, including to sensory information not present in the perturbation. Additionally, interference may reflect the application of an explicit strategy used for one limb to control the other, and the addition of an implicit adapting process may bolster this communication of motor information across motor cortices.
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The left posterior inferior frontal gyrus in the prefrontal cortex is a key region for phonological aspects of language processing. A previous study has shown that alpha-tACS over the prefrontal cortex applied before task processing facilitated phonological decision-making and increased task-related theta power. However, it is unclear how alpha-tACS affects phonological processing when applied directly during the task. ⋯ As an unexpected finding, 16.18 Hz significantly impaired task accuracy relative to sham stimulation, without affecting response speed. There was no significant difference in phonological task performance between 10 Hz and 16.18 Hz tACS or between 10 Hz and sham stimulation. Our results support the functional relevance of the left prefrontal cortex for phonological decisions and suggest that online beta-tACS may modulate language comprehension.
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Opioid use by women during pregnancy has risen dramatically since 2004, accompanied by a striking increase in the prevalence of neonatal opioid withdrawal syndrome (NOWS) and other long-term neurological deficits. However, the mechanisms underlying the impact of prenatal opioid exposure on fetal neurodevelopment are largely unknown. To translate from the clinical presentation, we developed a novel mouse model to study the neurodevelopmental consequences of maternal opioid use and management. ⋯ However, adolescent offspring exposed to maternal opioid use during pregnancy exhibited hyperactivity in late adolescence. Remarkably, we also show increased generation of dopaminergic neurons within the ventral tegmental area (VTA) of mice exposed to prenatal opioids. These data provide critical evidence of teratogenic effects of opioid use during pregnancy and suggest a causal relationship between maternal opioid use and neurodevelopmental/behavioral anomalies in adolescence.
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Dual orexinergic antagonists (DORAs) have been recently developed as a pharmacotherapy alternative to established hypnotics. Hypnotics are largely evaluated in preclinical rodent models in the dark/active period yet should be ideally evaluated in the light/inactive period, analogous to when sleep disruption occurs in humans. We describe here the hypnotic efficacy of DORA-22 in rodent models of sleep disturbance produced by cage changes in the light/inactive period. ⋯ EEG measures indicated that all DORA-22 doses largely promoted sleep in the first hour. The lowest dose (1 mg/kg) did not decrease sleep onset latency at the six-hour timepoint, suggesting no residual hypersomnolence. We described here DORA-22 hypnotic efficacy during the normal sleep period of nocturnal rats, and demonstrate that well-chosen (low) hypnotic doses of DORA-22 may be hypnotically effective yet have minimal lingering effects.
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Subcommissural organ (SCO)-spondin is a brain-specific glycoprotein produced during embryogenesis, that strongly contributes to neuronal development. The SCO becomes atrophic in adults, halting SCO-spondin production and its neuroprotective functions. Using rat and human neuronal cultures, we evaluated the neuroprotective effect of an innovative peptide derived from SCO-spondin against glutamate excitotoxicity. ⋯ The neuroprotective effect of NX210c was confirmed in human cortical neurons via the reduction of lactate dehydrogenase release and recovery of normal basal levels of apoptotic cells. Together, these results show that NX210 and NX210c protect against glutamate neurotoxicity through common and distinct mechanisms of action and that, most often, NX210c is more efficient than NX210. Proof of concept in central nervous system animal models are under investigation to evaluate the neuroprotective action of SCO-spondin-derived peptide.