Reconsolidation after remembering an odor-reward association requires NMDA receptors

A rapidly learned odor discrimination task based on spontaneous foraging behavior of the rat was used to evaluate the role of N-methyl-D-aspartate (NMDA) receptors (NMDARs) in ongoing memory consolidation. Rats were trained in a single session to discriminate among three odors, one of which was associated with palatable food reward. Previous experiments showed that the NMDAR antagonist DL-APV induced amnesia for this task when injected immediately after training. In the present study, memory was reactivated 24 h after training by exposure to the rewarded odor within the experimental context after which rats received an intracerebroventricular injection of APV. Combined reactivation-drug treatment induced profound amnesia when tested 48 h later. Animals receiving drug alone, in absence of reactivation, showed perfect retention. It is concluded that NMDARs support a consolidation process taking place after memory reactivation.     

Expectations,gains, and losses in the anterior cingulate cortex

The anterior cingulate cortex (ACC) participates in evaluating actions and outcomes. Little is known on how action-reward values are processed in ACC and if the context in which actions are performed influences this processing. In the present article, we report ACC unit activity of monkeys performing two tasks. The first task tested whether the encoding of reward values is context dependent—that is, dependent on the size of the other rewards that are available in the current block of trials. The second task tested whether unexpected events signaling a change in reward are represented. We show that the context created by a block design (i.e., the context of possible alternative rewards) influences the encoding of reward values, even if no decision or choice is required. ACC activity encodes the relative and not absolute expected reward values. Moreover, cingulate activity signals and evaluates when reward expectations are violated by unexpected stimuli, indicating reward gains or losses.     

Shared understanding and idiosyncratic expression in early vocabularies

To what extent do toddlers have shared vocabularies? We examined CDI data collected from 14,607 infants and toddlers in five countries and measured the amount of variability between individual lexicons during development for both comprehension and production. Early lexicons are highly overlapping. However, beyond 100 words, toddlers share more words with other toddlers in comprehension than in production, even when matched for lexicon sizes. This finding points to a structural difference in early comprehension and production: Toddlers are generalists in comprehension but develop a unique, expressive voice. Variability in production decreases after two years of age, suggesting convergence to a common expressive core vocabulary. We discuss potential exogenous and endogenous contributions to the inverted U‐shaped development observed in young children's expressive lexical variability.     

Between proof and truth

We consider two versions of truth as grounded in verification procedures: Dummett??s notion of proof as an effective way to establish the truth of a statement and Hintikka??s GTS notion of truth as given by the existence of a winning strategy for the game associated with a statement. Hintikka has argued that the two notions should be effective and that one should thus restrict one??s attention to recursive winning strategies. In the context of arithmetic, we show that the two notions do not coincide: on the one hand, proofs in PA do not yield recursive winning strategies for the associated game; on the other hand, there is no sound and effective proof procedure that captures recursive GTS truths. We then consider a generalized version of Game Theoretical Semantics by introducing games with backward moves. In this setting, a connection is made between proofs and recursive winning strategies. We then apply this distinction between two kinds of verificationist procedures to a recent debate about how we recognize the truth of G?delian sentences.     

Shoulder muscles recruitment during a power backward giant swing on high bar: a wavelet-EMG-analysis

This study aimed at determining the upper limb muscles coordination during a power backward giant swing (PBGS) and the recruitment pattern of motor units (MU) of co-activated muscles. The wavelet transformation (WT) was applied to the surface electromyographic (EMG) signal of eight shoulder muscles. Total gymnast's body energy and wavelet synergies extracted from the WT-EMG by using a non-negative matrix factorization were analyzed as a function of the body position angle of the gymnast. A cross-correlation analysis of the EMG patterns allowed determining two main groups of co-activated muscles. Two wavelet synergies representing the main spectral features (82% of the variance accounted for) discriminated the recruitment of MU. Although no task-group of MU was found among the muscles, it appeared that a higher proportion of fast MU was recruited within the muscles of the first group during the upper part of the PBGS. The last increase of total body energy before bar release was induced by the recruitment of the muscles of the second group but did not necessitate the recruitment of a higher proportion of fast MU. Such muscle coordination agreed with previous simulations of elements on high bar as well as the findings related to the recruitment of MU.     

Self-determination: a buffer against suicide ideation

Self-determination was examined as a protective factor against the detrimental impact of negative life events on suicide ideation in adolescents. It is postulated that for highly self-determined adolescents, negative life events have a weaker impact on both hopelessness and suicide ideation than for non-self-determined adolescents. In turn, hopelessness is hypothesized to generate less suicide ideation for highly self-determined individuals. Results from multigroup analyses confirm that both the direct and indirect links between negative life events and suicide ideation were significantly weaker among participants high in self-determination. The protective role of self-determination against negative life events is discussed.     

Thoughts on how to regulate behaviours: an overview of the current debate

ABSTRACT

The article intends to present the debate on behaviour modification in the regulation studies literature, at a time of renewed interest among regulators for new ideas and strategies. As the financial crisis has led to the most public critique yet of the rational choice view of individuals that has informed regulation in the last few decades, other ideas that value realism more than simplicity and parsimony deserve some attention. Some of these – proposed by behavioural economics – have already raised considerable interest from regulators, especially in the UK and the USA, and have begun to impact various types of regulation. This article puts these various elements in perspective and as such provides tools to appraise and engage with past and future attempts to regulate social groups in health care and elsewhere.     

Defining the boundary of childhood amnesia

When adults are asked to recall their earliest autobiographical memories most can recall nothing about their infancy and early childhood, a phenomenon commonly referred to as childhood amnesia. There is general consensus regarding the existence of childhood amnesia, but there remains considerable debate over its boundary. Most researchers have argued that the boundary of childhood amnesia occurs between the ages of 3 and 4 years, but in 1993 Usher and Neisser published a highly influential paper, which has subsequently been used to argue that the boundary may be as low as 2 years. In the present experiment we examined how changes in scoring criteria influence our estimates of the age of adults’ earliest memories. We conclude that some coding criteria are more valid than others and that the best estimates of childhood amnesia will include measures of free recall in addition to the specific questions that have dominated prior research in this area.