Neuroscience letters
-
Neuroscience letters · Aug 2016
The neural mechanism of biomechanical constraints in the hand laterality judgment task: A near-infrared spectroscopy study.
The mental rotation (MR) task is defined as a discrimination task between mirror-reversed images involving discrepancy in angular orientation. Various studies have shown that the MR task likely causes mental imagery, that is, visual and/or motor imagery, depending on stimulus types. When figures of rotated hands are presented to be identified as a left or right hand, reaction times (RTs) usually show an effect of biomechanical constraints (BC): a hand in a position difficult to reach with a real movement results in longer RTs. ⋯ In the HLJ task, both the RTs and the activity of the left superior parietal lobe (SPL) showed an interaction between Hand (left, right) and Orientation (135°, 225°) i.e., the BC effect, but not in the character judgment task. More specifically, in the analysis of BC-related activity of SPL, although the Hand×Orientation interaction was significant, the left SPL for the left hand significantly increased from 135° to 225°, but the reversed increase (from 225° to 135°) was not found for the right hand. These results suggest that left SPL is involved in the BC effect and NIRS differentiates left hand awkwardness of right-hander in the HLJ task.
-
Neuroscience letters · Jul 2016
Effects of left primary motor and dorsolateral prefrontal cortex transcranial direct current stimulation on laser-evoked potentials in migraine patients and normal subjects.
Migraine is characterized by an altered cortical excitability. Because transcranial direct current stimulation (tDCS) can change brain activity noninvasively, it is possible to hypothesize its efficacy in modulating pain in migraine. In this study, we compared the effects of tDCS of the left primary motor cortex (M1) and left dorsolateral prefrontal cortex (DLPFC) both on subjective pain and on evoked responses induced by laser stimulation (LEPs). ⋯ We did not find significant acute changes in LEPs parameters and pain perception among subjects who received tDCS of both M1 and DLPFC. After DLPFC tDCS, we observed a significant increase of N2-P2 component habituation in migraine patients while M1 stimulation reduced it. These findings may suggest a modulation of abnormal pain processing induced by DLPFC and M1 anodal tDCS and outline the need for future investigations exploring the possible neuronal plasticity changes supporting the clinical effect on migraine.
-
Neuroscience letters · Jul 2016
Up-regulation of CXCL1 and CXCR2 contributes to remifentanil-induced hypernociception via modulating spinal NMDA receptor expression and phosphorylation in rats.
It is commonly known that remifentanil exposure during anesthesia might cause postoperative hyperalgesia and promote nociceptive sensitization, but specific mechanisms remain elusive. Recently, chemokine CXCL1 is considered to be involved in inflammatory and neuropathic pain, simultaneously, CXCL1 might facilitate nociceptive process by increasing of NMDA receptor activity. Several studies have also reported that NMDA receptor activation has been associated with development of remifentanil-induce hypernociception (RIH). However, whether CXCL1 could contribute to RIH in rats remains not understood. ⋯ These findings indicated that up-regulation of CXCL1 and CXCR2 might contribute to RIH via modulating spinal NR2B-containing NMDA receptor expression and phosphorylation in rats.
-
Neuroscience letters · Jun 2016
ReviewEpigenetic changes following traumatic brain injury and their implications for outcome, recovery and therapy.
Traumatic brain injury (TBI) contributes to nearly a third of all injury-related deaths in the United States. For survivors of TBI, depending on severity, patients can be left with devastating neurological disabilities that include impaired cognition or memory, movement, sensation, or emotional function. ⋯ Evidence from recent studies support the involvement of epigenetic mechanisms such as DNA methylation, chromatin post-translational modification, and miRNA regulation of gene expression in the post-injured brain. In this review, we discuss studies that have assessed epigenetic changes and mechanisms following TBI, how epigenetic changes might not only be limited to the nucleus but also impact the mitochondria, and the implications of these changes with regard to TBI recovery.
-
Neuroscience letters · Jun 2016
L5 spinal nerve axotomy induces sensitization of cutaneous L4 Aβ-nociceptive dorsal root ganglion neurons in the rat in vivo.
Partial nerve injury often leads to peripheral neuropathic pain (PNP), a major health problem that lacks effective drug treatment. PNP is characterized by ongoing/spontaneous pain, and hypersensitivity to noxious (hyperalgesia) and innocuous (allodynia) stimuli. ⋯ Compared with control, cutaneous L4 Aβ-nociceptive DRG neurons in SNA rats (that developed mechanical hypersensitivity) exhibited sensitization indicated by: a) decreased mean mechanical threshold (from 57.8±7.1 to 10.3±1.7mN), b) decreased mean dorsal root electrical threshold (from 11.4±0.7 to 4.3±0.4V), c) increased mean response to a suprathreshold mechanical stimulus (from 18.5±1.8 to 34±3.7spikes/sec) and d) an obvious, but non-significant, increase in the incidence of ongoing/spontaneous activity (from 3% to 18%). These findings suggest that cutaneous L4 Aβ-nociceptors also become sensitized after L5 SNA, and that sensitization of this subclass of A-fiber nociceptors may contribute both directly and indirectly to nerve injury-induced PNP.