Neuroscience
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Several lines of evidence indicate group III metabotropic glutamate receptors (mGluRs) have systemic anti-hyperalgesic effects. We hypothesized this could occur through modulation of TRP channels on nociceptors. This study used a multifaceted approach to examine the interaction between group III mGluRs (mGluR8) and transient receptor potential ankyrin 1 (TRPA1) on cutaneous nociceptors in rats. ⋯ Taken together, these results show that group III mGluRs negatively modulate TRPA1 activity on cutaneous nociceptors. Furthermore, it is likely that this modulation occurs intracellularly at the level of the cAMP/PKA pathway. This study demonstrates that group III agonists may be effective in the treatment of mechanical hypersensitivity which can develop as a result of inflammation, nerve injury, chemotherapy and other disease states.
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Numerous intrinsic currents are known to collectively shape neuronal membrane potential dynamics, or neuronal signatures. Although how sets of currents shape specific signatures such as spiking characteristics or oscillations has been studied individually, it is less clear how a neuron's suite of currents jointly shape its entire set of signatures. Biophysical conductance-based models of neurons represent a viable tool to address this important question. ⋯ We illustrate the methodology using two example case rodent pyramidal neurons, from the lateral amygdala and the hippocampus. The methodology also helped reveal that a single-core compartment model could capture multiple neuronal properties. Such biophysical single-compartment models have potential to improve the fidelity of large network models.
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Anxiety disorders are more likely to occur in women than in men, usually emerge during adolescence and exhibit high comorbidity with alcohol use disorders (AUD). Adolescents with high levels of anxiety or heightened reactivity to stress may be at-risk for developing AUD. An approach to analyze if high levels of inborn anxiety predict greater ethanol drinking is to assess the latter variable in subjects classified as high- or low-anxiety responders. ⋯ Stress induced a significant increase in FOS immunoreactivity at the paraventricular nucleus, yet this effect was unaffected by level of anxiety response. Female adolescents with high levels of basal anxiety may be at-risk for exhibiting increased predisposition for ethanol intake and preference. The study also indicates that stress may exert differential effects on adolescent ethanol intake as a function of the level of anxiety response.
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This experiment tested the hypothesis that interlimb transfer of motor performance depends on recruitment of motor control processes that are specialized to the hemisphere contralateral to the arm that is initially trained. Right-handed participants performed a single-joint task, in which reaches were targeted to 4 different distances. While the speed and accuracy was similar for both hands, the underlying control mechanisms used to vary movement speed with distance were systematically different between the arms: the amplitude of the initial acceleration profiles scaled greater with movement speed for the right-dominant arm, while the duration of the initial acceleration profile scaled greater with movement speed for the left-non-dominant arm. ⋯ We now hypothesize that task practice with the right arm might reinforce left-hemisphere mechanisms that vary acceleration amplitude with distance, while practice with the left arm might reinforce right-hemisphere mechanisms that vary acceleration duration with distance. We thus predict that following right arm practice, the left arm should show increased contributions of acceleration amplitude to peak velocities, and following left arm practice, the right arm should show increased contributions of acceleration duration to peak velocities. Our findings support these predictions, indicating that asymmetry in interlimb transfer of motor performance, at least in the task used here, depends on recruitment of lateralized motor control processes.
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Resting-state networks (RSNs) refer to the spontaneous brain activity generated under resting conditions, which maintain the dynamic connectivity of functional brain networks for automatic perception or higher order cognitive functions. Here, Granger causal connectivity analysis (GCCA) was used to explore brain RSNs in the music frog (Babina daunchina) during different behavioral activity phases. The results reveal that a causal network in the frog brain can be identified during the resting state which reflects both brain lateralization and sexual dimorphism. ⋯ Thus we propose that this causal network maintains auditory perception during the resting state for unexpected auditory inputs as resting-state networks do in other species. These results are also consistent with the idea that females are more sensitive to auditory stimuli than males during the reproductive season. In addition, these results imply that even when not behaviorally active, the frogs remain vigilant for detecting external stimuli.