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Neural evidence for dissociable components of task-switching
- Cerebral Cortex
, 2006
"... The ability to retrieve and flexibly switch between task rules is seen as an important component of cognitive control. It is often assumed that lateral prefrontal cortex (latPFC) is important for switching between rules. However, activation associated with rule-switching is less reliably observed in ..."
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Cited by 49 (6 self)
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The ability to retrieve and flexibly switch between task rules is seen as an important component of cognitive control. It is often assumed that lateral prefrontal cortex (latPFC) is important for switching between rules. However, activation associated with rule-switching is less reliably observed in latPFC than in medial PFC (specifically, pre-supplementary motor area). In this study, we tested the hypothesis that medial PFC is important for reconfigura-tion of task sets, whereas latPFC is important for retrieving, maintaining and implementing relevant rules (i.e. rule representa-tion). Twenty young adults participated in a functional magnetic resonance imaging study in which they determined the correct response to a target stimulus on the basis of an instructional cue. For bivalent targets, the appropriate response depended on the currently relevant rule. In contrast, univalent targets were always associated with the same response. Brain regions of interest were characterized according to their responsiveness to bivalent and univalent targets, on both rule-switch and rule-repetition trials. The data support the hypothesis that rule representation and task-set reconfiguration are separable cognitive processes, associated with dissociable neural activation in latPFC and medial PFC, respec-tively. Activation profiles of posterior parietal cortex, basal ganglia and rostrolateral PFC are also examined and discussed.
Two modes of sensorimotor integration in intention-based and stimulus-based actions. The Quarterly
- Journal of Experimental Psychology
, 2007
"... Human actions may be driven endogenously (to produce desired environmental effects) or exogenously (to accommodate to environmental demands). There is a large body of evidence indicating that these two kinds of action are controlled by different neural substrates. However, only little is known about ..."
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Cited by 29 (8 self)
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Human actions may be driven endogenously (to produce desired environmental effects) or exogenously (to accommodate to environmental demands). There is a large body of evidence indicating that these two kinds of action are controlled by different neural substrates. However, only little is known about what happens—in functional terms—on these different “routes to action”. Ideomotor approaches claim that actions are selected with respect to their perceptual consequences. We report experiments that support the validity of the ideomotor principle and that, at the same time, show that it is subject to a far-reaching constraint: It holds for endogenously driven actions only! Our results suggest that the activity of the two “routes to action ” is based on different types of learning: The activity of the system guiding stimulus-based actions is accompanied by stimulus–response (sensorimotor) learning, whereas the activity of the system controlling intention-based actions results in action–effect (ideomotor) learning. There are two principal ways in which humans can interact with their environment. They may either carry out movements to manipulate the environ-ment in order to produce desired environmental effects, or carry out movements to accommodate
Prefrontal and hippocampal contributions to visual associative recognition: interactions between cognitive control and episodic retrieval. Brain Cogn.
, 2004
"... Abstract The ability to recover episodic associations is thought to depend on medial-temporal lobe mnemonic mechanisms and frontal lobe cognitive control processes. The present study examined the neural circuitry underlying non-verbal associative retrieval, and considered the consequences of succes ..."
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Cited by 27 (1 self)
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Abstract The ability to recover episodic associations is thought to depend on medial-temporal lobe mnemonic mechanisms and frontal lobe cognitive control processes. The present study examined the neural circuitry underlying non-verbal associative retrieval, and considered the consequences of successful retrieval on cognitive control demands. Event-related fMRI data were acquired while subjects retrieved strongly or weakly associated pairs of novel visual patterns in a two-alternative forced choice associative recognition paradigm. Behaviorally, successful retrieval of strongly associated relative to weakly associated pairs was more likely to be accompanied by conscious recollection of the pairÕs prior co-occurrence. At the neural level, right ventrolateral prefrontal cortex (VLPFC) and hippocampus were more active during successful retrieval of Strong than of Weak associations, consistent with a role in visual associative recollection. By contrast, Weak trials elicited greater activation in right anterior cingulate cortex (ACC), which may detect conflict between the similarly familiar target and foil stimuli in the absence of recollection. Consistent with this interpretation, stronger ACC activity was associated with weaker hippocampal and stronger right dorsolateral PFC (DLPFC) responses. Thus, recollection of relevant visual associations (hippocampus and VLPFC) results in lower levels of mnemonic conflict (ACC) and decreased familiarity-based monitoring demands (DLPFC). These findings highlight the interplay between cognitive control and episodic retrieval.
Cortical Connections of the Macaque Anterior Intraparietal (AIP) Area
- CEREBRAL CORTEX
, 2007
"... We traced the cortical connections of the anterior intraparietal (AIP) area, which is known to play a crucial role in visuomotor transformations for grasping. AIP displayed major connections with 1) areas of the inferior parietal lobule convexity, the rostral part of the lateral intraparietal area a ..."
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Cited by 24 (6 self)
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We traced the cortical connections of the anterior intraparietal (AIP) area, which is known to play a crucial role in visuomotor transformations for grasping. AIP displayed major connections with 1) areas of the inferior parietal lobule convexity, the rostral part of the lateral intraparietal area and the SII region; 2) ventral visual stream areas of the lower bank of the superior temporal sulcus and the middle temporal gyrus; and 3) the premotor area F5 and prefrontal areas 46 and 12. Additional connections were observed with the caudal intraparietal area and the ventral part of the frontal eye field. This study suggests that visuomotor transformations for object-oriented actions, processed in AIP, rely not only on dorsal visual stream information related to the object’s physical properties but also on ventral visual stream information related to object identity. The identification of direct anatomical connections with the inferotemporal cortex suggests that AIP also has a unique role in linking the parietofrontal network of areas involved in sensorimotor transformations for grasping with areas involved in object recognition. Thus, AIP could represent a crucial node in a cortical circuit in which hand-related sensory and motor signals gain access to representations of object identity for tactile object recognition.
Multiple movement representations in the human brain: an event-related fMRI study
- J. Cogn. Neurosci
, 2002
"... & Neurovascular correlates of response preparation have been investigated in human neuroimaging studies. However, conventional neuroimaging cannot distinguish, within the same trial, between areas involved in response selection and/ or response execution and areas specifically involved in respon ..."
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Cited by 21 (5 self)
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& Neurovascular correlates of response preparation have been investigated in human neuroimaging studies. However, conventional neuroimaging cannot distinguish, within the same trial, between areas involved in response selection and/ or response execution and areas specifically involved in response preparation. The specific contribution of parietal and frontal areas to motor preparation has been explored in electrophysiological studies in monkey. However, the asso-ciative nature of sensorimotor tasks calls for the additional contributions of other cortical regions. In this article, we have investigated the functional anatomy of movement represen-tations in the context of an associative visuomotor task with instructed delays. Neural correlates of movement representa-tions have been assessed by isolating preparatory activity that
Resolving dual-task interference: An fMRI study. Neuroimage 22: 748–754
, 2004
"... The human cognitive system is severely limited in the amount of information it can process simultaneously. When two tasks are presented within a short stimulus-onset-asynchrony (SOA), reaction time of each task, especially task 2, is dramatically delayed. Previous studies have shown that such delay ..."
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Cited by 19 (0 self)
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The human cognitive system is severely limited in the amount of information it can process simultaneously. When two tasks are presented within a short stimulus-onset-asynchrony (SOA), reaction time of each task, especially task 2, is dramatically delayed. Previous studies have shown that such delay is accompanied by increased activation in the right inferior frontal gyrus (GFi). In this study, we address the role of right GFi in resolving dual-task interference at two different stages: allocation of perceptual attention and response selection. We scan 12 subjects using functional MRI while they conduct two tasks—shape discrimination in task 1 and color discrimination in task 2—and vary the SOA between tasks as 100 or 1500 ms. The targets are located at the center or at the periphery. When both are at the center, they compete primarily for response selection. When both are at the periphery, they additionally compete for the allocation of perceptual attention. Results show that the right GFi and frontal operculum regions are significantly more active in the short SOA than the long SOA condition, but only when subjects attend to the periphery in both tasks. We conclude that the right lateral frontal regions are important for resolving dual-task interference at the perceptual attention stage.
On the neural control of social emotional behavior
- Soc. Cogn. Affect. Neurosci
, 2009
"... It is known that the orbitofrontal cortex (OFC) is crucially involved in emotion regulation. However, the specific role of the OFC in controlling the behavior evoked by these emotions, such as approach–avoidance (AA) responses, remains largely unexplored. We measured behavioral and neural responses ..."
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Cited by 19 (6 self)
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It is known that the orbitofrontal cortex (OFC) is crucially involved in emotion regulation. However, the specific role of the OFC in controlling the behavior evoked by these emotions, such as approach–avoidance (AA) responses, remains largely unexplored. We measured behavioral and neural responses (using fMRI) during the performance of a social task, a reaction time (RT) task where subjects approached or avoided visually presented emotional faces by pulling or pushing a joystick, respectively. RTs were longer for affect-incongruent responses (approach angry faces and avoid happy faces) as compared to affect-congruent responses (approach–happy; avoid–angry). Moreover, affect-incongruent responses recruited increased activity in the left lateral OFC. These behavioral and neural effects emerged only when the subjects responded explicitly to the emotional value of the faces (AA-task) and largely disappeared when subjects responded to an affectively irrelevant feature of the faces during a control (gender evaluation: GE) task. Most crucially, the size of the OFC-effect correlated positively with the size of the behavioral costs of approaching angry faces. These findings qualify the role of the lateral OFC in the voluntary control of social–motivational behavior, emphasizing the relevance of this region for selecting rule-driven stimulus–response associations, while overriding automatic (affect-congruent) stimulus–response mappings.
The effects of prefrontal lesions on working memory performance and theory
- Cognitive, Affective, & Behavioral Neuroscience
, 2004
"... The effects of experimental lesions of the monkey prefrontal cortex have played a predominant role in current conceptualizations of the functional organization of the lateral prefrontal cortex, especially with regard to working memory. The loss or sparing of certain performance abilities has been sh ..."
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Cited by 16 (2 self)
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The effects of experimental lesions of the monkey prefrontal cortex have played a predominant role in current conceptualizations of the functional organization of the lateral prefrontal cortex, especially with regard to working memory. The loss or sparing of certain performance abilities has been shown to be attributable to differences in the specific requirements of behavioral testing (e.g., spatial vs. nonspatial memoranda) along with differences in the specific locations of applied ablations (e.g., dorsal vs. ventral prefrontal cortex). Such findings, which have accumulated now for over a century, have led to widespread acceptance that the dorsolateral and ventrolateral aspects of the prefrontal cortex may perform different, specialized roles in higher order cognition. Nonetheless, it remains unclear and controversial how the lateral prefrontal cortex is functionally organized. Two main views propose different types of functional specialization of the dorsal and ventral prefrontal cortex. The first contends that the lateral prefrontal cortex is segregated according to the processing of spatial and nonspatial domains of information. The second contends that domain specialization is not the key to the organization of the prefrontal cortex, but that instead, the dorsal and ventral prefrontal cortices perform qualitatively different operations. This report critically reviews all relevant monkey lesion studies that have served as the foundation for current theories regarding the functional organization of the prefrontal
Retrieving rules for behavior from long-term memory. Manuscript submitted for publication.
, 2004
"... Human behavior is often dictated by rules or prescribed guides for action. Little is currently known regarding how these rules are stored in long-term memory or retrieved and implemented. Here, we examined the roles of ventrolateral prefrontal cortex (VLPFC) and posterior middle temporal gyrus (pos ..."
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Cited by 15 (3 self)
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Human behavior is often dictated by rules or prescribed guides for action. Little is currently known regarding how these rules are stored in long-term memory or retrieved and implemented. Here, we examined the roles of ventrolateral prefrontal cortex (VLPFC) and posterior middle temporal gyrus (postMTG) in rule use. We tested two hypotheses: first, that knowledge about actions associated with abstract visual symbols is stored in postMTG, and second, that VLPFC is involved in the controlled retrieval of rule meanings. Subjects viewed a series of road signs during event-related fMRI data collection. Three types of signs were intermixed: highly familiar signs, novel signs whose meaning was explained to subjects prior to scanning, and novel signs whose meaning was not explained. Subjects were asked to think about the meaning of each sign as it was presented during scanning and then to give its meaning in a post-scan test. Left postMTG was more active when subjects viewed signs whose meaning they knew than signs whose meaning they did not know, consistent with a role in storing rule meanings. This region was not modulated by experience, in that it was equally engaged by newly trained and well-learned signs. In contrast, right VLPFC was more active for newly trained signs than for either well-learned or incorrect ones, consistent with a role in controlled retrieval. Left VLPFC was reliably engaged while subjects attempted to interpret the signs but did not differ according to knowledge or experience. These data implicate postMTG in rule storage and VLPFC in rule retrieval. D
Rapid formation of pragmatic rule representations in the human brain during instruction-based learning. Cereb Cortex
, 2010
"... this work. The present functional magnetic resonance imaging study investi-gated the instruction-based learning of novel arbitrary stimulus--response mappings in order to understand the brain mechanisms that enable successful behavioral rule implementation in the absence of trial-and-error learning. ..."
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Cited by 12 (2 self)
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this work. The present functional magnetic resonance imaging study investi-gated the instruction-based learning of novel arbitrary stimulus--response mappings in order to understand the brain mechanisms that enable successful behavioral rule implementation in the absence of trial-and-error learning. We developed a novel task design that allowed the examination of rapidly evolving brain activation dynamics starting from an explicit instruction phase and further across a short behavioral practice phase. As a first key result, the study revealed that different sets of brain regions displayed either decreasing or increasing activation profiles already across the first few practice trials, suggesting an impressively rapid redistribution of labor throughout the brain. Furthermore, behavioral performance improvement across practice was tightly coupled with brain activation during the practice phase (caudate nucleus), the instruction phase (lateral midprefrontal cortex), or both (lateral premotor cortex bordering prefrontal cortex). Together, the present results provide first important insights into the brain systems involved in the rapid transfer of control from initially abstract rule representations induced by explicit instructions toward pragmatic representations enabling the fluent behavioral implementation.
