European journal of pain : EJP
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The ability to detect facial expressions of pain is crucial in eliciting prosocial behaviors towards the individual experiencing pain. Previous studies have shown that the sufferers' gender can affect the observers' explicit judgment of the pain face, thus suggesting its possible influence on pain decoding. The present study investigates whether the sufferer's gender affects the observer's reflexive or implicit detection of facial expression of pain. ⋯ Specifically, the results showed that participants, regardless of their gender, were slower and less accurate in recognizing pain expressions (but not other expressions) on female faces. Furthermore, androgynous faces displaying pained expressions were more likely to be categorized as male than female. Several potential explanations are discussed.
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In present study, in vivo electrophysiological techniques were applied to examine the effects of anterior cingulate cortex (ACC) activation on mechanical and electrical stimuli-evoked responses in rat spinal cord wide-dynamic-range (WDR) neurons. We found that bilateral ACC electrical stimulation (100Hz, 20V, 20s) had different effects on neuronal responses to brush, pressure and pinch stimuli (10s). The brush-evoked neuronal responses at baseline, post 1min and post 5min were 60.8±15.0, 59.2±15.4 and 60.0±19.3 spikes/10s, respectively (n=10, P>0.05 vs. baseline). ⋯ The total numbers of late response (LR) and after-discharge (AD), but not early response (ER), significantly decreased. Collectively, the present study demonstrated that short-term ACC activation could generate long-term inhibitory effects on the responses of WDR neurons to noxious mechanical (pressure and pinch) and electrical stimuli. The results indicated that ACC activation could negatively regulate noxious information ascending from spinal cord with long-term effect, providing potential neuronal substrate for the modulation of ACC activation on nociception.