Showing papers by "Todd S. Braver published in 2012"
TL;DR: Recent research is summarized that demonstrates how the DMC framework provides a coherent explanation of three sources of cognitive control variation - intra-individual, inter-individual and between-groups - in terms of proactive versus reactive control biases.
1,742 citations
TL;DR: Global connectivity in this LPFC region showed a highly selective relationship with individual differences in fluid intelligence, suggesting LPFC is a global hub with a brainwide influence that facilitates the ability to implement control processes central to human intelligence.
Abstract: Control of thought and behavior is fundamental to human intelligence. Evidence suggests a frontoparietal brain network implements such cognitive control across diverse contexts. We identify a mechanism--global connectivity--by which components of this network might coordinate control of other networks. A lateral prefrontal cortex (LPFC) region's activity was found to predict performance in a high control demand working memory task and also to exhibit high global connectivity. Critically, global connectivity in this LPFC region, involving connections both within and outside the frontoparietal network, showed a highly selective relationship with individual differences in fluid intelligence. These findings suggest LPFC is a global hub with a brainwide influence that facilitates the ability to implement control processes central to human intelligence.
571 citations
TL;DR: Activity patterns in lateral PFC were consistent with a third possible account that postulates that both posterior and anterior regions of PFC are reliably engaged in task conditions requiring active maintenance of contextual information, with the temporal dynamics of activity in these regions flexibly tracking the duration of maintenance demands.
Abstract: The present experiment tested three hypotheses regarding the function and organization of lateral prefrontal cortex (PFC). The first account (the information cascade hypothesis) suggests that the anterior-posterior organization of lateral PFC is based on the timing with which cue stimuli reduce uncertainty in the action selection process. The second account (the levels-of-abstraction hypothesis) suggests that the anterior-posterior organization of lateral PFC is based on the degree of abstraction of the task goals. The current study began by investigating these two hypotheses, and identified several areas of lateral PFC that were predicted to be active by both the information cascade and levels-of-abstraction accounts. However, the pattern of activation across experimental conditions was inconsistent with both theoretical accounts. Specifically, an anterior area of mid-dorsolateral PFC exhibited sensitivity to experimental conditions that, according to both accounts, should have selectively engaged only posterior areas of PFC. We therefore investigated a third possible account (the adaptive context maintenance hypothesis) that postulates that both posterior and anterior regions of PFC are reliably engaged in task conditions requiring active maintenance of contextual information, with the temporal dynamics of activity in these regions flexibly tracking the duration of maintenance demands. Activity patterns in lateral PFC were consistent with this third hypothesis: regions across lateral PFC exhibited transient activation when contextual information had to be updated and maintained in a trial-by-trial manner, but sustained activation when contextual information had to be maintained over a series of trials. These findings prompt a reconceptualization of current views regarding the anterior-posterior organization of lateral PFC, but do support other findings regarding the active maintenance role of lateral PFC in sequential working memory paradigms.
68 citations
TL;DR: The review suggests that the neuro-cognitive systems involved in the preparation of novel plans are different than those involved in preparation of practiced plans (i.e., those that have been executed beforehand).
Abstract: In this review, the authors discuss the seemingly paradoxical loss of control associated with states of high readiness to execute a plan, termed “intention-based reflexivity.” The review suggests that the neuro-cognitive systems involved in the preparation of novel plans are different than those involved in preparation of practiced plans (i.e., those that have been executed beforehand). When the plans are practiced, intention-based reflexivity depends on the prior availability of response codes in long-term memory (LTM). When the plans are novel, reflexivity is observed when the plan is pending and the goal has not yet been achieved. Intention-based reflexivity also depends on the availability of working-memory (WM) limited resources and the motivation to prepare. Reflexivity is probably related to the fact that, unlike reactive control (once a plan is prepared), proactive control tends to be relatively rigid.
60 citations
TL;DR: The hypothesis that L-aPFC is causally and selectively involved in the integration of information in working memory is confirmed and it is suggested that pre-integration loading and post-Integration unloading of information involving this area may be active and resource-consuming processes.
Abstract: Integration is a fundamental working memory operation, requiring the insertion of information from one task into the execution of another concurrent task. Previous neuroimaging studies have suggested the involvement of left anterior prefrontal cortex (L-aPFC) in relation to working memory integration demands, increasing during presentation of information to be integrated (loading), throughout its maintenance during a secondary task, up to the integration step, and then decreasing afterward (unloading). Here we used short bursts of 5 Hz repetitive Transcranic Magnetic Stimulation (rTMS) to modulate L-aPFC activity and to assess its causal role in integration. During experimental blocks, rTMS was applied (N=10) over L-aPFC or vertex (control site) at different time-points of a task involving integration of a preloaded digit into a sequence of arithmetical steps, and contrasted with a closely matched task without integration demand (segregation). When rTMS was applied during the loading phase, reaction times during secondary task were faster, without significant changes in error rates. RTMS instead worsened performance when applied during information unloading. In contrast, no effects were observed when rTMS was applied during the other phases of integration, or during the segregation condition. These results confirm the hypothesis that L-aPFC is causally and selectively involved in the integration of information in working memory. They additionally suggest that pre-integration loading and post-integration unloading of information involving this area may be active and resource-consuming processes.
14 citations
TL;DR: It is suggested that strategy training can diminish RA, but that training efficacy is reduced among OAs, potentially due to goal neglect, and implications for neural mechanisms that may distinguish older and YAs’ risky decision-making.
Abstract: Maximizing long-run gains often requires taking on some degree of risk, yet decision-makers often exhibit risk aversion (RA), rejecting risky prospects even when these have higher expected value than safer alternatives. We investigated whether explicit strategy instruction and practice can decrease prepotent RA, and whether aging impacts the efficacy of such an intervention. Participants performed a paired lottery task with options varying in risk and magnitude, both before and after practice with a similar task that encouraged maximization of expected value and instruction to use this strategy in risky decisions. In both younger and older adults, strategy training reduced RA. Although RA was age-equivalent at baseline, larger training effects were observed in younger adults. These effects were not explained by risk-related (i.e., affective) interference effects or computation ability, but were consistent with a progressive, age-related neglect of the strategy across trials. Our findings suggest that strategy training can diminish RA, but that training efficacy is reduced among older adults, potentially due to goal-neglect. We discuss implications for neural mechanisms that may distinguish older and younger adults’ risky decision-making.
11 citations
TL;DR: This work found dissociations between local and global motivational effects that were linked to specific properties of the incentive signals (i.e., timing), while also ruling out alternative interpretations (e.g., practice and speed—accuracy trade-off effects).
Abstract: Motivation has been found to enhance cognitive control, but the mechanisms by which this occurs are still poorly understood. Cued motivational incentives (e.g., monetary rewards) can modulate cognitive processing locally—that is, on a trial-by-trial basis (incentive cue effect). Recently, motivational incentives have also been found to produce more global and tonic changes in performance, as evidenced by performance benefits on nonincentive trials occurring within incentive blocks (incentive context effect). In two experiments involving incentivized cued task switching, we provide systematic evidence that the two effects are dissociable. Through behavioral, diffusion-modeling, and individual-differences analyses, we found dissociations between local and global motivational effects that were linked to specific properties of the incentive signals (i.e., timing), while also ruling out alternative interpretations (e.g., practice and speed—accuracy trade-off effects). These results provide important clues regarding the neural mechanisms by which motivation exerts both global and local influences on cognitive control.
4 citations