Hippocampus-dependent emergence of spatial sequence coding in retrosplenial cortex.

Retrosplenial cortex (RSC) is involved in visuospatial integration and spatial learning, and RSC neurons exhibit discrete, place cell-like sequential activity that resembles the population code of space in hippocampus. To investigate the origins and population dynamics of this activity, we combined longitudinal cellular calcium imaging of dysgranular RSC neurons in mice with excitotoxic hippocampal lesions. We tracked the emergence and stability of RSC spatial activity over consecutive imaging sessions. Overall, spatial activity in RSC was experience-dependent, emerging gradually over time, but, as seen in the hippocampus, the spatial code changed dynamically across days. Bilateral but not unilateral hippocampal lesions impeded the development of spatial activity in RSC. Thus, the emergence of spatial activity in RSC, a major recipient of hippocampal information, depends critically on an intact hippocampus; the indirect connections between the dysgranular RSC and the hippocampus further indicate that hippocampus may exert such influences polysynaptically within neocortex

INDICATEURS FINANCIERS ET INDICATEURS NON FINANCIERS. IMPORTANCE DES INDICATEURS FINANCIERS, ET ORDRE DE PRESENTATION DES INDICATEURS : EFFETS SUR L'EVALUATION DE LA PERFORMANCE DES MANAGERS

International audienceDebate on the weight of financial vs. non financial indicators in performance measurement process is still going on. The purpose of this research is to examine, experimentally, factors that influence whether corporate managers exhibit bias toward financial versus nonfinancial corporate performance measures. First, we manipulated presentation order of financial and nonfinancial measures to test whether cognitive processing limits result in decision makers placing more weight on the first few items presented. Second, we manipulated the strength of the financial performance measures (the perceived relative importance based on rankings by an independent sample) to examine whether prior mixed results of financial measures bias among corporate managers can be explained by differences in the relative strength or importance of the particular set of financial and nonfinancial measures.Le débat sur l'importance des indicateurs non financiers et financiers dans le processus d'évaluation des performances est loin d'être clos. L'objectif de notre recherche est d'examiner, de façon expérimentale, les facteurs qui influencent le choix des évaluateurs en faveur des indicateurs financiers ou non financiers dans l'évaluation des performances d'une entreprise. Nous avons ainsi d'une part manipulé l'ordre de présentation des indicateurs financiers et non financiers dans le but de tester si les limitations cognitives conduisaient les évaluateurs à considérer seulement les premiers indicateurs qui leur étaient présentés. D'autre part, nous avons manipulé l'importance relative perçue des indicateurs financiers afin d'examiner si le biais en faveur des indicateurs financiers, souvent démontré, pouvait être expliqué par la nature même de ces indicateurs. L'importance relative perçue des indicateurs financiers se fondait sur les résultats d'une autre étude que nous avons conduite sur un échantillon indépendant

INDICATEURS FINANCIERS ET INDICATEURS NON FINANCIERS. IMPORTANCE DES INDICATEURS FINANCIERS, ET ORDRE DE PRESENTATION DES INDICATEURS : EFFETS SUR L'EVALUATION DE LA PERFORMANCE DES MANAGERS

Le débat sur l'importance des indicateurs non financiers et financiers dans le processus d'évaluation des performances est loin d'être clos. L'objectif de notre recherche est d'examiner, de façon expérimentale, les facteurs qui influencent le choix des évaluateurs en faveur des indicateurs financiers ou non financiers dans l'évaluation des performances d'une entreprise. Nous avons ainsi d'une part manipulé l'ordre de présentation des indicateurs financiers et non financiers dans le but de tester si les limitations cognitives conduisaient les évaluateurs à considérer seulement les premiers indicateurs qui leur étaient présentés. D'autre part, nous avons manipulé l'importance relative perçue des indicateurs financiers afin d'examiner si le biais en faveur des indicateurs financiers, souvent démontré, pouvait être expliqué par la nature même de ces indicateurs. L'importance relative perçue des indicateurs financiers se fondait sur les résultats d'une autre étude que nous avons conduite sur un échantillon indépendant.Evaluation des performances; Indicateurs financiers vs.Non financiers; Biais cognitif; Ordre de présentation des informations

Involvement of fast-spiking cells in ictal sequences during spontaneous seizures in rats with chronic temporal lobe epilepsy

Epileptic seizures represent altered neuronal network dynamics, but the temporal evolution and cellular substrates of the neuronal activity patterns associated with spontaneous seizures are not fully understood. We used simultaneous recordings from multiple neurons in the hippocampus and neocortex of rats with chronic temporal lobe epilepsy to demonstrate that subsets of cells discharge in a highly stereotypical sequential pattern during ictal events, and that these stereotypical patterns were reproducible across consecutive seizures. In contrast to the canonical view that principal cell discharges dominate ictal events, the ictal sequences were predominantly composed of fast-spiking, putative inhibitory neurons, which displayed unusually strong coupling to local field potential even before seizures. The temporal evolution of activity was characterized by unique dynamics where the most correlated neuronal pairs before seizure onset displayed the largest increases in correlation strength during the seizures. These results demonstrate the selective involvement of fast spiking interneurons in structured temporal sequences during spontaneous ictal events in hippocampal and neocortical circuits in experimental models of chronic temporal lobe epilepsy

Third order dielectric susceptibility in a model quantum paraelectric

In the context of perovskite quantum paraelectrics, we study the effects of a quadrupolar interaction $J_q$, in addition to the standard dipolar one $J_d$. We concentrate here on the nonlinear dielectric response $\chi_{P}^{(3)}$, as the main response function sensitive to quadrupolar (in our case antiquadrupolar) interactions. We employ a 3D quantum four-state lattice model and mean-field theory. The results show that inclusion of quadrupolar coupling of moderate strength ($J_q \sim {{1}\over{4}} J_d$) is clearly accompanied by a double change of sign of $\chi_{P}^{(3)}$ from negative to positive, near the quantum temperature $T_Q$ where the quantum paraelectric behaviour sets in. We fit our $\chi_{P}^{(3)}$ to recent experimental data for SrTiO$_3$, where the sign change is identified close to $T_Q \sim 37 K$.Comment: 22 page

Private Sector Union Density and the Wage Premium: Past, Present, and Future

The rise and decline of private sector unionization were among the more important features of the U.S. labor market during the twentieth century. Following a dramatic spurt in unionization after passage of the depression-era National Labor Relations Act (NLRA) of 1935, union density peaked in the mid-1950s, and then began a continuous decline. At the end of the century, the percentage of private wage and salary workers who were union members was less than 10 percent, not greatly different from union density prior to the NLRA

Caloric Restriction Suppresses Microglial Activation and Prevents Neuroapoptosis Following Cortical Injury in Rats

Traumatic brain injury (TBI) is a widespread cause of death and a major source of adult disability. Subsequent pathological events occurring in the brain after TBI, referred to as secondary injury, continue to damage surrounding tissue resulting in substantial neuronal loss. One of the hallmarks of the secondary injury process is microglial activation resulting in increased cytokine production. Notwithstanding that recent studies demonstrated that caloric restriction (CR) lasting several months prior to an acute TBI exhibits neuroprotective properties, understanding how exactly CR influences secondary injury is still unclear. The goal of the present study was to examine whether CR (50% of daily food intake for 3 months) alleviates the effects of secondary injury on neuronal loss following cortical stab injury (CSI). To this end, we examined the effects of CR on the microglial activation, tumor necrosis factor-α (TNF-α) and caspase-3 expression in the ipsilateral (injured) cortex of the adult rats during the recovery period (from 2 to 28 days) after injury. Our results demonstrate that CR prior to CSI suppresses microglial activation, induction of TNF-α and caspase-3, as well as neurodegeneration following injury. These results indicate that CR strongly attenuates the effects of secondary injury, thus suggesting that CR may increase the successful outcome following TBI

Biofilm Derived Oxylipin Mediated Autoimmune Response in Breast Implant Subjects

Over 10 million women worldwide have breast implants for breast cancer/prophylactic reconstruction or cosmetic augmentation. In recent years, a number of patients have described a constellation of symptoms that are believed to be related to their breast implants. This constellation of symptoms has been named Breast Implant Illness (BII). The symptoms described include chronic fatigue, joint pain, muscle pain and a host of other manifestations often associated with autoimmune illnesses. In this work, we report that bacterial biofilm is associated with BII. We postulate that the pathogenesis of BII is mediated via a host-pathogen interaction whereby the biofilm bacteria Staphylococcus epidermidis interacts with breast lipids to form the oxylipin 10-HOME. The oxylipin 10-HOME was found to activate CD4+ T cells to Th1 subtype. An increased abundance of CD4+Th1 was observed in the breast tissue of BII subjects. The identification of a mechanism of immune activation associated with BII via a biofilm enabled pathway provides insight into the pathogenesis for implant-associated autoimmune symptoms