Physiology & behavior
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Physiology & behavior · May 2014
If it makes you feel bad, don't do it! Egoistic rather than altruistic empathy modulates neural and behavioral responses in moral dilemmas.
According to Greene et al.'s dual-process theory, the differential involvement of emotional processes would explain the different patterns of moral judgments people typically produce when faced with Trolley- and Footbridge-type dilemmas. As a relevant factor, dispositional empathy is known to motivate prosocial behaviors, thus playing a central role in moral judgment and behavior. The present study was aimed at investigating how behavioral and neural correlates of moral decision-making are modulated by the cognitive and affective dimensions of empathy. ⋯ Scores on the Empathic Concern affective subscale of the IRI positively predicted unpleasantness experienced during decision-making for all dilemmas. On the other hand, for Footbridge-type dilemmas only, scores on the Personal Distress affective subscale predicted negatively the mean percentages of utilitarian choices and positively the mean amplitudes of the P260, an ERP component reflecting an immediate emotional reaction during decision-making. It is concluded that "self-oriented" feelings of anxiety and unease, rather than "other-oriented" feelings of concern, affect behavioral choices and emotion-related cortical activity in Footbridge-type moral dilemmas.
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Physiology & behavior · May 2014
C-Fos activation in the periaqueductal gray following acute morphine-3β-D-glucuronide or morphine administration.
Morphine-3β-D-glucuronide (M3G), a primary morphine metabolite, evokes hyperalgesia in mice and rats and putatively mediates hyperalgesia associated with morphine (MOR) administration. However, M3G does not act via opioid receptors and its locus of activity in the CNS is unknown. Here we assessed the density of neurons immunoreactive for c-Fos, an immediate early gene regulated by neuronal activity, in the periaqueductal gray (PAG), a midbrain region critical to pain modulation, in male CD-1 mice after MOR and M3G exposure. ⋯ However, NTX pre-injection blocked this increase in MOR but not M3G injected mice. The data demonstrate for the first time a CNS locus for M3G activity. Consistent with previous observations, this M3G activity is not mediated by opioid receptors.
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Physiology & behavior · Apr 2014
Panax quinquefolium involves nitric oxide pathway in olfactory bulbectomy rat model.
Olfactory bulbectomy (OBX) is a well known screening model for depression. Panax quinquefolium (PQ) is known for its therapeutic potential against several psychiatric disorders. Nitric oxide (NO), an intercellular messenger has been suggested to play a crucial role in the pathogenesis of depression. ⋯ Treatment with PQ significantly and dose-dependently restored these behavioral, biochemical and molecular alterations associated with OBX. Further, pretreatment of l-NAME with subeffective dose of PQ (100mg/kg) significantly potentiated its protective effects; however l-arginine pretreatment reversed the beneficial effects. The present study suggests that protective effect of P. quinquefolium might involve nitric oxide modulatory pathway against olfactory bulbectomy-induced depression in rats.
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Physiology & behavior · Apr 2014
Individual differences in the forced swimming test and neurochemical kinetics in the rat brain.
Individual differences in the forced swimming test (FST) could be associated with differential temporal dynamics of gene expression and neurotransmitter activity. We tested juvenile male rats in the FST and classified the animals into those with low and high immobility according to the amount of immobility time recorded in FST. These groups and a control group which did not undergo the FST were sacrificed either 1, 6 or 24 h after the test. ⋯ Regarding neurotransmitters, only accumbal dopamine turnover and hippocampal glutamate content showed an effect of individual differences (i.e. animals with low and high immobility), whereas nearly all parameters showed significant differences across time points. Correlational analyses suggest that immobility in the FST, probably reflecting despair, is related to prefrontal cortical BDNF and to the kinetics observed in several other neurochemical parameters. Taken together, our results suggest that individual differences observed in depression-like behavior can be associated not only with changes in the concentrations of key neurochemical factors but also with differential time courses of such factors.
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Physiology & behavior · Apr 2014
Role of TNF-α/TNFR1 in intense acute swimming-induced delayed onset muscle soreness in mice.
The injection of cytokines such as TNF-α induces muscle pain. Herein, it was addressed the role of endogenous TNF-α/TNFR1 signaling in intense acute swimming-induced muscle mechanical hyperalgesia in mice. Mice were exposed to water during 30 s (sham) or to a single session of 30-120 min of swimming. ⋯ Exercise induced an increase of myeloperoxidase activity and decrease in reduced glutathione levels in an etanercept-sensitive and TNFR1-dependent manners in the soleus muscle, but not in the gastrocnemius muscle. Concluding, TNF-α/TNFR1 signaling mediates intense acute swimming-induced DOMS by an initial role in the soleus muscle followed by spinal cord, inducing muscle inflammatory hyperalgesia and oxidative stress. The knowledge of these mechanisms might contribute to improve the training of athletes, individuals with physical impairment and intense training such as military settings.