scholarly journals Neural Signatures of Controlled and Automatic Retrieval Processes in Memory-based Decision-making

2016 ◽  
Vol 28 (1) ◽  
pp. 69-83 ◽  
Author(s):  
Patrick H. Khader ◽  
Thorsten Pachur ◽  
Lilian A. E. Weber ◽  
Kerstin Jost

Decision-making often requires retrieval from memory. Drawing on the neural ACT-R theory [Anderson, J. R., Fincham, J. M., Qin, Y., & Stocco, A. A central circuit of the mind. Trends in Cognitive Sciences, 12, 136–143, 2008] and other neural models of memory, we delineated the neural signatures of two fundamental retrieval aspects during decision-making: automatic and controlled activation of memory representations. To disentangle these processes, we combined a paradigm developed to examine neural correlates of selective and sequential memory retrieval in decision-making with a manipulation of associative fan (i.e., the decision options were associated with one, two, or three attributes). The results show that both the automatic activation of all attributes associated with a decision option and the controlled sequential retrieval of specific attributes can be traced in material-specific brain areas. Moreover, the two facets of memory retrieval were associated with distinct activation patterns within the frontoparietal network: The dorsolateral prefrontal cortex was found to reflect increasing retrieval effort during both automatic and controlled activation of attributes. In contrast, the superior parietal cortex only responded to controlled retrieval, arguably reflecting the sequential updating of attribute information in working memory. This dissociation in activation pattern is consistent with ACT-R and constitutes an important step toward a neural model of the retrieval dynamics involved in memory-based decision-making.

2014 ◽  
Author(s):  
Patrick H. Khader ◽  
Thorsten Pachur ◽  
Kerstin Jost ◽  
Lilian A. E. Weber

2017 ◽  
Author(s):  
Eliana Vassena ◽  
James Deraeve ◽  
William H. Alexander

AbstractHuman behavior is strongly driven by the pursuit of rewards. In daily life, however, benefits mostly come at a cost, often requiring that effort be exerted in order to obtain potential benefits. Medial prefrontal cortex (MPFC) and dorsolateral prefrontal cortex (DLPFC) are frequently implicated in the expectation of effortful control, showing increased activity as a function of predicted task difficulty. Such activity partially overlaps with expectation of reward, and has been observed both during decision-making and during task preparation. Recently, novel computational frameworks have been developed to explain activity in these regions during cognitive control, based on the principle of prediction and prediction error (PRO model, Alexander and Brown, 2011, HER Model, Alexander and Brown, 2015). Despite the broad explanatory power of these models, it is not clear whether they can also accommodate effects related to the expectation of effort observed in MPFC and DLPFC. Here, we propose a translation of these computational frameworks to the domain of effort-based behavior. First, we discuss how the PRO model, based on prediction error, can explain effort-related activity in MPFC, by reframing effort-based behavior in a predictive context. We propose that MPFC activity reflects monitoring of motivationally relevant variables (such as effort and reward), by coding expectations, and discrepancies from such expectations. Moreover, we derive behavioral and neural model-based predictions for healthy controls and clinical populations with impairments of motivation. Second, we illustrate the possible translation to effort-based behavior of the HER model, an extended version of PRO model based on hierarchical error prediction, developed to explain MPFC-DLPFC interactions. We derive behavioral predictions which describe how effort and reward information is coded in PFC, and how changing the configuration of such environmental information might affect decision-making and task-performance involving motivation.


2016 ◽  
Vol 23 (1) ◽  
pp. 44-55 ◽  
Author(s):  
Eleni Demetriou ◽  
Roee Holtzer

AbstractObjectives: Mild cognitive impairments (MCI) is a transitional state in aging associated with increased risk of incident dementia. The current study investigated whether MCI status moderated the effect of time on word generation during verbal fluency tasks. Specifically, the objective was to determine whether MCI status had differential effects on initial automatic or latter more effortful retrieval processes of fluency tasks. Methods: Participants were community residing older adults enrolled in a longitudinal cohort study. Of the 408 participants, 353 were normal (age=76.06±6.61; %female=57.8) and 55 were diagnosed with MCI (age=78.62±7.00; %female=52.7). Phonemic and category fluency were each administered for 60 s, but performance was recorded at three consecutive 20-s intervals (0–20 s [T1], 21–40 s [T2], 41–60 s [T3]. Separate linear mixed effects models for each fluency task were used to determine the effects of group, time, and their interaction on word generation. Results: In both fluency tasks, word generation declined as a function of time. Individuals with MCI generated fewer words compared to controls during the first 20 s of phonemic (beta=−1.56; p<.001; d=0.28) and category fluency (beta=−1.85; p<.001; d=0.37). Group by time interactions revealed that individuals with MCI demonstrated attenuated declines in word generation from the first to the second and third time intervals of both phonemic ([T1 vs. T2] beta=2.17, p=.001; d=0.41; [T1 vs. T3]beta=2.28, p=.001; d=0.45) and category ([T1 vs. T2] beta= 2.22, p=.002; d=0.50; [T1 vs. T3]beta=3.16, p<.001; d=0.71) fluency. Conclusions: Early automatic retrieval processes in verbal fluency tasks are compromised in MCI. (JINS, 2017, 23, 44–55)


2016 ◽  
Vol 315 ◽  
pp. 51-65 ◽  
Author(s):  
Joshua J. Tremel ◽  
Patryk A. Laurent ◽  
David A. Wolk ◽  
Mark E. Wheeler ◽  
Julie A. Fiez

2010 ◽  
Vol 22 (3) ◽  
pp. 513-525 ◽  
Author(s):  
Sarah L. Israel ◽  
Tyler M. Seibert ◽  
Michelle L. Black ◽  
James B. Brewer

Hippocampal activity is modulated during episodic memory retrieval. Most consistently, a relative increase in activity during confident retrieval is observed. Dorsolateral prefrontal cortex (DLPFC) is also activated during retrieval, but may be more generally activated during cognitive-control processes. The “default network,” regions activated during rest or internally focused tasks, includes the hippocampus, but not DLPFC. Therefore, DLPFC and the hippocampus should diverge during difficult tasks suppressing the default network. It is unclear, however, whether a difficult episodic memory retrieval task would suppress the default network due to difficulty or activate it due to internally directed attention. We hypothesized that a task requiring episodic retrieval followed by rumination on the retrieved item would increase DLPFC activity, but paradoxically reduce hippocampal activity due to concomitant suppression of the default network. In the present study, blocked and event-related fMRI were used to examine hippocampal activity during episodic memory recollection and postretrieval processing of paired associates. Subjects were asked to make living/nonliving judgments about items visually presented (classify) or items retrieved from memory (recall–classify). Active and passive baselines were used to differentiate task-related activity from default-network activity. During the “recall–classify” task, anterior hippocampal activity was selectively reduced relative to “classify” and baseline tasks, and this activity was inversely correlated with DLPFC. Reaction time was positively correlated with DLPFC activation and default-network/hippocampal suppression. The findings demonstrate that frontal and hippocampal activity are dissociated during difficult episodic retrieval tasks and reveal important considerations for interpreting hippocampal activity associated with successful episodic retrieval.


1999 ◽  
Vol 84 (1) ◽  
pp. 117-120 ◽  
Author(s):  
Christina R. Hale ◽  
Mark V. Gentry ◽  
Charles J. Meliska

10 habitual smokers, aged 19–25 yr., were randomly assigned to smoke either a very low nicotine “Placebo” cigarette (.05-mg nicotine delivery as estimated by the FTC method) or a Nicotine cigarette (.7-mg estimated nicotine delivery). Each participant was asked to abstain from smoking for 4 to 7 hr. prior to testing. After completing a presmoking test of lexical decision-making, participants smoked either a Nicotine or Placebo cigarette and were then retested for reaction times and accuracy on the lexical decision test. When presented the most difficult lexical decisions, participants responded significantly faster after smoking a Nicotine cigarette than they did before smoking; smoking a Placebo cigarette did not affect reaction times. Response accuracy was unaffected by smoking either kind of cigarette. These results suggest that smoking a nicotine cigarette may improve attention or memory retrieval after several hours of smoking abstinence.


2016 ◽  
Author(s):  
Miriam C Klein-Flügge ◽  
Steven W Kennerley ◽  
Karl Friston ◽  
Sven Bestmann

AbstractIntegrating costs and benefits is crucial for optimal decision-making. While much is known about decisions that involve outcome-related costs (e.g., delay, risk), many of our choices are attached to actions and require an evaluation of the associated motor costs. Yet how the brain incorporates motor costs into choices remains largely unclear. We used human functional magnetic resonance imaging during choices involving monetary reward and physical effort to identify brain regions that serve as a choice comparator for effort-reward trade-offs. By independently varying both options' effort and reward levels, we were able to identify the neural signature of a comparator mechanism. A network involving supplementary motor area (SMA) and the caudal portion of dorsal anterior cingulate cortex (dACC) encoded the difference in reward (positively) and effort levels (negatively) between chosen and unchosen choice options. We next modelled effort-discounted subjective values using a novel behavioural model. This revealed that the same network of regions involving dACC and SMA encoded the difference between the chosen and unchosen options' subjective values, and that activity was best described using a concave model of effort-discounting. In addition, this signal reflected how precisely value determined participants' choices. By contrast, separate signals in SMA and ventro-medial PFC (vmPFC) correlated with participants' tendency to avoid effort and seek reward, respectively. This suggests that the critical neural signature of decision-making for choices involving motor costs is found in human cingulate cortex and not vmPFC as typically reported for outcome-based choice. Furthermore, distinct frontal circuits ‘drive’ behaviour towards reward-maximization and effort-minimization.Significance StatementThe neural processes that govern the trade-off between expected benefits and motor costs remain largely unknown. This is striking because energetic requirements play an integral role in our day-to-day choices and instrumental behaviour, and a diminished willingness to exert effort is a characteristic feature of a range of neurological disorders. We use a new behavioural characterization of how humans trade-off reward-maximization with effort-minimization to examine the neural signatures that underpin such choices, using BOLD MRI neuroimaging data. We find the critical neural signature of decision-making, a signal that reflects the comparison of value between choice options, in human cingulate cortex, whereas two distinct brain circuits ‘drive’ behaviour towards reward-maximization or effort-minimization.


2010 ◽  
Vol 22 (4) ◽  
pp. 751-760 ◽  
Author(s):  
Makoto Kusunoki ◽  
Natasha Sigala ◽  
Hamed Nili ◽  
David Gaffan ◽  
John Duncan

The pFC plays a key role in flexible, context-specific decision making. One proposal [Machens, C. K., Romo, R., & Brody, C. D. Flexible control of mutual inhibition: A neural model of two-interval discrimination. Science, 307, 1121–1124, 2005] is that prefrontal cells may be dynamically organized into opponent coding circuits, with competitive groups of cells coding opposite behavioral decisions. Here, we show evidence for extensive, temporally evolving opponent organization in the monkey pFC during a cued target detection task. More than a half of all randomly selected cells discriminated stimulus category in this task. The largest set showed target-positive activity, with the strongest responses to the current target, intermediate activity for a nontarget that was a target on other trials, and lowest activity for nontargets never associated with the target category. Second most frequent was a reverse, antitarget pattern. In the ventrolateral frontal cortex, opponent organization was strongly established in phasic responses at stimulus onset; later, such activity was widely spread across dorsolateral and ventrolateral sites. Task-specific organization into opponent cell groups may be a general feature of prefrontal decision making.


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