Limits...
Relationship between the anterior forebrain mesocircuit and the default mode network in the structural bases of disorders of consciousness.

Lant ND, Gonzalez-Lara LE, Owen AM, Fernández-Espejo D - Neuroimage Clin (2015)

Bottom Line: We found evidence of significant damage to subcortico-cortical and cortico-cortical fibers, which were more severe in vegetative state patients and correlated with clinical severity as determined by Coma Recovery Scale-Revised (CRS-R) scores.Lastly, we found significant damage in all fiber tracts connecting the precuneus with cortical and subcortical areas.Our results suggest a strong relationship between the default mode network - and most importantly the precuneus - and the anterior forebrain mesocircuit in the neural basis of the DOC.

View Article: PubMed Central - PubMed

Affiliation: The Brain and Mind Institute, The University of Western Ontario, London, ON N6A 5B7, Canada.

ABSTRACT
The specific neural bases of disorders of consciousness (DOC) are still not well understood. Some studies have suggested that functional and structural impairments in the default mode network may play a role in explaining these disorders. In contrast, others have proposed that dysfunctions in the anterior forebrain mesocircuit involving striatum, globus pallidus, and thalamus may be the main underlying mechanism. Here, we provide the first report of structural integrity of fiber tracts connecting the nodes of the mesocircuit and the default mode network in 8 patients with DOC. We found evidence of significant damage to subcortico-cortical and cortico-cortical fibers, which were more severe in vegetative state patients and correlated with clinical severity as determined by Coma Recovery Scale-Revised (CRS-R) scores. In contrast, fiber tracts interconnecting subcortical nodes were not significantly impaired. Lastly, we found significant damage in all fiber tracts connecting the precuneus with cortical and subcortical areas. Our results suggest a strong relationship between the default mode network - and most importantly the precuneus - and the anterior forebrain mesocircuit in the neural basis of the DOC.

No MeSH data available.


Related in: MedlinePlus

Fractional anisotropy of composite fiber tracts in DOC patients and healthy controls. Middle line is median, lower box bound first quartile, upper box bound third quartile, whiskers 95% C.I., open circles outliers from C.I. Group main effect *p < 0.05, **p < 0.01. Sub: subcortical, Cor: cortical.
© Copyright Policy - CC BY-NC-ND
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4660379&req=5

f0010: Fractional anisotropy of composite fiber tracts in DOC patients and healthy controls. Middle line is median, lower box bound first quartile, upper box bound third quartile, whiskers 95% C.I., open circles outliers from C.I. Group main effect *p < 0.05, **p < 0.01. Sub: subcortical, Cor: cortical.

Mentions: One-way ANOVA revealed significant differences in global white matter FA between DOC patients and healthy controls (F1,14 = 4.662, p = 0.049). This variable also correlated with our dependent variables (individual pathways FA) so it was included as a covariate in the analysis of the individual pathways in order to control for the effect of widespread (i.e. nonspecific) white matter damage. Repeated measures ANCOVA on the lateralized composite fiber tracts revealed no significant effect of hemisphere on cortico-cortical fiber tract FA values. DOC patients had significantly lower FA values in these tracts (Fig. 2) (F1,13 = 23.053, p < 0.001), as well as midline cortico-cortical fiber tracts (i.e. PCu–FMC; F1,11 = 21.155, p < 0.001) as compared to controls. There was a significant effect of hemisphere on subcortico-subcortical and subcortico-cortical fiber tract FA values and therefore the left and right tracts were analyzed individually. Patients had significantly lower FA values in the left (F1,13 = 11.594, p < 0.01) and right (F1,13 = 7.784, p < 0.05) subcortico-cortical fiber tracts. In contrast, there was no significant effect of group on subcortico-subcortical fiber tract FA values. There was no significant group by hemisphere interaction in any fiber tracts.


Relationship between the anterior forebrain mesocircuit and the default mode network in the structural bases of disorders of consciousness.

Lant ND, Gonzalez-Lara LE, Owen AM, Fernández-Espejo D - Neuroimage Clin (2015)

Fractional anisotropy of composite fiber tracts in DOC patients and healthy controls. Middle line is median, lower box bound first quartile, upper box bound third quartile, whiskers 95% C.I., open circles outliers from C.I. Group main effect *p < 0.05, **p < 0.01. Sub: subcortical, Cor: cortical.
© Copyright Policy - CC BY-NC-ND
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4660379&req=5

f0010: Fractional anisotropy of composite fiber tracts in DOC patients and healthy controls. Middle line is median, lower box bound first quartile, upper box bound third quartile, whiskers 95% C.I., open circles outliers from C.I. Group main effect *p < 0.05, **p < 0.01. Sub: subcortical, Cor: cortical.
Mentions: One-way ANOVA revealed significant differences in global white matter FA between DOC patients and healthy controls (F1,14 = 4.662, p = 0.049). This variable also correlated with our dependent variables (individual pathways FA) so it was included as a covariate in the analysis of the individual pathways in order to control for the effect of widespread (i.e. nonspecific) white matter damage. Repeated measures ANCOVA on the lateralized composite fiber tracts revealed no significant effect of hemisphere on cortico-cortical fiber tract FA values. DOC patients had significantly lower FA values in these tracts (Fig. 2) (F1,13 = 23.053, p < 0.001), as well as midline cortico-cortical fiber tracts (i.e. PCu–FMC; F1,11 = 21.155, p < 0.001) as compared to controls. There was a significant effect of hemisphere on subcortico-subcortical and subcortico-cortical fiber tract FA values and therefore the left and right tracts were analyzed individually. Patients had significantly lower FA values in the left (F1,13 = 11.594, p < 0.01) and right (F1,13 = 7.784, p < 0.05) subcortico-cortical fiber tracts. In contrast, there was no significant effect of group on subcortico-subcortical fiber tract FA values. There was no significant group by hemisphere interaction in any fiber tracts.

Bottom Line: We found evidence of significant damage to subcortico-cortical and cortico-cortical fibers, which were more severe in vegetative state patients and correlated with clinical severity as determined by Coma Recovery Scale-Revised (CRS-R) scores.Lastly, we found significant damage in all fiber tracts connecting the precuneus with cortical and subcortical areas.Our results suggest a strong relationship between the default mode network - and most importantly the precuneus - and the anterior forebrain mesocircuit in the neural basis of the DOC.

View Article: PubMed Central - PubMed

Affiliation: The Brain and Mind Institute, The University of Western Ontario, London, ON N6A 5B7, Canada.

ABSTRACT
The specific neural bases of disorders of consciousness (DOC) are still not well understood. Some studies have suggested that functional and structural impairments in the default mode network may play a role in explaining these disorders. In contrast, others have proposed that dysfunctions in the anterior forebrain mesocircuit involving striatum, globus pallidus, and thalamus may be the main underlying mechanism. Here, we provide the first report of structural integrity of fiber tracts connecting the nodes of the mesocircuit and the default mode network in 8 patients with DOC. We found evidence of significant damage to subcortico-cortical and cortico-cortical fibers, which were more severe in vegetative state patients and correlated with clinical severity as determined by Coma Recovery Scale-Revised (CRS-R) scores. In contrast, fiber tracts interconnecting subcortical nodes were not significantly impaired. Lastly, we found significant damage in all fiber tracts connecting the precuneus with cortical and subcortical areas. Our results suggest a strong relationship between the default mode network - and most importantly the precuneus - and the anterior forebrain mesocircuit in the neural basis of the DOC.

No MeSH data available.


Related in: MedlinePlus