It's all about timing : an electrophysiological examination of feedback-based learning with immediate and delayed feedback

Feedback regarding an individual's action can occur immediately or with a temporal delay. Processing of feedback that varies in its delivery time is proposed to engage different brain mechanisms. fMRI data implicate the striatum in the processing of immediate feedback, and the medial temporal lobe (MTL) in the processing of delayed feedback. The present study offers an electrophysiological examination of feedback processing in the context of timing, by studying the effects of feedback timing on the feedback-related negativity (FRN), a product of the midbrain dopamine system, and elucidating whether the N170 ERP component could capture MTL activation associated with the processing of delayed feedback. Participants completed a word-object paired association learning task; they received feedback 500 ms (immediate feedback condition) following a button press during the learning of two sets of 14 items, and at a delay of 6500 ms (delayed feedback condition) during the learning of the other two sets. The results indicated that while learning outcomes did not differ under the two timing conditions, Event Related Potential (ERPs) pointed to differential activation of the examined ERP components. FRN amplitude was found to be larger following the immediate feedback condition when compared with the delayed feedback condition, and sensitive to valence and learning only under the immediate feedback condition. Additionally, the amplitude of the N170 was found larger following the delayed feedback condition when compared with the immediate feedback condition. Taken together, the findings of the present study support the contention that the processing of delayed feedback involves a shift away from midbrain dopamine activation to the recruitment of the MTL

The eCommentary Machine Project

The eCommentary Machine web application ("eComma") enables groups of students, scholars, or general readers to build collaborative commentaries on a text and to search, display, and share those commentaries online

Rightward-biased hemodynamic response of the parahippocampal system during virtual navigation

Phase reset of parahippocampal electrophysiological oscillations in the theta frequency range is said to contribute to item encoding and retrieval during spatial navigation. Although well-studied in non-human animals, this mechanism is poorly understood in humans. Previously we found that feedback stimuli presented in a virtual maze environment elicited a burst of theta power over right-posterior areas of the human scalp, and that the power and phase angle of these oscillations were greater following right turns compared to left turns in the maze. Here we investigated the source of this effect with functional magnetic resonance imaging. Consistent with our predictions, we found that 1) feedback encountered in the maze task activated right parahippocampal cortex (PHC), 2) right PHC was more activated by rewards following right turns compared to left turns in the maze, and 3) the rightward-biased activation was more pronounced in individuals who displayed good spatial abilities. These findings support our previous electrophysiological findings and highlight, in humans, a role for PHC theta oscillations in encoding salient information for the purpose of spatial navigation

The role of leadership in emergent, self-organization

As complex systems, organizations exist far from equilibrium where the ongoing interaction of system components leads to emergent and self-organizing behavior. What, then, is the role of leadership in systems where change often emerges in unexpected ways? In this paper, we build on the work of Marion and Uhl-Bien who suggest that in complex systems leaders enable rather than control the future. While traditional views of leadership focus on the leader’s responsibility for determining and directing the future through heavy reliance on control mechanisms, we offer empirical support for a different view of leadership based on a complexity perspective of organizations. Our findings show that as enablers, leaders disrupt existing patterns of behavior, encourage novelty, and make sense of emerging events for others. The results of our qualitative study include a set of research propositions as well as a discussion of the implications for managers and researchers

Radical Change Accidentally: The Emergence and Amplification of Small Change

A decision to offer breakfast to homeless people led to radical change in a church and its environment. Existing theories of change do not fully explain observations from our qualitative study; however, complexity theory constructs suggest how and why such change emerged. We offer four key findings. First, the radical change was unintended, emergent, and slow. Second, destabilizing conditions helped small changes to emerge and become radical. Third, subsequent actions amplified an initial small change and, though not intended to do so, promoted radical change. Finally, the dynamic interaction of amplifying actions, contextual conditions, and small changes led to continuous radical change

Radical Change Accidentally: The Emergence and Amplification of Small Change

A decision to offer breakfast to homeless people led to radical change in a church and its environment. Existing theories of change do not fully explain observations from our qualitative study; however, complexity theory constructs suggest how and why such change emerged. We offer four key findings. First, the radical change was unintended, emergent, and slow. Second, destabilizing conditions helped small changes to emerge and become radical. Third, subsequent actions amplified an initial small change and, though not intended to do so, promoted radical change. Finally, the dynamic interaction of amplifying actions, contextual conditions, and small changes led to continuous radical change

Effects of delaying binge drinking on adolescent brain development : a longitudinal neuroimaging study

Background: Onset of alcohol use by 14 relative to 21 years of age strongly predicts elevated risk for severe alcohol use problems, with 27% versus 4% of individuals exhibiting alcohol dependence within 10 years of onset. What remains unclear is whether this early alcohol use (i) is a marker for later problems, reflected as a pre-existing developmental predisposition, (ii) causes global neural atrophy or (iii) specifically disturbs neuro-maturational processes implicated in addiction, such as executive functions or reward processing. Since our group has demonstrated that a novel intervention program targeting personality traits associated with adolescent alcohol use can prevent the uptake of drinking and binge drinking by 40 to 60%, a crucial question is whether prevention of early onset alcohol misuse will protect adolescent neurodevelopment and which domains of neurodevelopment can be protected. Methods: A subsample of 120 youth at high risk for substance misuse and 30 low-risk youth will be recruited from the Co-Venture trial (Montreal, Canada) to take part in this 5-year follow-up neuroimaging study. The Co-Venture trial is a community-based cluster-randomised trial evaluating the effectiveness of school-based personality-targeted interventions on substance use and cognitive outcomes involving approximately 3800 Grade 7 youths. Half of the 120 high-risk participants will have received the preventative intervention program. Cognitive tasks and structural and functional neuroimaging scans will be conducted at baseline, and at 24- and 48-month follow-up. Two functional paradigms will be used: the Stop-Signal Task to measure motor inhibitory control and a modified version of the Monetary Incentive Delay Task to evaluate reward processing. Discussion: The expected results should help identify biological vulnerability factors, and quantify the consequences of early alcohol abuse as well as the benefits of early intervention using brain metrics