Reacquisition of heroin and cocaine place preference involves a memory consolidation process sensitive to systemic and intra-ventral tegmental area naloxone

To investigate the effect of naloxone on a putative memory consolidation process underlying reacquisition of heroin and cocaine conditioned place preference, four studies were conducted in male Sprague–Dawley rats using a common procedure involving: place conditioning (0.3 or 1 mg/kg heroin or 20 mg/kg cocaine; ×4 sessions), extinction (vehicle × 4 sessions), and reconditioning (0 or 1 mg/kg heroin or 20 mg/kg cocaine; ×1 session). Systemic naloxone injections (0, 1 and 3 mg/kg) or bilateral intra-ventral tegmental area (VTA) naloxone methiodide infusions (2 nmol in 0.5 μl × side) were administered at different times following reconditioning. Post-reconditioning administration of naloxone dose-dependently blocked, attenuated and had no effect on reacquisition of heroin CPP when administered immediately, 1 h and 6 h after reconditioning, respectively. The highest dose of naloxone also blocked reacquisition of cocaine CPP, and did not produce a conditioned place aversion in heroin-naïve and heroin pre-treated animals. Post-reconditioning infusions in the VTA, but not in adjacent structures, blocked reacquisition of heroin CPP when administered immediately, but not 6 h, after reconditioning. These data suggest that reacquisition of drug-cues associations involves a memory consolidation process sensitive to manipulations of the endogenous opioid system, and indicate that opioid receptors in the VTA may be critically involved in the re-emergence of drug seeking behavior.     

A modified mark test for own-body recognition in pig-tailed macaques (Macaca nemestrina)

Classic mirror self-recognition mark tests involve familiarizing the subject with its mirror image, surreptitiously applying a mark on the subject’s eyebrow, nose, or ear, and measuring self-directed behaviors toward the mark. For many non-human primate species, however, direct gaze at the face constitutes an aggressive and threatening signal. It is therefore possible that monkeys fail the mark test because they do not closely inspect their faces in a mirror and hence they have no expectations about their physical appearance. In the current study, we prevented two pig-tailed macaques (Macaca nemestrina) from seeing their own faces in a mirror, and we adopted a modified version of the classic mark test in which monkeys were marked on the chest, a body region to which they normally have direct visual access but that in the current study was visible only via a mirror. Neither monkey tried to touch the mark on its chest, possibly due to a failure to understand the mirror as a reflective surface. To further the monkeys’ understanding of the mirror image, we trained them to reach for food using the mirror as the only source of information. After both monkeys had learned mirror-mediated reaching, we replicated the mark test. In this latter phase of the study, only one monkey scratched the red dye on the chest once. The results are consistent with other findings suggesting that monkeys are not capable of passing a mark test and imply that face and body recognition rely on the same cognitive abilities.     

Consume More,Work Longer,and Be Unhappy: Possible Social Roots of Economic Crisis?

Applied Research in Quality of Life - According to the Negative Endogenous Growth (NEG) model, economic systems are susceptible to economic crises because they produce wealth from the erosion of...     

Guilt and focusing in decision-making

In this paper we examined the impact of a specific emotion, guilt, on focusing in decision-making. Through the focusing mechanism, when making decisions, individuals tend to restrict their thoughts to what is explicitly represented in the decisional task, disregarding alternatives. In this paper, three experiments are performed to investigate whether an emotional state of guilt can critically guide individuals' focusing, and even prevailing over the focusing mechanism. Guilty emotional state was induced by asking participants to write about a guilty related life event. The emotional state was thus neither generated by nor related to the tasks used in the experiments. Results of the first two studies show that guilt affects focusing in decision-making in the case of only one explicitly specified option (a positive or a negative one). Guilty participants, when presented with a stated option that has predominantly positive characteristics, prefer other, unspecified options over the positive one. Guilty participants faced with a stated option that has predominantly negative features tend to prefer it to other, unspecified, options, instead. Finally, experiment 3 shows that guilty participants presented with two different options (a negative vs. a positive one) having different degrees of explicitness (i.e. they are not equally represented in the decision frame), focus on the negative option, even though the latter was not explicitly represented but only hinted at the end of the text. Overall, these results suggest that guilt emotion state can play a crucial role in either strengthening or reducing the focusing mechanism. Copyright © 2006 John Wiley & Sons, Ltd.     

Brain functional connectivity correlates of coping styles

Coping abilities represent the individual set of mental and behavioral strategies adopted when facing stress or traumatic experiences. Coping styles related to avoidance have been linked to a disposition to develop psychiatric disorders such as PTSD, anxiety, and major depression, whereas problem-oriented coping skills have been positively correlated with well-being and high quality of life. Even though coping styles constitute an important determinant of resilience and can impact many aspects of everyday living, no study has investigated their brain functional connectivity underpinnings in humans. Here we analyzed both psychometric scores of coping and resting-state fMRI data from 102 healthy adult participants. Controlling for personality and problem-solving abilities, we identified significant links between the propensity to adopt different coping styles and the functional connectivity profiles of regions belonging to the default mode (DMN) and anterior salience (AS) networks—namely, the anterior cingulate cortex, left frontopolar cortex, and left angular gyrus. Also, a reduced negative correlation between AS and DMN nodes explained variability in one specific coping style, related to avoiding problems while focusing on the emotional component of the stressor at hand, instead of relying on cognitive resources. These results might be integrated with current neurophysiological models of resilience and individual responses to stress, in order to understand the propensity to develop clinical conditions (e.g., PTSD) and predict the outcomes of psychotherapeutic interventions.     

The role of kinematic mental simulation in creating false memories

Our investigation focuses on memory for scenes depicted in photos. According to the mental model theory, the observation of a static scene depicted in a photo which portrays an actor near to perform an action can trigger a kinematic mental simulation of that action unfolding in time. The deriving prediction is that such a kinematic mental model supports the creation of a false memory of the actor performing an advanced phase of the action. We test this prediction in three experiments in which participants are presented with static scenes of actions, and after three days they perform a recognition task in which they assess recognition of old and novel static scenes depicting actions. The results confirm that false memories occur for actions that represent the unfolding over time of the static action initially observed. Our theoretical framework can accommodate also several previous findings in the literature on false memories.     

Grounding,Quantifiers, and Paradoxes

Journal of Philosophical Logic - The notion of grounding is usually conceived as an objective and explanatory relation. It connects two relata if one—the ground—determines or explains...     

Self-projection in middle childhood: a study on the relationship between theory of mind and episodic future thinking

Cognitive Processing - Growing evidence suggests that theory of mind (ToM) and episodic future thinking (EFT) are closely related at both brain and functional level. This study explored the...