Neuroscience letters
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Neuroscience letters · Aug 2013
Facilitation of corticospinal tract excitability by transcranial direct current stimulation combined with voluntary grip exercise.
Previous studies have established that transcranial direct current stimulation (tDCS) is a powerful technique for the deliberate manipulation of the activity of human cerebral cortex. Moreover, it has also been shown that the non-exhausted voluntary motor exercise increases the excitability of corticospinal tract. ⋯ Our result showed that the combination of anodal tDCS with voluntary grip exercise produced a 2-fold increase in the amplitude of MEP as compared with single use of anodal tDCS or voluntary grip exercise. In conclusion, our result could indicate that the treatment outcomes of brain and neurorehabilitation using tDCS would be better when tDCS is combined with the appropriate method of voluntary exercise as compared with single use of tDCS.
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Neuroscience letters · Aug 2013
Mammal retinal distribution of ENKergic amacrine cells and their neurochemical features: evidence from the PPE-GFP transgenic mice.
The neuroactive peptide enkephalin (ENK) has been postulated to play important roles in modulating visual information. The retinal presence of ENKergic cells has been revealed with conventional morphological protocols targeting ENK molecule especially in avian, however, the detailed distribution of ENKergic cells and their specific neurochemical features in the mammal retina remain unclear because of the difficulties in visualizing ENKergic cells efficiently and reliably. To address this question, we took advantage of the preproenkephalin-green fluorescent protein (PPE-GFP) transgenic mice previously generated and identified in our group, and identified the neurochemical characteristics of retinal ENKergic cells. ⋯ However, some of them also utilized excitatory glutamate as the primary neurotransmitter. The present findings suggest that the retinal ENKergic cells fall into a subpopulation of amacrine cells and show predominantly inhibitory as well as less dominantly excitatory neurochemical features. Our findings offered comprehensive morphological evidence for the function of ENKergic amacrine cells of mammal species.
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Neuroscience letters · Aug 2013
Choline, an alpha7 nicotinic acetylcholine receptor agonist, alleviates hyperalgesia in a rat osteoarthritis model.
It has been suggested that activation of alpha7 nicotinic acetylcholine receptors (α7nAChR) could alleviate acute and chronic pain in various abnormal pain models. However, it is unclear whether the stimulation of α7nAChRs has anti-hyperalgesic effects on osteoarthritis. Therefore, we tested whether choline, an α7nAChR agonist, could alleviate chronic inflammatory pain in an osteoarthritis model. ⋯ Intrathecal choline increased PWT and PWL. The anti-hyperalgesic effect of intraperitoneal choline was completely blocked by methyllycaconitine when it was injected intrathecally 10 min before the choline treatment. These results show that choline could alleviate mechanical and heat hyperalgesia via spinal α7nAChR in the MIA-induced inflammation pain model.
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Neuroscience letters · Aug 2013
Cortical activation during auditory elicitation of fear and disgust: a near-infrared spectroscopy (NIRS) study.
This near infrared spectroscopy study investigated whether nonverbal human sounds representing different basic emotions are able to specifically modulate temporo-parietal cortices, involved in auditory processing and attention. Forty-three adults (19 females and 24 males) were presented with sounds from the categories fear, disgust, and neutral. ⋯ The hemodynamic responses to disgusting sounds (e.g., sniffing, diarrhea) were smaller. Our findings point to a differential neuronal sensitivity of the human brain to two basic emotion elicitors in the auditory domain.
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Neuroscience letters · Aug 2013
Mu-opioidergic modulation differs in deep and superficial wide-dynamic range dorsal horn neurons in mice.
The spinal cord dorsal horn is an important action site for morphine analgesia. Wide-dynamic range (WDR) neurons in the dorsal horn are essential to spinal pain transmission and show increased excitability after repetitive noxious drive (windup). In light of differences in mu-opioid receptor distribution and neurophysiological properties of WDR neurons between deep and superficial dorsal horn, we recorded extracellular single-unit activity of WDR neurons from deep (350-700 μm) and superficial (<350 μm) dorsal horn in C57BL/6 mice and compared their responses to spinal superfusion of morphine (0.5mM, 30 μl) and naloxone (1mM, 30 μl). ⋯ In separate experiments, spinal administration of naloxone facilitated the development of windup to 0.2 Hz stimulation in deep (n=10), but not superficial (n=8), WDR neurons. Accordingly, morphine and naloxone modulation of neuronal activity may be related to a specific effect on neuronal sensitization/plasticity in deep WDR neurons, whereas morphine inhibition may depress acute noxious inputs to superficial WDR neurons. Our study suggests that mu-opioidergic modulation may be different in deep and superficial WDR neurons.