A data-driven approach to neuropsychological features in isolated REM behaviour disorder: A latent class analysis

Recent evidence demonstrated that neuropsychological assessment may be considered a valid marker of neurodegeneration in idiopathic REM sleep behaviour disorder (iRBD). However, little is known about the possible neuropsychological heterogeneity within the iRBD population. This retrospective study aimed to identify and describe different neuropsychological phenotypes in iRBD patients by means of a data-driven approach using latent class analysis. A total of 289 iRBD patients underwent a neuropsychological assessment evaluating cognitive domains: global cognition, language, short- and long-term memory, executive functions and visuospatial abilities. The presence of mild cognitive impairment (MCI) was also assessed. Latent class analysis was carried out to identify iRBD subtypes according to neuropsychological scores. The most parsimonious model identified three latent classes. Groups were labelled as follows: Class 2 “severely impaired” (n = 83/289): mean pathological scores in different tests, a high percentage of MCI multiple-domain and impairment in all neuropsychological domains. Class 1 “moderately impaired” (n = 44/289): mean neuropsychological score within the normal value, a high percentage of MCI (high risk to phenoconversion) and great impairment in the visuospatial domain. Class 3 “slightly impaired” (n = 162/289): no deficit worthy of attention except for short- and long-term memory. Our results suggest three different clinical phenotypes within the iRBD population. These findings may be relevant in the future for predicting the clinical trajectories of phenoconversion in iRBD.     

Prejudice as Viciousness: Marie de Gournay and Anton Wilhelm Amo

Marie de Gournay and Anton Wilhelm Amo, though thinking and writing in different social contexts, each offer an account of prejudice which bears a deep philosophical resonance to that of the other. This resonance is striking and mutually illuminating: Gournay and Amo develop a view of prejudice as a kind of epistemic and moral viciousness that damages both the prejudicial person and their socio-epistemic neighbors. Their accounts highlight how agents are rightly held responsible for prejudice, as it is the agents' epistemic negligence and moral failure that allows prejudice to take hold. As such, their view offers a balance between a critical examination of individuals and an acknowledgement of the deep sociality that pervades the epistemic domain.     

Framing COVID-19 as an existential threat predicts prejudice towards Chinese people via anxious arousal

We tested the hypothesis that perceived existential threat stemming from COVID-19 elicits anxious arousal, which can manifest in prejudice toward the perceived source of the threat (Chinese people). Americans (n = 474) were randomly assigned to a condition in which COVID-19 was framed as a high existential threat to the United States or to a condition in which COVID-19 was framed as a low existential threat to the United States. They then completed self-report measures of anxious arousal as well as subtle and blatant prejudice towards Chinese people. As expected, participants in the high threat (vs. low threat) condition reported greater anxious arousal which, in turn, predicted greater subtle and blatant prejudice. The high threat (vs. low threat) condition also indirectly predicted greater subtle and blatant prejudice via greater anxious arousal. Results advance knowledge on the reactions people had to perceiving COVID-19 as an existential threat during the early phase of the pandemic.     

Within-Session Patterns of Pigeons'' General Activity

The study investigates the idea that within-session changes in responding are produced by arousal and satiation. General activity, measured by the displacement of floor panels, was used as an index of these variables. In Experiment 1, pigeons pecked a key on a simple variable-interval schedule and general activity was also recorded. In Experiment 2, pigeons received response-independent reinforcers. In Experiment 3, the pigeons' general activity was reinforced on a variable-interval schedule. Although significant within-session changes in operant key pecking were observed in Experiment 1, within-session changes in general activity were seldom observed in either Experiment 1 or Experiment 2. Significant within-session changes in general activity were observed in Experiment 3, when activity was the operant. The present results can potentially be explained by arousal and satiation. However, the predictive power of this explanation is severely limited. Regardless of whether one accepts arousal and satiation as the theoretical explanation for within-session changes in responding, the present results suggest that aspects of the response–reinforcer relation may determine the within-session pattern of responding.     

Within-Session Changes in Adjunctive and Instrumental Responding

Rats pressed levers for food delivered by several fixed interval schedules. A drinking spout or running wheel was also available during some conditions, but not during others. The rate of lever pressing, drinking and running often changed within experimental sessions. The within-session patterns of lever pressing did not differ when drinking or running was available and when it was not. The correlation between the amount of lever pressing and the amount of drinking or running at a particular time in the session was inconsistently positive or negative. Finding within-session changes in responding for adjunctive behaviors implies that the factors that produce these changes are present for both adjunctive and instrumental behavior. Finding inconsistent correlations between instrumental responding and adjunctive behaviors questions arousal and interference from adjunctive behaviors as explanations for within-session changes in instrumental responding.     

Reinforcer value may change within experimental sessions

Large and systematic changes in response rates often occur within sessions during operant conditioning procedures. In the present experiment, we asked whether the value of the reinforcer that supports responding also changes within sessions. Pigeons pecked a key for mixed grain available throughout the session. Occasionally, wheat was also provided for pecking a second key. The ratio of the rates of responding for mixed grain and wheat, a frequently used measure of relative reinforcer value, changed significantly within sessions when mixed grain was provided at high, but not at low, rates. Habituation to the reinforcer provides the most likely explanation for these changes in reinforcer value. Eventually, habituation may provide a unified explanation for the within-session changes in behavior that occur when many species of subjects respond on a wide variety of tasks.     

Haptic identification of objects and their depictions

Haptic identification of real objects is superior to that of raised two-dimensional (2-D) depictions. Three explanations of real-object superiority were investigated: contribution of material information, contribution of 3-D shape and size, and greater potential for integration across the fingers. In Experiment 1, subjects, while wearing gloves that gently attenuated material information, haptically identified real objects that provided reduced cues to compliance, mass, and part motion. The gloves permitted exploration with free hand movement, a single outstretched finger, or five outstretched fingers. Performance decreased over these three conditions but was superior to identification of pictures of the same objects in all cases, indicating the contribution of 3-D structure and integration across the fingers. Picture performance was also better with five fingers than with one. In Experiment 2, the subjects wore open-fingered gloves, which provided them with material information. Consequently, the effect of type of exploration was substantially reduced but not eliminated. Material compensates somewhat for limited access to object structure but is not the primary basis for haptic object identification.     

Evaluating a treatment without extinction for elopement maintained by access to stereotypy

Elopement is a common and potentially dangerous form of problem behavior. Results of a functional analysis found that the elopement of a child with autism was maintained by access to stereotypy in the form of door play. We implemented functional communication training and contingency-based delays dependent on the absence of elopement and increased the amount of time the participant waited prior to engaging in stereotypy. We also conducted treatment-extension probes, with the participant waiting up to 10 min without elopement.