Human insula activation reflects risk prediction errors as well as risk

Understanding how organisms deal with probabilistic stimulus-reward associations has been advanced by a convergence between reinforcement learning models and primate physiology, which demonstrated that the brain encodes a reward prediction error signal. However, organisms must also predict the level of risk associated with reward forecasts, monitor the errors in those risk predictions, and update these in light of new information. Risk prediction serves a dual purpose: (1) to guide choice in risk-sensitive organisms and (2) to modulate learning of uncertain rewards. To date, it is not known whether or how the brain accomplishes risk prediction. Using functional imaging during a simple gambling task in which we constantly changed risk, we show that an early-onset activation in the human insula correlates significantly with risk prediction error and that its time course is consistent with a role in rapid updating. Additionally, we show that activation previously associated with general uncertainty emerges with a delay consistent with a role in risk prediction. The activations correlating with risk prediction and risk prediction errors are the analogy for risk of activations correlating with reward prediction and reward prediction errors for reward expectation. As such, our findings indicate that our understanding of the neural basis of reward anticipation under uncertainty needs to be expanded to include risk prediction

Neural Differentiation of Expected Reward and Risk in Human Subcortical Structures

In decision-making under uncertainty, economic studies emphasize the importance of risk in addition to expected reward. Studies in neuroscience focus on expected reward and learning rather than risk. We combined functional imaging with a simple gambling task to vary expected reward and risk simultaneously and in an uncorrelated manner. Drawing on financial decision theory, we modeled expected reward as mathematical expectation of reward, and risk as reward variance. Activations in dopaminoceptive structures correlated with both mathematical parameters. These activations differentiated spatially and temporally. Temporally, the activation related to expected reward was immediate, while the activation related to risk was delayed. Analyses confirmed that our paradigm minimized confounds from learning, motivation, and salience. These results suggest that the primary task of the dopaminergic system is to convey signals of upcoming stochastic rewards, such as expected reward and risk, beyond its role in learning, motivation, and salience. © 2006 Elsevier Inc. All rights reserved

The Careers of Urban Teachers: A Synthesis of Findings from UCLA's Longitudinal Study of Urban Educators

This paper synthesizes the findings of a six-year longitudinal retention study of more than one thousand urban educators in their first through tenth year of the profession. The educators studied were graduates of UCLA's Center X Teacher Education Program and the results of the study may be generalized to the population of well-prepared urban teachers nationwide, with one exception. Although most Center X graduates are female (79%), which is similar to national trends, the group’s ethnic and racial diversity contrasts sharply with national norms (though it reflects California’s increasing diversity). The longitudinal study consisted of a range of quantitative and qualitative studies to answer the following questions: (1) What is the effect of specialized teacher preparation on retention? (2) What is the effect of career advancement on attrition among highly-qualified urban educators? (3) What individual and school characteristics are associated with retention in high-poverty schools? This paper reports that Center X’s specialized approach to teacher education had a positive impact on workplace retention, but not role retention. If they decided to stay in teaching, Center X graduates were much more likely than similar teachers nationwide to stay put in the same school over time. This finding has important implications for the organizational stability and potential reform of urban schools. Focusing in on the issue of role retention, the paper reports that the proportion of attrition among Center X graduates due to changing roles within the field of education was 70% after eight years in the profession. Although largely hidden from policy view, the paper discusses how role changing is a form of sanctioned attrition that should be added to the landscape of teacher retention research. Finally, the paper reports findings that stand in stark contrast to a number of studies that have found teachers systematically move away from schools with low levels of achievement and high concentrations of poor children of color. The paper reports how student disadvantage along with the quality of a school’s professional learning community contributes to workplace retention in high poverty urban schools. The concluding section outlines promising policy responses for creating and sustaining urban schools where teachers are professionally respected, challenged, and supported; where they have autonomy and voice; and where they feel they can make a difference in the lives of their students