Neuroscience
The following paper is available as an open full-download from PLoS. It provides an interesting example of the use of stop-signal tasks in pursuing a better understanding of executive functioning and its neuroanatomical correlates:
Full publication
Rule-guided executive control of response inhibition: functional topography of the inferior frontal cortex.
PLoS One. 2011;6(6):e20840
Cai W, Leung HC
Abstract
BACKGROUND: The human inferior frontal cortex (IFC) is a large heterogeneous structure with distinct cytoarchitectonic subdivisions and fiber connections. It has been found involved in a wide range of executive control processes from target detection, rule retrieval to response control. Since these processes are often being studied separately, the functional organization of executive control processes within the IFC remains unclear.
METHODOLOGY/PRINCIPAL FINDINGS: We conducted an fMRI study to examine the activities of the subdivisions of IFC during the presentation of a task cue (rule retrieval) and during the performance of a stop-signal task (requiring response generation and inhibition) in comparison to a not-stop task (requiring response generation but not inhibition). We utilized a mixed event-related and block design to separate brain activity in correspondence to transient control processes from rule-related and sustained control processes. We found differentiation in control processes within the IFC. Our findings reveal that the bilateral ventral-posterior IFC/anterior insula are more active on both successful and unsuccessful stop trials relative to not-stop trials, suggesting their potential role in the early stage of stopping such as triggering the stop process. Direct countermanding seems to be outside of the IFC. In contrast, the dorsal-posterior IFC/inferior frontal junction (IFJ) showed transient activity in correspondence to the infrequent presentation of the stop signal in both tasks and the left anterior IFC showed differential activity in response to the task cues. The IFC subdivisions also exhibited similar but distinct patterns of functional connectivity during response control.
CONCLUSIONS/SIGNIFICANCE: Our findings suggest that executive control processes are distributed across the IFC and that the different subdivisions of IFC may support different control operations through parallel cortico-cortical and cortico-striatal circuits.
PMID: 21673969 [PubMed - indexed for MEDLINE]
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Neuroscience
Stop-Signal Task
The following paper is available as an open full-download from PLoS. It provides an interesting example of the use of stop-signal tasks in pursuing a better understanding of executive functioning and its neuroanatomical correlates:
Full publication
Rule-guided executive control of response inhibition: functional topography of the inferior frontal cortex.
PLoS One. 2011;6(6):e20840
Cai W, Leung HC
Abstract
BACKGROUND: The human inferior frontal cortex (IFC) is a large heterogeneous structure with distinct cytoarchitectonic subdivisions and fiber connections. It has been found involved in a wide range of executive control processes from target detection, rule retrieval to response control. Since these processes are often being studied separately, the functional organization of executive control processes within the IFC remains unclear.
METHODOLOGY/PRINCIPAL FINDINGS: We conducted an fMRI study to examine the activities of the subdivisions of IFC during the presentation of a task cue (rule retrieval) and during the performance of a stop-signal task (requiring response generation and inhibition) in comparison to a not-stop task (requiring response generation but not inhibition). We utilized a mixed event-related and block design to separate brain activity in correspondence to transient control processes from rule-related and sustained control processes. We found differentiation in control processes within the IFC. Our findings reveal that the bilateral ventral-posterior IFC/anterior insula are more active on both successful and unsuccessful stop trials relative to not-stop trials, suggesting their potential role in the early stage of stopping such as triggering the stop process. Direct countermanding seems to be outside of the IFC. In contrast, the dorsal-posterior IFC/inferior frontal junction (IFJ) showed transient activity in correspondence to the infrequent presentation of the stop signal in both tasks and the left anterior IFC showed differential activity in response to the task cues. The IFC subdivisions also exhibited similar but distinct patterns of functional connectivity during response control.
CONCLUSIONS/SIGNIFICANCE: Our findings suggest that executive control processes are distributed across the IFC and that the different subdivisions of IFC may support different control operations through parallel cortico-cortical and cortico-striatal circuits.
PMID: 21673969 [PubMed - indexed for MEDLINE]
- Talk To The Hand And Just Say No
A new fMRI paper (Grosbras et al., 2007) examined the hemodynamic response [an indirect reflection of neural activity] in 10 yr old children who were watching videos of angry faces and gestures (versus neutral faces and gestures and control stimuli,...
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A new article in PNAS identified two distinct task-control networks by "applying graph theory to resting state functional connectivity MRI data" (Dosenbach et al., 2007). A press release from Washington University in St. Louis includes this quote from...
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Space Fortress game training and executive control in older adults: A pilot intervention Neuropsychol Dev Cogn B Aging Neuropsychol Cogn. 2011 Oct 12; Stern Y, Blumen HM, Rich LW, Richards A, Herzberg G, Gopher D Abstract ABSTRACT We investigated the...
- Neuropsychology Abstract Of The Day: Mild Cognitive Impairment (mci) And Neuropsychological Testing
Belleville S, Chertkow H, & Gauthier S. Working memory and control of attention in persons with Alzheimer's disease and mild cognitive impairment. Neuropsychology. 2007 Jul; 21(4): 458-469. Research CenterInstitut Universitaire de Geriatrie de Montreal,...
- Abstract Of The Day: Frontal Lobe Functioning
Ardesheer Talati and Joy Hirsch. Functional Specialization within the Medial Frontal Gyrus for Perceptual Go/No-Go Decisions Based on "What," "When," and "Where" Related Information: An fMRI Study. Journal of Cognitive Neuroscience. 2005; 17: 981-993....