Differential Neural Activation for Updating Rule versus Stimulus Information in Working Memory

Montojo, Caroline A.; Courtney, Susan

doi:10.1016/j.neuron.2008.05.012

Cited by 56 publications

(53 citation statements)

References 37 publications

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“…The preferential involvement of SPL in item processing is consistent with earlier work in our lab (Montojo and Courtney 2008) and with its known role in directing spatial attention (Yantis et al 2002). [It is likely that the SPL is involved in relational (and rule) encoding as well as item but to a lesser extent, because relational information can be converted into an abstract format.]…”

Section: Discussionsupporting

confidence: 89%

“…An earlier study from our lab found a very similar area selectively activated for the updating of rule (compared with item) information in working memory [Montojo and Courtney 2008;see also Brass and von Cramon (2004) for more evidence that this region is implicated in updating of task rules]. Whereas we could not decode the representational content of relations in this region in the current study, the close concordance between the two studies suggests at least that there may be commonalities between rule and relational processing that recruit this region.…”

Section: Discussionmentioning

confidence: 71%

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Spatial relations and spatial locations are dissociated within prefrontal and parietal cortex

Ackerman

Courtney

2012

Journal of Neurophysiology

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Ackerman CM, Courtney SM. Spatial relations and spatial locations are dissociated within prefrontal and parietal cortex. J Neurophysiol 108: 2419 -2429. First published August 15, 2012 doi:10.1152/jn.01024.2011.-Item-specific spatial information is essential for interacting with objects and for binding multiple features of an object together. Spatial relational information is necessary for implicit tasks such as recognizing objects or scenes from different views but also for explicit reasoning about space such as planning a route with a map and for other distinctively human traits such as tool construction. To better understand how the brain supports these two different kinds of information, we used functional MRI to directly contrast the neural encoding and maintenance of spatial relations with that for item locations in equivalent visual scenes. We found a double dissociation between the two: whereas item-specific processing implicates a frontoparietal attention network, including the superior frontal sulcus and intraparietal sulcus, relational processing preferentially recruits a cognitive control network, particularly lateral prefrontal cortex (PFC) and inferior parietal lobule. Moreover, pattern classification revealed that the actual meaning of the relation can be decoded within these same regions, most clearly in rostrolateral PFC, supporting a hierarchical, representational account of prefrontal organization.fMRI; representation; hierarchical organization; reasoning WHEREAS MOST RESEARCH INTO the neural basis of spatial processing has focused on the representation of object location in eye-, head-, or hand-centered coordinates, in much of daily life and language use, it is the relative positions between objects that is critical. For instance, view-independent object recognition depends on knowledge of the spatial relations between object parts. This could be accomplished implicitly, but explicit representation of the spatial relations between entities in the environment is necessary for communication about space beyond mere pointing, for creating tools and symbols composed of multiple independent elements, and for map-based navigation.The prefrontal cortex (PFC) would be expected to be involved in tasks requiring explicit encoding and maintenance of object locations and spatial relations in working memory. Several theories of PFC organization suggest that more abstract or integrated information is represented more anteriorly than more concrete, sensorimotor information [see Badre (2008) As relations are abstracted away from object-bound features and require integration among multiple objects, such theories would predict that in a direct comparison with object location, spatial relations between objects would be represented in more rostral regions.

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Section: Discussionsupporting

confidence: 89%

Section: Discussionmentioning

confidence: 71%

Spatial relations and spatial locations are dissociated within prefrontal and parietal cortex

Ackerman

Courtney

2012

Journal of Neurophysiology

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“…This finding underlines the crucial role of dlPFC in driving functional integration in the WM network. This is in line with a recent fMRI study demonstrating that rule updating preferentially activates prefrontal cortex and stimulus updating activates PC in healthy participants (Montojo and Courtney, 2008). The n-back task used in our study requires participants to update rules, 2-back versus 0-back, as well as continuous stimulus updating of numbers presented within each block.…”

Section: Prefrontal Activation and Cognitive Performancesupporting

confidence: 88%

Reduced Prefrontal-Parietal Effective Connectivity and Working Memory Deficits in Schizophrenia

et al. 2012

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The neural mechanisms behind cognitive deficits in schizophrenia still remain unclear. Functional neuroimaging studies on working memory (WM) yielded inconsistent results, suggesting task performance as a moderating variable of prefrontal activation. Beyond regional specific activation, disordered integration of brain regions was supposed as a critical pathophysiological mechanism of cognitive deficits in schizophrenia. Here, we first hypothesized that prefrontal activation implicated in WM depends primarily on task performance and therefore stratified participants into performance subgroups. Second, in line with the dysconnectivity hypothesis, we asked whether connectivity in the prefrontal-parietal network underlying WM is altered in all patients. We used functional magnetic resonance imaging in human subjects (41 schizophrenia patients, 42 healthy controls) and dynamic causal modeling to examine effective connectivity during a WM task. In line with our first hypothesis, we found that prefrontal activation was differentially modulated by task performance: there was a significant task by group by performance interaction revealing an increase of activation with performance in patients and a decrease with performance in controls. Beyond that, we show for the first time that WM-dependent effective connectivity from prefrontal to parietal cortex is reduced in all schizophrenia patients. This finding was independent of performance. In conclusion, our results are in line with the highly influential hypothesis that the relationship between WM performance and prefrontal activation follows an inverted U-shaped function. Moreover, this study in a large sample of patients reveals a mechanism underlying prefrontal inefficiency and cognitive deficits in schizophrenia, thereby providing direct experimental evidence for the dysconnectivity hypothesis.

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“…It is thus unlikely that this lPFC region is primarily involved in the short-term storage of memory set items, but instead is more related to maintenance of goal-related information needed for successful performance, such as task sets or rules (29). Indeed, recent empirical work has suggested that lateral PFC is preferentially involved in active maintenance of goal-related information (30)(31)(32)(33)(34)(35). Interestingly, PFC neurons also code information related to the reward context (3,7,36).…”

Section: Discussionmentioning

confidence: 99%

Prefrontal cortex mediation of cognitive enhancement in rewarding motivational contexts

Jimura¹,

Locke²,

Braver

2010

Proc. Natl. Acad. Sci. U.S.A.

257

301

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Increasing the reward value of behavioral goals can facilitate cognitive processes required for goal achievement. This facilitation may be accomplished by the dynamic and flexible engagement of cognitive control mechanisms operating in distributed brain regions. It is still not clear, however, what are the characteristics of individuals, situations, and neural activation dynamics that optimize motivation-linked cognitive enhancement. Here we show that highly reward-sensitive individuals exhibited greater improvement of working memory performance in rewarding contexts, but exclusively on trials that were not rewarded. This effect was mediated by a shift in the temporal dynamics of activation within right lateral prefrontal cortex, from a transient to predominantly tonic mode, with an additional anticipatory transient boost. In contexts with intermittent rewards, a strategy of proactive cognitive control may enable globally optimal performance to facilitate reward attainment. Reward-sensitive individuals appear preferentially motivated to adopt this resource-demanding strategy, resulting in paradoxical benefits selectively for nonrewarded events.executive function | personality | working memory | dopamine | mixed blocked/event-related fMRI I n some task situations, successful behavioral performance leads to the potential for a highly rewarding outcome (e.g., gambling games, college entrance exams, sales contests) . When motivational salience is high, the increased value of the behavioral goal to be achieved needs to be translated into an optimal cognitive strategy (1-3). Previous experimental evidence suggests that such a translation does occur, because both cognitive performance and brain activity are enhanced in behavioral situations paired with motivational incentives (e.g., monetary rewards) (4-11). Importantly, these behavioral and neural enhancements have been found to be associated with the potential reward value available on specific trials. However, there is still very little knowledge regarding the specific behavioral situations, neural mechanisms, and individual trait factors that are critical for such enhancement effects.We have postulated a theoretical framework, known as the Dual Mechanisms of Control (DMC; ref. 12), that distinguishes two cognitive control modes, proactive and reactive (Fig. S1A). The former is characterized by sustained active maintenance and/or anticipatory implementation of behavioral goals in the lateral prefrontal cortex (lPFC) (13,14), whereas the latter is characterized by transient, bottom-up updating of goal-relevant information within a wider brain network (15). In previous work, we have demonstrated that the DMC model predicts age-related and incentive-dependent shifts in activation dynamics in the lPFC (16-18). However, a limitation of the prior work has been the lack of a conclusive demonstration that experimental and individual differences effects in cognitive control modes are both functionally mediated by a shift in the activation dynamics within lPFC. In the current...

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Differential Neural Activation for Updating Rule versus Stimulus Information in Working Memory

Cited by 56 publications

References 37 publications

Spatial relations and spatial locations are dissociated within prefrontal and parietal cortex

Spatial relations and spatial locations are dissociated within prefrontal and parietal cortex

Reduced Prefrontal-Parietal Effective Connectivity and Working Memory Deficits in Schizophrenia

Prefrontal cortex mediation of cognitive enhancement in rewarding motivational contexts

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