Differential encoding of factors influencing predicted reward value in monkey rostral anterior cingulate cortex

Background

The value of a predicted reward can be estimated based on the conjunction of both the intrinsic reward value and the length of time to obtain it. The question we addressed is how the two aspects, reward size and proximity to reward, influence the responses of neurons in rostral anterior cingulate cortex (rACC), a brain region thought to play an important role in reward processing.

Methods and Findings

We recorded from single neurons while two monkeys performed a multi-trial reward schedule task. The monkeys performed 1–4 sequential color discrimination trials to obtain a reward of 1–3 liquid drops. There were two task conditions, a valid cue condition, where the number of trials and reward amount were associated with visual cues, and a random cue condition, where the cue was picked from the cue set at random. In the valid cue condition, the neuronal firing is strongly modulated by the predicted reward proximity during the trials. Information about the predicted reward amount is almost absent at those times. In substantial subpopulations, the neuronal responses decreased or increased gradually through schedule progress to the predicted outcome. These two gradually modulating signals could be used to calculate the effect of time on the perception of reward value. In the random cue condition, little information about the reward proximity or reward amount is encoded during the course of the trial before reward delivery, but when the reward is actually delivered the responses reflect both the reward proximity and reward amount.

Conclusions

Our results suggest that the rACC neurons encode information about reward proximity and amount in a manner that is dependent on utility of reward information. The manner in which the information is represented could be used in the moment-to-moment calculation of the effect of time and amount on predicted outcome value.     

School level contextual factors are associated with the weight status of adolescent males and females

Objective: To determine whether school context influences the BMI of adolescent males and females. Methods and Procedures: Our sample was 17,007 adolescents (aged 12–19) from the National Longitudinal Study of Adolescent Health (Add Health). We used gender‐stratified multilevel modeling to examine the contribution of schools to the overall variance in adolescent BMIs, calculated from self‐reported weight and height. We then examined the associations of individual attributes with BMI after controlling for the average BMI of the school and the association of two school‐level variables with BMI. Results: Participants attended schools that were segregated by race/ethnicity and socioeconomic status (SES). In females, when controlling only for individual‐level attributes, individual household income was inversely associated (β = ?0.043, P = 0.01) while Hispanic (β = 0.89, P < 0.001) and black (β = 1.61, P < 0.001) race/ethnicity were positively associated with BMI. In males, Hispanic (β = 0.67, P < 0.001) race/ethnicity was positively associated with BMI; there was no difference in the BMIs of blacks compared with whites (β = 0.24, P = 0.085). After controlling for the school racial/ethnic makeup and the school level median household income, the relationship between individual race/ethnicity and BMI was attenuated in both male and female adolescents. Higher school level median household income was associated with lower individual BMIs in adolescent girls (γ = ?0.37, P < 0.001) and boys (γ = ?0.29, P < 0.001) suggesting a contextual effect of the school. Discussion: Male and female adolescents attending schools with higher median household incomes have on average lower BMIs. Resources available to or cultural norms within schools may constitute critical mechanisms through which schools impact the BMI of their students.     

The annexin 2-S100A10 complex and its association with TRPV6 is regulated by cAMP/PKA/CnA in airway and gut epithelia

The formation of a heterotetrameric complex between annexin 2 (anx 2) and S100A10 plays an important role in regulating the cellular distribution and biochemical properties of anx 2. A major distinction between the anx 2-S100A10 complex and other annexin-S100 complexes is that S100A10 binding to anx 2 occurs independently of calcium. Here we describe a cyclic 3',5'-adenosine monophosphate (cAMP) and cAMP-dependent protein kinase (PKA, EC 2.7.1.37)-dependent mechanism regulating anx 2-S100A10 complex formation and its interaction with the transient receptor potential vanilloid type 6 channel (TRPV6) in airway and gut epithelia. In both 16HBE14o- and Caco-2 cells, forskolin (FSK) stimulated increased anx 2-S100A10 complex formation, which was attenuated by either PKA inhibitors or calcineurin A (CnA) inhibitors. The anx 2-S100A10 complex association with TRPV6 was dependent on FSK-induced CnA-dependent dephosphorylation of anx 2. Analysis of the significance of the cAMP/PKA/CnA pathway on calcium influx showed that both PKA and CnA inhibitors attenuated Ca(45) uptake in Caco-2, but not 16HBE14o-, cells. Thus, the cAMP/PKA/CnA-induced anx 2-S100A10/TRPV6 complex may require additional factors for calcium influx or play a role independent of calcium influx in airway epithelia. In conclusion, our data demonstrates that cAMP/PKA/CnA signalling is important for anx 2-S100A10 complex formation and interaction with target molecules in both absorptive and secretory epithelia.     

Evolutionarily conserved thermal biology across continents: The North American lizard Plestiodon gilberti (Scincidae) compared to Asian Plestiodon

1.

The lizard genus Plestiodon (Scincidae; formerly Eumeces) is widespread in North America and Asia, but the thermal biology of only a few species has been studied.