Language deficits in pre-symptomatic Huntington's disease: evidence from Hungarian

A limited number of studies have investigated language in Huntington’s disease (HD). These have generally reported abnormalities in rule-governed (grammatical) aspects of language, in both syntax and morphology. Several studies of verbal inflectional morphology in English and French have reported evidence of over-active rule processing, such as over-suffixation errors (e.g., walkeded) and over-regularizations (e.g., digged). Here we extend the investigation to noun inflection in Hungarian, a Finno-Ugric agglutinative language with complex morphology, and to genetically proven pre-symptomatic Huntington’s disease (pre-HD). Although individuals with pre-HD have no clinical, motor or cognitive symptoms, the underlying pathology may already have begun, and thus sensitive behavioral measures might reveal already-present impairments. Indeed, in a Hungarian morphology production task, pre-HD patients made both over-suffixation and over-regularization errors. The findings suggest the generality of over-active rule processing in both HD and pre-HD, across languages from different families with different morphological systems, and for both verbal and noun inflection. Because the neuropathology in pre-HD appears to be largely restricted to the caudate nucleus and related structures, the findings further implicate these structures in language, and in rule-processing in particular. Finally, the need for effective treatments in HD, which will likely depend in part on the ability to sensitively measure early changes in the disease, suggests the possibility that inflectional morphology, and perhaps other language measures, may provide useful diagnostic, tracking, and therapeutic tools for assessing and treating early degeneration in pre-HD and HD.     

Error reactivity in self-paced performance: Highly-accurate individuals exhibit largest post-error slowing

Reaction time is typically increased following an erroneous response. This post-error slowing is traditionally explained by a strategic adjustment of response threshold towards more conservative behaviour. A recently proposed orienting account provides an alternative explanation for post-error slowing. According to this account, committing an error evokes an orienting response (OR), which inhibits information processing in the subsequent trial, resulting in slow and inaccurate performance. We tested a straightforward prediction of the orienting account in the context of self-paced performance, adopting an individual-differences approach: Post-error slowing should be larger the less frequent an error is. To this end, participants were classified into three groups differing in overall performance accuracy. Larger post-error slowing and stronger post-error accuracy decrease were observed for the high-accuracy group than for the two other groups. Practice pronounced the post-error accuracy decline, especially for the high-accuracy group. The results are consistent with the orienting account of post-error slowing but are problematic for accounts based on strategic evaluation mechanisms.     

Stress or no stress: mineralocorticoid receptors in the forebrain regulate behavioral adaptation

Corticosteroid effects on cognitive abilities during behavioral adaptation to stress are mediated by two types of receptors. While the glucocorticoid receptor (GR) is mainly involved in the consolidation of memory, the mineralocorticoid receptor (MR) mediates appraisal and initial responses to novelty. Recent findings in humans and mice suggest that under stress, the MR might be involved in the use of different learning strategies. Here, we used male mice lacking the MR in the forebrain (MR(CaMKCre)), which were subjected to 5-10 min acute restraint stress, followed 30 min later by training trials on the circular hole board. Mice had to locate an exit hole using extra- and intra-maze cues. We assessed performance and the use of spatial and stimulus-response strategies. Non-stressed MR(CaMKCre) mice showed delayed learning as compared to control littermates. Prior stress impaired performance in controls, but did not further deteriorate learning in MR(CaMKCre) mice. When stressed, 20-30% of both MR(CaMKCre) and control mice switched from a spatial to a stimulus-response strategy, which rescued performance in MR(CaMKCre) mice. Furthermore, MR(CaMKCre) mice showed increased GR mRNA expression in all CA areas of the hippocampus and an altered basal and stress-induced corticosterone secretion, which supports their role in the modulation of neuroendocrine activity. In conclusion, our data provide evidence for the critical role of MR in the fast formation of spatial memory. In the absence of forebrain MR spatial learning performance was under basal circumstances impaired, while after stress further deterioration of performance was rescued by switching behavior increasingly to a stimulus-response strategy.     

Naïve Diversification in the Swedish Premium Pension Scheme: Experimental Evidence

In the Swedish Premium Pension Scheme (PPS) all citizens in paid employment allocate part of their public pension savings to mutual funds. In so doing they tend to distribute their choices maximally across different stock fund categories. It is hypothesised that this reflects the naïve application of a variety‐inducing diversification heuristic. The results of two experiments simulating choices of fund categories in the PPS support this hypothesis by showing that participating undergraduates chose stock funds investing in overlapping and non‐overlapping markets or industries in a way demonstrating failure to take into account covariation among fund returns. Administrators of the PPS and similar defined‐contribution pension plans should provide participants with comprehensive advice on how to diversify their investment. Dans le régime de retraite suédois (PPS), tous les citoyens ayant un emploi salarié allouent une part de l'épargne de leur retraite publique à des fonds d'investissements. Ce faisant, ils tendent majoritairement à répartir leurs choix dans différentes catégories de fonds. On a fait l'hypothèse que cela reflète l'application naïve d'une heuristique de la diversification. Les résultats de deux expérimentations simulant des choix entre différentes catégories de fonds pour le PPS confirment cette hypothèse : les sujets (étudiants) ont choisi des fonds en actions et devaient investir sur des marchés ou dans des branches industrielles relevant ou non du même secteur économique et cela d'une façon qui mettait en évidence leur incapacitéà prendre en considération le fait que le retour sur investissement de différents fonds pouvait être lié. Les administrateurs du PPS et de plans de pensions avec versements programmés devraient fournir aux participants des conseils avisés sur la façon de diversifier leur investissement.     

Quantity discrimination by kittens of the domestic cat (Felis silvestris catus)

Animal Cognition - Quantitative abilities are well described in many species and in diverse life situations, including in the adult domestic cat. However, such abilities have been much less studied...     

The Path from Identity Commitments to Adjustment: Motivational Underpinnings and Mediating Mechanisms

The present study focused on motivational underpinnings of identity commitments and mediating mechanisms underlying their effects on well‐being and distress in a sample of college freshmen (N = 399). Using a path model in a structural equation modeling approach, the authors found that causality orientations appeared to serve as motivational antecedents of identity commitments. Identity integration mediated the pathway from identity commitments to adjustment (i.e., well‐being and absence of distress). Suggestions for future research and implications for counseling are provided.