Neuroreport
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The metabotropic glutamate receptor subtype 7 (mGluR7) is presynaptically located and modulates transmitter release. An earlier study from our group demonstrated that systemic administration of N,N'-dibenzyhydryl-ethane-1,2-diamine dihydrochloride (AMN082), a selective allosteric mGluR7 agonist, attenuates the acquisition of conditioned fear measured by fear-potentiated startle. ⋯ Our data clearly show that intra-amygdala injection of AMN082 impairs fear acquisition. This finding demonstrates that amygdaloid mGluR7 controls the learning of conditioned fear.
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We describe the characterization of a partial saphenous nerve injury (PSNI) model of neuropathic pain in the mouse. PSNI resulted in significant mechanical allodynia in mice with no behavioural change to temperature stimulation. ⋯ In galanin knockout mice, PSNI failed to induce allodynia as previously reported in other neuropathic pain models. PSNI can be used to simultaneously study behavioural and neurophysiological changes in wild-type and transgenic mice.
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In event-related brain potential studies using a visual S1-S2 matching task, stimulus changes elicit change-related positivity, which reflects the detection of visual changes. To investigate the effects of attention on change detection, we tested the elicitation of change-related positivity in response to changes in color and spatial frequency under three attention conditions: (i) changes in an unattended feature at an attended location, (ii) in an attended feature at an unattended location, and (iii) in an unattended feature at an unattended location. The results suggest that stimulus changes can be detected even when both feature and spatial attention are withdrawn, but change detection can also be inhibited, which might be because of biased-competition determined by the combination of feature and spatial attention conditions.
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The evaluation of whether an outcome is good or bad is reflected in feedback-related negativity (FRN), which is an event-related brain potential (ERP) component that is elicited by bad events. It is still, however, unclear how the FRN reflects the evaluation of outcomes induced by others. ⋯ FRN was elicited not only by the losses of another in a cooperative situation but also by the gains of another in an antagonistic situation. These results indicate that FRN reflects the evaluation on the basis of one's own evaluative criteria, regardless of the monetary outcome for another.
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Randomized Controlled Trial
Theta burst stimulation of the motor cortex reduces laser-evoked pain perception.
Repetitive transcranial magnetic stimulation over the primary motor cortex (M1) was recently introduced to modulate pain perception. The aim of this double-blind cross-over study was to investigate the effect of a modified rTMS paradigm, called cTBS on experimentally induced laser-evoked pain applied over the left M1. cTBS inhibits the cortical excitability of the M1 for approximately 1 h. Subjective pain was measured using the verbal analogue scale prior to, immediately after and 30 min post-stimulation. cTBS, and not the sham stimulation resulted in a significant decrease in pain perception on both hands, accentuated on the right hand. Further studies are needed using motor cortex TBS in chronic pain to pave the way towards a therapeutic tool.