Impulsivity and self-control during intertemporal decision making linked to the neural dynamics of reward value representation

A characteristic marker of impulsive decision making is the discounting of delayed rewards, demonstrated via choice preferences and choice-related brain activity. However, delay discounting may also arise from how subjective reward value is dynamically represented in the brain when anticipating an upcoming chosen reward. In the current study, brain activity was continuously monitored as human participants freely selected an immediate or delayed primary liquid reward and then waited for the specified delay before consuming it. The ventromedial prefrontal cortex (vmPFC) exhibited a characteristic pattern of activity dynamics during the delay period, as well as modulation during choice, that is consistent with the time-discounted coding of subjective value. The ventral striatum (VS) exhibited a similar activity pattern, but preferentially in impulsive individuals. A contrasting profile of delay-related and choice activation was observed in the anterior PFC (aPFC), but selectively in patient individuals. Functional connectivity analyses indicated that both vmPFC and aPFC exerted modulatory, but opposite, influences on VS activation. These results link behavioral impulsivity and self-control to dynamically evolving neural representations of future reward value, not just during choice, but also during postchoice delay periods

The role of psychometrics in individual differences research in cognition: A case study of the AX-CPT

Investigating individual differences in cognition requires addressing questions not often thought about in standard experimental designs, especially regarding the psychometric properties of the task. Using the AX-CPT cognitive control task as a case study example, we address four concerns that one may encounter when researching the topic of individual differences in cognition. First, we demonstrate the importance of variability in task scores, which in turn directly impacts reliability, particularly when comparing correlations in different populations. Second, we demonstrate the importance of variability and reliability for evaluating potential failures to replicate predicted correlations, even within the same population. Third, we demonstrate how researchers can turn to evaluating psychometric properties as a way of evaluating the feasibility of utilizing the task in new settings (e.g., online administration). Lastly, we show how the examination of psychometric properties can help researchers make informed decisions when designing a study, such as determining the appropriate number of trials for a task

Brief reports: anticipating the consequences of action: an fMRI study of intention-based task preparation

A key component of task preparation may be to anticipate the consequences of task-appropriate actions. This task switching study examined whether such type of "intentional" preparatory control relies on the presentation of explicit action effects. Preparatory BOLD activation in a condition with task-specific motion effect feedback was compared to identical task conditions with accuracy feedback only. Switch-related activation was found selectively in the effect feedback condition in the middle mid-frontal gyrus and in the anterior intraparietal sulcus. Consistent with research on attentional control, the posterior superior parietal lobule exhibited switch-related preparatory activation irrespective of feedback type. To conclude, preparatory control can occur via complementary attentional and intentional neural mechanisms depending on whether meaningful task-specific action effects lead to the formation of explicit effect representations

Temporal dynamics of motivation-cognitive control interactions revealed by high-resolution pupillometry

Motivational manipulations, such as the presence of performance-contingent reward incentives, can have substantial influences on cognitive control. Previous evidence suggests that reward incentives may enhance cognitive performance specifically through increased preparatory, or proactive, control processes. The present study examined reward influences on cognitive control dynamics in the AX-Continuous Performance Task (AX-CPT), using high-resolution pupillometry. In the AX-CPT, contextual cues must be actively maintained over a delay in order to appropriately respond to ambiguous target probes. A key feature of the task is that it permits dissociable characterization of preparatory, proactive control processes (i.e., utilization of context) and reactive control processes (i.e., target-evoked interference resolution). Task performance profiles suggested that reward incentives enhanced proactive control (context utilization). Critically, pupil dilation was also increased on reward incentive trials during context maintenance periods, suggesting trial-specific shifts in proactive control, particularly when context cues indicated the need to overcome the dominant target response bias. Reward incentives had both transient (i.e., trial-by-trial) and sustained (i.e., block-based) effects on pupil dilation, which may reflect distinct underlying processes. The transient pupillary effects were present even when comparing against trials matched in task performance, suggesting a unique motivational influence of reward incentives. These results suggest that pupillometry may be a useful technique for investigating reward motivational signals and their dynamic influence on cognitive control

Fathers, Divorce, and Child Custody

A great many fathers will have their fathering eliminated, disrupted, or vastly changed because they become divorced from the child’s mother. In fact, between 40% and 50% of marriages end in divorce (Cherlin, 2010). Although the divorce rate (measured as divorces per 1,000 people) is high by the standards prior to the late 1960s, it has actually fallen more than 30% since its peak in 1980. The decline in divorce rates in recent years has, however, been concentrated among the college-educated portion of the population; divorce rates among the less well educated may have even increased (Cherlin, 2010). But for both groups, divorce remains the most prevalent reason for changes in paternal parenting opportunities. For almost all divorced fathers (as well as for most mothers and children), divorce is a life-defining event, around which all other experiences are organized: before the divorce versus after the divorce. Although mothers’ parenting is generally changed by divorce, the revision to the parent-child interaction patterns is generally not as far-reaching as it is to fathers’ (Braver & Lamb, in press; Braver, Shapiro, & Goodman, 2005; Fabricius, Braver, Diaz, & Velez, 2010). The reason, of course, is the radical difference between the two parents’ custodial arrangements that typically occurs. As will be documented more precisely below, mothers generally become chief custodians of children, with fathers having visiting rights only. Although that situation has changed in recent years, due in large part to the fact that research has accumulated that illuminates the unintended negative consequences of that practice on fathers and children, it remains normative. Thus, no review of fathers and divorce can be complete or enlightening unless it also considers custody matters, as we do here

Josephson squelch filter for quantum nanocircuits

We fabricated and tested a squelch circuit consisting of a copper powder filter with an embedded Josephson junction connected to ground. For small signals (squelch-ON), the small junction inductance attenuates strongly from DC to at least 1 GHz, while for higher frequencies dissipation in the copper powder increases the attenuation exponentially with frequency. For large signals (squelch-OFF) the circuit behaves as a regular metal powder filter. The measured ON/OFF ratio is larger than 50dB up to 50 MHz. This squelch can be applied in low temperature measurement and control circuitry for quantum nanostructures such as superconducting qubits and quantum dots.Comment: Corrected and completed references 6,7,8. Updated some minor details in figure

How does reward expectation influence cognition in the human brain?

The prospect of reward changes how we think and behave. We investigated how this occurs in the brain using a novel continuous performance task in which fluctuating reward expectations biased cognitive processes between competing spatial and verbal tasks. Critically, effects of reward expectancy could be distinguished from induced changes in task-related networks. Behavioral data confirm specific bias toward a reward-relevant modality. Increased reward expectation improves reaction time and accuracy in the relevant dimension while reducing sensitivity to modulations of stimuli characteristics in the irrelevant dimension. Analysis of functional magnetic resonance imaging data shows that the proximity to reward over successive trials is associated with increased activity of the medial frontal cortex regardless of the modality. However, there are modality-specific changes in brain activity in the lateral frontal, parietal, and temporal cortex. Analysis of effective connectivity suggests that reward expectancy enhances coupling in both early visual pathways and within the prefrontal cortex. These distributed changes in task-related cortical networks arise from subjects’ representations of future events and likelihood of reward

Task conflict in the Stroop task: When Stroop interference decreases as Stroop facilitation increases in a low task conflict context.

In the present study participants completed two blocks of the Stroop task, one in which the response-stimulus interval (RSI) was 3500 ms and one in which RSI was 200 ms. It was expected that, in line with previous research, the shorter RSI would induce a low Task Conflict context by increasing focus on the color identification goal in the Stroop task and lead to a novel finding of an increase in facilitation and simultaneous decrease in interference. Such a finding would be problematic for models of Stroop effects that predict these indices of performance should be affected in tandem. A crossover interaction is reported supporting these predictions. As predicted, the shorter RSI resulted in incongruent and congruent trial reaction times (RTs) decreasing relative to a static neutral baseline condition; hence interference decreased as facilitation increased. An explanatory model (expanding on the work of Goldfarb and Henik, 2007) is presented that: (1) Shows how under certain conditions the predictions from single mechanism models hold true (i.e., when Task conflict is held constant); (2) Shows how it is possible that interference can be affected by an experimental manipulation that leaves facilitation apparently untouched; and (3) Predicts that facilitation cannot be independently affected by an experimental manipulation

Mind over memory: cueing the aging brain

A decline in recollection is a hallmark of even healthy aging and is associated with wider impairments in mental control. Older adults have difficulty internally directing thought and action in line with their goals, and often rely more on external cues. To assess the impact this has on memory, emerging brain-imaging and behavioral approaches investigate the operation and effectiveness of goal-directed control before information is retrieved. Current data point to effects of aging at more than one stage in this process, particularly in the face of competing goals. These effects may reflect wider changes in the proactive, self-initiated regulation of thought and action. Understanding them is essential for establishing whether internal “self-cuing” of memory can be improved, and whether—and when—it is best to use environmental support from external cues to maximize memory performance

Prefrontal control of familiarity and recollection in working memory

Left inferior frontal gyrus (IFG) is a critical neural substrate for the resolution of proactive interference (PI) in working memory. We hypothesized that left IFG achieves this by controlling the influence of familiarity- versus recollection-based information about memory probes. Consistent with this idea, we observed evidence for an early (200 msec)-peaking signal corresponding to memory probe familiarity and a late (500 msec)-resolving signal corresponding to full accrual of trial-related contextual ("recollection-based") information. Next, we applied brief trains of repetitive transcranial magnetic stimulation (rTMS) time locked to these mnemonic signals, to left IFG and to a control region. Only early rTMS of left IFG produced a modulation of the false alarm rate for high-PI probes. Additionally, the magnitude of this effect was predicted by individual differences in susceptibility to PI. These results suggest that left IFG-based control may bias the influence of familiarity- and recollection-based signals on recognition decisions