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Deactivation of the default mode network as a marker of impaired consciousness: an fMRI study.

Crone JS, Ladurner G, Höller Y, Golaszewski S, Trinka E, Kronbichler M - PLoS ONE (2011)

Bottom Line: Results show that deactivation in medial regions is reduced in MCS and absent in UWS patients compared to healthy controls.Interestingly, all patients who deactivated during speech processing (except for one) showed activation in left frontal regions which are associated with conscious processing.Our results indicate that deactivation of the DMN can be associated with the level of consciousness by selecting those who are able to interrupt ongoing introspective processes.

View Article: PubMed Central - PubMed

Affiliation: Neuroscience Institute and Centre for Neurocognitive Research, Christian-Doppler-Clinic, Paracelsus Private Medical University, Salzburg, Austria. j.crone@neurocognition.org

ABSTRACT
Diagnosis of patients with a disorder of consciousness is very challenging. Previous studies investigating resting state networks demonstrate that 2 main features of the so-called default mode network (DMN), metabolism and functional connectivity, are impaired in patients with a disorder of consciousness. However, task-induced deactivation--a third main feature of the DMN--has not been explored in a group of patients. Deactivation of the DMN is supposed to reflect interruptions of introspective processes. Seventeen patients with unresponsive wakefulness syndrome (UWS, former vegetative state), 8 patients in minimally conscious state (MCS), and 25 healthy controls were investigated with functional magnetic resonance imaging during a passive sentence listening task. Results show that deactivation in medial regions is reduced in MCS and absent in UWS patients compared to healthy controls. Moreover, behavioral scores assessing the level of consciousness correlate with deactivation in patients. On single-subject level, all control subjects but only 2 patients in MCS and 6 with UWS exposed deactivation. Interestingly, all patients who deactivated during speech processing (except for one) showed activation in left frontal regions which are associated with conscious processing. Our results indicate that deactivation of the DMN can be associated with the level of consciousness by selecting those who are able to interrupt ongoing introspective processes. In consequence, deactivation of the DMN may function as a marker of consciousness.

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Related in: MedlinePlus

Deactivation of the DMN in the control group during sentence processing.Images display BOLD signal changes overlaid on a canonical template and transformed into standard MNI space. For display purposes, results are thresholded at p<0.001, uncorrected.
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pone-0026373-g001: Deactivation of the DMN in the control group during sentence processing.Images display BOLD signal changes overlaid on a canonical template and transformed into standard MNI space. For display purposes, results are thresholded at p<0.001, uncorrected.

Mentions: The control group showed wide-spread deactivation in medial parietal regions, t(23) = 7.43, p = 0.005, and medial frontal regions, t(23) = 7.16, p<0.009, all corrected for family-wise error (FWE). Deactivation in the rMTG and lMTG were not significant for multiple corrections. Results are displayed in Figure 1. The MCS and the UWS group, in contrast, failed to show a significant deactivation effect. The MCS group showed deactivation only when lowering the threshold to p = 0.01, uncorrected. The UWS group, in contrary, showed no deactivation at all.


Deactivation of the default mode network as a marker of impaired consciousness: an fMRI study.

Crone JS, Ladurner G, Höller Y, Golaszewski S, Trinka E, Kronbichler M - PLoS ONE (2011)

Deactivation of the DMN in the control group during sentence processing.Images display BOLD signal changes overlaid on a canonical template and transformed into standard MNI space. For display purposes, results are thresholded at p<0.001, uncorrected.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3198462&req=5

pone-0026373-g001: Deactivation of the DMN in the control group during sentence processing.Images display BOLD signal changes overlaid on a canonical template and transformed into standard MNI space. For display purposes, results are thresholded at p<0.001, uncorrected.
Mentions: The control group showed wide-spread deactivation in medial parietal regions, t(23) = 7.43, p = 0.005, and medial frontal regions, t(23) = 7.16, p<0.009, all corrected for family-wise error (FWE). Deactivation in the rMTG and lMTG were not significant for multiple corrections. Results are displayed in Figure 1. The MCS and the UWS group, in contrast, failed to show a significant deactivation effect. The MCS group showed deactivation only when lowering the threshold to p = 0.01, uncorrected. The UWS group, in contrary, showed no deactivation at all.

Bottom Line: Results show that deactivation in medial regions is reduced in MCS and absent in UWS patients compared to healthy controls.Interestingly, all patients who deactivated during speech processing (except for one) showed activation in left frontal regions which are associated with conscious processing.Our results indicate that deactivation of the DMN can be associated with the level of consciousness by selecting those who are able to interrupt ongoing introspective processes.

View Article: PubMed Central - PubMed

Affiliation: Neuroscience Institute and Centre for Neurocognitive Research, Christian-Doppler-Clinic, Paracelsus Private Medical University, Salzburg, Austria. j.crone@neurocognition.org

ABSTRACT
Diagnosis of patients with a disorder of consciousness is very challenging. Previous studies investigating resting state networks demonstrate that 2 main features of the so-called default mode network (DMN), metabolism and functional connectivity, are impaired in patients with a disorder of consciousness. However, task-induced deactivation--a third main feature of the DMN--has not been explored in a group of patients. Deactivation of the DMN is supposed to reflect interruptions of introspective processes. Seventeen patients with unresponsive wakefulness syndrome (UWS, former vegetative state), 8 patients in minimally conscious state (MCS), and 25 healthy controls were investigated with functional magnetic resonance imaging during a passive sentence listening task. Results show that deactivation in medial regions is reduced in MCS and absent in UWS patients compared to healthy controls. Moreover, behavioral scores assessing the level of consciousness correlate with deactivation in patients. On single-subject level, all control subjects but only 2 patients in MCS and 6 with UWS exposed deactivation. Interestingly, all patients who deactivated during speech processing (except for one) showed activation in left frontal regions which are associated with conscious processing. Our results indicate that deactivation of the DMN can be associated with the level of consciousness by selecting those who are able to interrupt ongoing introspective processes. In consequence, deactivation of the DMN may function as a marker of consciousness.

Show MeSH
Related in: MedlinePlus