Prefrontal Set Activity Predicts Rule-Specific Neural Processing during Subsequent Cognitive Performance

569

677

A major challenge in research on executive control is to reveal its functional decomposition into underlying neural mechanisms. A typical assumption is that this decomposition occurs solely through anatomically based dissociations. Here we tested an alternative hypothesis that different cognitive control processes may be implemented within the same brain regions, with fractionation and dissociation occurring on the basis of temporal dynamics. Regions within lateral prefrontal cortex (PFC) were examined that, in a prior study, exhibited contrasting temporal dynamics between older and younger adults during performance of the AX-CPT cognitive control task. The temporal dynamics in younger adults fit a proactive control pattern (primarily cue-based activation), whereas in older adults a reactive control pattern was found (primarily probebased activation). In the current study, we found that following a period of task-strategy training, these older adults exhibited a proactive shift within a subset of the PFC regions, normalizing their activity dynamics toward young adult patterns. Conversely, under conditions of penalty-based monetary incentives, the younger adults exhibited a reactive shift some of the same regions, altering their temporal dynamics toward the older adult baseline pattern. These experimentally induced crossover patterns of temporal dynamics provide strong support for dual modes of cognitive control that can be flexibly shifted within PFC regions, via modulation of neural responses to changing task conditions or behavioral goals.dorsolateral PFC ͉ event-related fMRI ͉ inhibition ͉ interference control ͉ working memory

Section: Discussionsupporting

confidence: 79%

Flexible neural mechanisms of cognitive control within human prefrontal cortex

Braver

Paxton

Locke

et al. 2009

569

677

“…Previous studies reported that the dorsolateral PFC participates in a range of processes related to executive behavioral control (32)(33)(34)(35). Among them, the role of the lateral PFC in response-guiding rules and strategies is of particular relevance to the present study.…”

Section: Discussionmentioning

confidence: 78%

Neuronal activity in the primate dorsomedial prefrontal cortex contributes to strategic selection of response tactics

Matsuzaka

Akiyama

Tanji

et al. 2012

The functional roles of the primate posterior medial prefrontal cortex have remained largely unknown. Here, we show that this region participates in the regulation of actions in the presence of multiple response tactics. Monkeys performed a forelimb task in which a visual cue required prompt decision of reaching to a left or a right target. The location of the cue was either ipsilateral (concordant) or contralateral (discordant) to the target. As a result of extensive training, the reaction times for the concordant and discordant trials were indistinguishable, indicating that the monkeys developed tactics to overcome the cue-response conflict. Prefrontal neurons exhibited prominent activity when the concordant and discordant trials were randomly presented, requiring rapid selection of a response tactic (reach toward or away from the cue). The following findings indicate that these neurons are involved in the selection of tactics, rather than the selection of action or monitoring of response conflict: (i) The response period activity of neurons in this region disappeared when the monkeys performed the task under the behavioral condition that required a single tactic alone, whereas the action varied across trials. (ii) The neuronal activity was found in the dorsomedial prefrontal cortex but not in the anterior cingulate cortex that has been implicated for the response conflict monitoring. These results suggest that the medial prefrontal cortex participates in the selection of a response tactic that determines an appropriate action. Furthermore, the observation of dynamic, task-dependent neuronal activity necessitates reconsideration of the conventional concept of cortical motor representation.cortical plasticity | frontal executive function T he primate dorsomedial prefrontal cortex (PFC), and particularly its posterior region (pmPFC), is intimately connected with higher-order cortical motor areas in the frontal lobe, including the presupplementary motor area (pre-SMA), the rostral cingulate motor area, and the dorsal premotor area (1-4). This relationship with cortical motor areas resembles connections from the dorsolateral PFC (dlPFC), suggesting that both areas influence downstream motor areas during the selection, preparation, and execution of actions (5-8). Despite numerous studies demonstrating the involvement of the dlPFC in various aspects of behavioral control (9-12), however, little is known about the role of the pmPFC in the performance of motor behaviors.A few studies have attempted to explore this area. For example, Petrides proposed that the dorsomedial PFC plays important roles in monitoring multiple events and self-ordering actions (13), although his later study suggested that the dlPFC is also involved in this process (14). Bon and Lucchetti reported that electrical stimulation in area 8b evoked ear or eye movements, and neurons in this region showed activity modulation related to these types of movements (15, 16). Human brain-imaging studies identified active areas including the mPFC that were re...

“…1B, Left and SI Materials and Methods). Most importantly, this network included color-sensitive area V4 and motion-sensitive area hMT, as well as a number of frontal and parietal areas previously associated with task preparation and top-down attentional control (6,7,(30)(31)(32)(33). The preparatory network was used to derive 70 spherical, nonoverlapping network nodes (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…During goal-directed behavior, like the preparation of an upcoming task, relevant cortical regions are anticipatorily modulated (1)(2)(3)(4)(5), which has been shown to facilitate the detection and analysis of task-relevant stimuli (6)(7)(8)(9)(10)(11)(12)(13).…”

mentioning

confidence: 99%

Predicting errors from reconfiguration patterns in human brain networks

Ekman

Derrfuß

Tittgemeyer

et al. 2012

157

143

Task preparation is a complex cognitive process that implements anticipatory adjustments to facilitate future task performance.Little is known about quantitative network parameters governing this process in humans. Using functional magnetic resonance imaging (fMRI) and functional connectivity measurements, we show that the large-scale topology of the brain network involved in task preparation shows a pattern of dynamic reconfigurations that guides optimal behavior. This network could be decomposed into two distinct topological structures, an error-resilient core acting as a major hub that integrates most of the network's communication and a predominantly sensory periphery showing more flexible network adaptations. During task preparation, core-periphery interactions were dynamically adjusted. Task-relevant visual areas showed a higher topological proximity to the network core and an enhancement in their local centrality and interconnectivity. Failure to reconfigure the network topology was predictive for errors, indicating that anticipatory network reconfigurations are crucial for successful task performance. On the basis of a unique network decoding approach, we also develop a general framework for the identification of characteristic patterns in complex networks, which is applicable to other fields in neuroscience that relate dynamic network properties to behavior. graph theory | attention | cognitive control T he human brain forms a highly complex network that is organized into a large number of specialized regions. During goal-directed behavior, like the preparation of an upcoming task, relevant cortical regions are anticipatorily modulated (1-5), which has been shown to facilitate the detection and analysis of task-relevant stimuli (6-13).However, little is known about how these task-specific adjustments are integrated across distinct brain regions and how preparatory mechanisms are reflected in a large-scale network topology (14-16). It has been shown that attention can modulate interarea correlations between distant cortical regions, independent from changes in regional blood flow (17-19). However, these studies were usually limited to a small selection of cortical regions (2,7,15,(18)(19)(20). With recent developments in functional connectivity analysis, it has become possible to study the role of large-scale networks for cognitive processing and to quantify network properties using global and local graph theoretical measures (21-26).On the one hand, task preparation involves dynamic adjustments in regions that carry out computations that are specific to a given task. On the other hand, it also requires the stable maintenance of task goals (7) and reconfigurations of the network based on these goals. Given these characteristics and the organization of brain networks into modules with distinct functional properties (27, 28), we hypothesized that task-specific processes, whose involvement varies from trial to trial, are reflected in dynamic adjustments of more peripheral components of the brain network. We...