Rehabilitation of working memory after acquired brain injury and multiple sclerosis: A systematic review.

The objective is to study the effectiveness of working memory (WM) rehabilitation after Acquired brain injury (ABI) and multiple sclerosis (MS). A systematic database search of published studies, following PRISMA recommendations, with assessment of methodological quality and risk of bias, was conducted. The results were analysed according to the rehabilitation method used.

Universal tree structures in directed polymers and models of evolving populations.

By measuring or calculating coalescence times for several models of coalescence or evolution, with and without selection, we show that the ratios of these coalescence times become universal in the large size limit and we identify a few universality classes.

The stochastic edge in adaptive evolution.

In a recent article, Desai and Fisher proposed that the speed of adaptation in an asexual population is determined by the dynamics of the stochastic edge of the population, that is, by the emergence and subsequent establishment of rare mutants that exceed the fitness of all sequences currently present in the population. Desai and Fisher perform an elaborate stochastic calculation of the mean time tau until a new class of mutants has been established and interpret 1/tau as the speed of adaptation. As they note, however, their calculations are valid only for moderate speeds.

The traveling-wave approach to asexual evolution: Muller's ratchet and speed of adaptation.

We use traveling-wave theory to derive expressions for the rate of accumulation of deleterious mutations under Muller's ratchet and the speed of adaptation under positive selection in asexual populations. Traveling-wave theory is a semi-deterministic description of an evolving population, where the bulk of the population is modeled using deterministic equations, but the class of the highest-fitness genotypes, whose evolution over time determines loss or gain of fitness in the population, is given proper stochastic treatment. We derive improved methods to model the highest-fitness class (the stochastic edge) for both Muller's ratchet and adaptive evolution, and calculate analytic correction terms that compensate for inaccuracies which arise when treating discrete fitness classes as a continuum.

Reasoning about physical causality and other's intentions in schizophrenia.

Introduction: Several studies have shown that schizophrenic patients have impaired theory-of-mind skills involving the attribution of false beliefs and intentions to others. Despite the methodological difficulties of false belief protocols, experiments have concluded that the deficit is specific and cannot be explained in terms of a general cognitive impairment. The situation, however, remains unclear as far as the attribution of intentions to others is concerned.

Empathy examined through the neural mechanisms involved in imagining how I feel versus how you feel pain.

Perspective-taking is a stepping stone to human empathy. When empathizing with another individual, one can imagine how the other perceives the situation and feels as a result. To what extent does imagining the other differs from imagining oneself in similar painful situations? In this functional magnetic resonance imaging experiment, participants were shown pictures of people with their hands or feet in painful or non-painful situations and instructed to imagine and rate the level of pain perceived from different perspectives.

Exactly soluble noisy traveling-wave equation appearing in the problem of directed polymers in a random medium.

We calculate exactly the velocity and diffusion constant of a microscopic stochastic model of N evolving particles which can be described by a noisy traveling-wave equation with a noise of order N(-1/2). Our model can be viewed as the infinite range limit of a directed polymer in random medium with N sites in the transverse direction. Despite some peculiarities of the traveling-wave equations in the absence of noise, our exact solution allows us to test the validity of a simple cutoff approximation and to show that, in the weak noise limit, the position of the front can be completely described by the effect of the noise on the first particle.

Fluctuations of the winding number of a directed polymer in a random medium.

For a directed polymer in a random medium lying on an infinite cylinder that is in 1+1 dimensions with finite width and periodic boundary conditions on the transverse direction, the winding number is simply the algebraic number of turns the polymer does around the cylinder. This paper presents exact expressions of the fluctuations of this winding number due to, first, the thermal noise of the system and, second, the different realizations of the disorder in the medium.

Abnormalities of brain function during a nonverbal theory of mind task in schizophrenia.

Theory of mind (ToM), the specific ability to attribute thoughts and feelings to oneself and others is generally impaired in schizophrenia. Previous studies demonstrated a deficit of the attribution of intentions to others among patients having formal thought disorder. During nonverbal tasks, such a function requires both the visual perception of human figures and the understanding of their intentions.