Neuroreport
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The age effect on classical eyeblink conditioning in unrestrained mice (C57BL/6J strain) was evaluated. Mice were trained at one of three age periods (8, 45-50 or 85-90 weeks). ⋯ On the other hand, in the trace paradigm with a stimulus-free trace interval of 500 ms, significant deficits became apparent at the age of 45-50 weeks. These results indicate that trace eyeblink conditioning is more susceptible to age-related deterioration of memory in mice than delay eyeblink conditioning.
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Our previous work has shown that PSD-95/SAP90 is required for NMDA receptor-mediated thermal hyperalgesia. To address the role of PSD-95/SAP90 in chronic pain, the present study investigated the effect of the deficiency of PSD-95/SAP90 on nerve injury-induced neuropathic pain. ⋯ The intrathecal administration of antisense oligodeoxynucleotide specifically against PSD-95/SAP90, but not sense or missense oligodeoxynucleotide, dose-dependently delayed the onset of tactile allodynia and thermal hyperalgesia. These results suggest that PSD-95/SAP90 might be involved in the central mechanisms of the development of chronic neuropathic pain.
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The tetrodotoxin-resistant voltage-gated sodium channel Nav 1.8 is expressed only in nociceptive sensory neurons. This channel has been proposed to contribute significantly to the sensitization of primary sensory neurons after injury. ⋯ The results from the present studies reveal that Nav 1.8 is a necessary mediator of NGF-induced thermal hyperalgesia but is not essential for PGE2-evoked hypersensitivity. Neuropathic pain behaviours were unchanged in Nav 1.8 -/- mice indicating that this channel is not involved in the alteration of sensory thresholds following peripheral nerve injury.
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Randomized Controlled Trial Clinical Trial
Pain relief induced by repetitive transcranial magnetic stimulation of precentral cortex.
Chronic electrical stimulation of the precentral (motor) cortex using surgically implanted electrodes is performed to treat medication-resistant neurogenic pain. The goal of this placebo-controlled study was to obtain such antalgic effects by means of a non-invasive cortical stimulation using repetitive transcranial magnetic stimulation (rTMS). ⋯ A significant decrease in the mean pain level of the series was obtained only after 10 Hz rTMS. This study shows that a transient pain relief can be induced by 10 Hz rTMS of the motor cortex in some patients suffering from chronic neurogenic pain.
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We used signals from tactile mechanoreceptors in the skin of the index finger, recorded with an implanted cuff electrode, to automatically control grasp force in a hand grasp neuroprosthesis. Phasic events in the recorded nerve signal, related to mechanical events on the skin, were used to adjust electrical stimulation of hand muscles without any prior knowledge about muscle strength and properties of a held object. ⋯ When using the neuroprosthesis with feedback from natural sensors, the average grasp force could be reduced in comparison to not using feedback. Reducing grasp force is considered a major factor to decrease muscle fatigue, allowing a prolonged use of the hand grasp neuroprosthesis.