Noninvasive strategies to promote functional recovery after stroke

Stroke is a common and disabling global health-care problem, which is the third most common cause of death and one of the main causes of acquired adult disability in many countries. Rehabilitation interventions are a major component of patient care. In the last few years, brain stimulation, mirror therapy, action observation, or mental practice with motor imagery has emerged as interesting options as add-on interventions to standard physical therapies. The neural bases for poststroke recovery rely on the concept of plasticity, namely, the ability of central nervous system cells to modify their structure and function in response to external stimuli. In this review, we will discuss recent noninvasive strategies employed to enhance functional recovery in stroke patients and we will provide an overview of neural plastic events associated with rehabilitation in preclinical models of stroke

Explicit and implicit timing in older adults: Dissociable associations with age and cognitive decline

This study aimed to test two common explanations for the general finding of age-related changes in the performance of timing tasks within the millisecond-to-second range intervals. The first explanation is that older adults have a real difficulty in temporal processing as compared to younger adults. The second explanation is that older adults perform poorly on timing tasks because of their reduced cognitive control functions. These explanations have been mostly contrasted in explicit timing tasks that overtly require participants to process interval durations. Fewer studies have instead focused on implicit timing tasks, where no explicit instructions to process time are provided. Moreover, the investigation of both explicit and implicit timing in older adults has been restricted so far to healthy older participants. Here, a large sample (N = 85) comprising not only healthy but also pathological older adults completed explicit (time bisection) and implicit (foreperiod) timing tasks within a single session. Participants' age and cognitive decline, measured with the Mini-Mental State Examination (MMSE), were used as continuous variables to explain performance on explicit and implicit timing tasks. Results for the explicit timing task showed a flatter psychometric curve with increasing age or decreasing MMSE scores, pointing to a deficit at the level of cognitive control functions rather than of temporal processing. By contrast, for the implicit timing task, a decrease in the MMSE scores was associated with a reduced foreperiod effect, an index of implicit time processing. Overall, these findings extend previous studies on explicit and implicit timing in healthy aged samples by dissociating between age and cognitive decline (in the normal-to-pathological continuum) in older adults

Explicit and implicit timing in older adults: Dissociable associations with age and cognitive decline

This study aimed to test two common explanations for the general finding of age-related changes in temporal processing. The first one is that older adults have a real difficulty in processing temporal information as compared to younger adults. The second one is that older adults perform poorly on timing tasks because of their reduced cognitive functioning. These explanations have been mostly contrasted in explicit timing tasks, where participants are overtly informed about the temporal nature of the task. Fewer studies have instead focused on age-related differences in implicit timing tasks, where no explicit instructions to process time are provided. Moreover, the comparison of both explicit and implicit timing in older adults has been restricted to healthy aging only. Here, a large sample (N= 85) of healthy and pathological older participants completed explicit (time bisection) and implicit (foreperiod) timing tasks. Participants’ age and general cognitive functioning, measured with the Mini-Mental State Examination (MMSE), were used as continuous variables to explain performance on explicit and implicit timing tasks. Results showed a clear dissociation between the effects of healthy cognitive aging and pathological cognitive decline on processing of explicit and implicit timing. Whereas age and cognitive decline similarly impaired the non-temporal cognitive processes (e.g., memory for and/or attention to durations) involved in explicit temporal judgements, processing of implicit timing survived normal age-related changes. These findings carry important theoretical and practical implications by providing the first experimental evidence that processing of implicit, but not explicit, timing is differentially affected in healthy and pathological aging

CHAMBRE: Integrating multimedia and virtual tools

Current research in interaction aims at defining new types of multimedia and multimodal experience, at enriching everyday objects and environments with the ability to capture user actions and intentions, and at integrating real and virtual sources of information, typically exploiting the visual channel. These forms of interaction usually require dedicated architectures, often relying on different component models, and with rigid types of configuration. We present an approach to the integration of real and virtual world sensors and effectors, and of traditional multimedia environments within a single component-based architecture. Environments in this architecture are defined as networks of plugins, each equipped with computational, presentation and communication capabilities. Examples of integrated environments produceable with this architecture are given. Copyright 2006 ACM

Transcranial Direct Current Stimulation in neurogenetic syndromes: new treatment perspectives for Down syndrome?

This perspective review aims to explore the potential neurobiological mechanisms involved in the application of transcranial Direct Current Stimulation (tDCS) for Down syndrome (DS), the leading cause of genetically-based intellectual disability. The neural mechanisms underlying tDCS interventions in genetic disorders, typically characterized by cognitive deficits, are grounded in the concept of brain plasticity. We initially present the neurobiological and functional effects elicited by tDCS applications in enhancing neuroplasticity and in regulating the excitatory/inhibitory balance, both associated with cognitive improvement in the general population. The review begins with evidence on tDCS applications in five neurogenetic disorders, including Rett, Prader-Willi, Phelan-McDermid, and Neurofibromatosis 1 syndromes, as well as DS. Available evidence supports tDCS as a potential intervention tool and underscores the importance of advancing neurobiological research into the mechanisms of tDCS action in these conditions. We then discuss the potential of tDCS as a promising non-invasive strategy to mitigate deficits in plasticity and promote fine-tuning of the excitatory/inhibitory balance in DS, exploring implications for cognitive treatment perspectives in this population

Effects of Threading Dislocations on AlGaN/GaN High-Electron Mobility Transistors

This brief aims to show the effects of threading edge dislocations on the dc and RF performance of GaN highelectron mobility transistor (HEMT) devices. A state-of-the-art high-frequency and high-power HEMT was investigated with our full-band cellular Monte Carlo (CMC) simulator, which includes the full details of the band structure and the phonon spectra. A complete characterization of the device has been performed using experimental data to calibrate the few adjustable parameters of the simulator. Thermal simulations were also carried out with commercial software in order to operate the corrections needed to model thermal effects. The approach of Weimann based on the results of Read, Bonch-Bruevich and Glasko, and Pödör was then used to model with our CMC code the dislocation effects on the transport properties of HEMT devices. Our simulations indicate that GaN HEMT performance exhibits a fairly large dependence on the density of thread dislocation defects. Furthermore, we show that a threshold concentration exists, above which a complete degradation of the device operation occurs.United States. Air Force Research Laboratory (Contract No. FA8650-08-C-1395)United States. Office of Naval Research (MINE MURI

Autistic-Like Traits and Cerebellar Dysfunction in Purkinje Cell PTEN Knock-Out Mice

Autism spectrum disorders (ASDs) are neurodevelopmental disorders characterized by impaired social interaction, isolated areas of interest, and insistence on sameness. Mutations in Phosphatase and tensin homolog missing on chromosome 10 (PTEN) have been reported in individuals with ASDs. Recent evidence highlights a crucial role of the cerebellum in the etiopathogenesis of ASDs. In the present study we analyzed the specific contribution of cerebellar Purkinje cell (PC) PTEN loss to these disorders. Using the Cre-loxP recombination system, we generated conditional knockout mice in which PTEN inactivation was induced specifically in PCs. We investigated PC morphology and physiology as well as sociability, repetitive behavior, motor learning, and cognitive inflexibility of adult PC PTEN-mutant mice. Loss of PTEN in PCs results in autistic-like traits, including impaired sociability, repetitive behavior and deficits in motor learning. Mutant PCs appear hypertrophic and show structural abnormalities in dendrites and axons, decreased excitability, disrupted parallel fiber and climbing fiber synapses and late-onset cell death. Our results unveil new roles of PTEN in PC function and provide the first evidence of a link between the loss of PTEN in PCs and the genesis of ASD-like traits