Classical conditioning and pain: Conditioned analgesia and hyperalgesia

This article reviews situations in which stimuli produce an increase or a decrease in nociceptive responses through basic associative processes and provides an associative account of such changes. Specifically, the literature suggests that cues associated with stress can produce conditioned analgesia or conditioned hyperalgesia, depending on the properties of the conditioned stimulus (e.g., contextual cues and audiovisual cues vs. gustatory and olfactory cues, respectively) and the proprieties of the unconditioned stimulus (e.g., appetitive, aversive, or analgesic, respectively). When such cues are associated with reducers of exogenous pain (e.g., opiates), they typically increase sensitivity to pain. Overall, the evidence concerning conditioned stress-induced analgesia, conditioned hyperalagesia, conditioned tolerance to morphine, and conditioned reduction of morphine analgesia suggests that selective associations between stimuli underlie changes in pain sensitivity.     

Living on the edge: strategic and instructed slowing in the stop signal task

The stop signal task is widely adopted to assess motor inhibition performance in both clinical and non-clinical populations. Several recent studies explored the influence of strategic approaches to the task. In particular, response slowing seems to be a strategic approach commonly adopted to perform the task. In the present study, we compared a standard version with a strategic version of the task, in which participants were explicitly instructed to slow down responses. Results showed that the instructed slowing did not affect the main inhibition measure, thus confirming the robustness of the stop signal index. On the other hand, it apparently changed the nature of the task, as shown by the lack of correlation between the standard and the strategic versions. In addition, we found a specific influence of individual characteristics on slowing strategies. In the standard version, adherence to task instructions was positively correlated with compliant traits of personality. Despite instructions to maximize response speed, non-compliant participants preferred to adopt a slowing strategy in the standard version of the task, up to a speed level similar to the strategic version, where slowing was required by task instructions. Understanding the role of individual approach to the task seems to be crucial to properly identify how participants cope with task instructions.     

Lack of color integration in visual short-term memory binding

Bicolored objects are retained in visual short-term memory (VSTM) less efficiently than unicolored objects. This is unlike shape–color combinations, whose retention in VSTM does not differ from that observed for shapes only. It is debated whether this is due to a lack of color integration and whether this may reflect the function of separate memory mechanisms. Participants judged whether the colors of bicolored objects (each with an external and an internalcolor) were the same or different across two consecutive screens. Colors had to be remembered either individually or in combination. In Experiment 1, external colors in the combined colors condition were remembered better than the internal colors, and performance for both was worse than that in the individual colors condition. The lack of color integration observed in Experiment 1 was further supported by a reduced capacity of VSTM to retain color combinations, relative to individual colors (Experiment 2). An additional account was found in Experiment 3, which showed spared color–color binding in the presence of impaired shape–color binding in a brain-damaged patient, thus suggesting that these two memory mechanisms are different.     

False reports from patients with frontotemporal dementia: delusions or confabulations?

Patients with behavioral variant frontotemporal dementia (bvFTD) can make false statements consistent with delusions or confabulations. It is unclear whether bvFTD is primarily associated with either delusions or with confabulations and whether they can be explained by the pathophysiology of this disease. In order to clarify this, we retrospectively surveyed the records of 48 patients with bvFTD for the presence of any false reports and identified four patients. Their false reports included continued interaction with a favorite but dead relation, fictitious marriages with movie stars, and two who claimed that their partner was having an affair. When confronted with the falsity of their statements, the patients conveyed a lack of certainty regarding their external or internal source but persisted in the constancy of their reports. On functional neuroimaging, the patients had predominant frontal involvement. This report found that patients with bvFTD can have both fantastic, wish fulfilling confabulations and typical content-specific delusions. We propose that both phenomena result from known disturbances of ventromedial prefrontal cortex in bvFTD, including deficits in source monitoring and in activating an automatic "doubt tag" for false reports.     

Conceptual Change,Crucial Experiments and Auxiliary Hypotheses. A Theoretical Contribution

Theories about conceptual change have been generally related to historical and philosophical analysis of science. Yet, there is still much debate on how ideas coming from the history of science and their implications can be applied in this field. Our study intends to investigate the complex structure of conceptual change, by making use of some particularly representative features of the History and Philosophy of science, while considering the structure of so-called crucial experiments and the specific role of implicit hypotheses. Due to their historical importance and logical reasoning aspects, examining these issues may contribute to understand how conceptual change may take place.