Limits...
Dissociated multimodal hubs and seizures in temporal lobe epilepsy.

Douw L, DeSalvo MN, Tanaka N, Cole AJ, Liu H, Reinsberger C, Stufflebeam SM - Ann Clin Transl Neurol (2015)

Bottom Line: In TLE patients, there was lower overall functional integrity of the DMN as well as an increase in posterior hub connections with other modules.Anatomical between-module connectivity was globally decreased.We provide evidence for dissociated anatomical and functional hub connectivity in TLE.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital Charlestown, Massachusetts ; Department of Radiology, Harvard Medical School Boston, Massachusetts ; Department of Anatomy and Neurosciences, VU University Medical Center Amsterdam, The Netherlands.

ABSTRACT

Objective: Brain connectivity at rest is altered in temporal lobe epilepsy (TLE), particularly in "hub" areas such as the posterior default mode network (DMN). Although both functional and anatomical connectivity are disturbed in TLE, the relationships between measures as well as to seizure frequency remain unclear. We aim to clarify these associations using connectivity measures specifically sensitive to hubs.

Methods: Connectivity between 1000 cortical surface parcels was determined in 49 TLE patients and 23 controls with diffusion and resting-state functional magnetic resonance imaging. Two types of hub connectivity were investigated across multiple brain modules (the DMN, motor system, etcetera): (1) within-module connectivity (a measure of local importance that assesses a parcel's communication level within its own subnetwork) and (2) between-module connectivity (a measure that assesses connections across multiple modules).

Results: In TLE patients, there was lower overall functional integrity of the DMN as well as an increase in posterior hub connections with other modules. Anatomical between-module connectivity was globally decreased. Higher DMN disintegration (DD) coincided with higher anatomical between-module connectivity, whereas both were associated with increased seizure frequency. DD related to seizure frequency through mediating effects of anatomical connectivity, but seizure frequency also correlated with anatomical connectivity through DD, indicating a complex interaction between multimodal networks and symptoms.

Interpretation: We provide evidence for dissociated anatomical and functional hub connectivity in TLE. Moreover, shifts in functional hub connections from within to outside the DMN, an overall loss of integrative anatomical communication, and the interaction between the two increase seizure frequency.

No MeSH data available.


Related in: MedlinePlus

Mediation analyses of the associations between functional default mode network (DMN+) shift, anatomical between-module connectivity loss, and monthly seizure frequency. *P < 0.05, **P < 0.01. Numbers next to arrows are normalized coefficients in regression models, with the normalized coefficients when taking the mediator into account in parentheses.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4402080&req=5

fig06: Mediation analyses of the associations between functional default mode network (DMN+) shift, anatomical between-module connectivity loss, and monthly seizure frequency. *P < 0.05, **P < 0.01. Numbers next to arrows are normalized coefficients in regression models, with the normalized coefficients when taking the mediator into account in parentheses.

Mentions: We then tested whether global anatomical between-module connectivity mediated the association between functional DD and seizure frequency. The association between DD and higher seizure frequency proved to be mediated by higher anatomical between-module connectivity (Fig.6; 95% CI 2.723 to 25.092). Additionally, a mediation model with higher seizure frequency relating to increasing anatomical modular connectivity through higher DD also yielded significant results (Fig.6; 95% CI 0.0001 to 0.0011).


Dissociated multimodal hubs and seizures in temporal lobe epilepsy.

Douw L, DeSalvo MN, Tanaka N, Cole AJ, Liu H, Reinsberger C, Stufflebeam SM - Ann Clin Transl Neurol (2015)

Mediation analyses of the associations between functional default mode network (DMN+) shift, anatomical between-module connectivity loss, and monthly seizure frequency. *P < 0.05, **P < 0.01. Numbers next to arrows are normalized coefficients in regression models, with the normalized coefficients when taking the mediator into account in parentheses.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4402080&req=5

fig06: Mediation analyses of the associations between functional default mode network (DMN+) shift, anatomical between-module connectivity loss, and monthly seizure frequency. *P < 0.05, **P < 0.01. Numbers next to arrows are normalized coefficients in regression models, with the normalized coefficients when taking the mediator into account in parentheses.
Mentions: We then tested whether global anatomical between-module connectivity mediated the association between functional DD and seizure frequency. The association between DD and higher seizure frequency proved to be mediated by higher anatomical between-module connectivity (Fig.6; 95% CI 2.723 to 25.092). Additionally, a mediation model with higher seizure frequency relating to increasing anatomical modular connectivity through higher DD also yielded significant results (Fig.6; 95% CI 0.0001 to 0.0011).

Bottom Line: In TLE patients, there was lower overall functional integrity of the DMN as well as an increase in posterior hub connections with other modules.Anatomical between-module connectivity was globally decreased.We provide evidence for dissociated anatomical and functional hub connectivity in TLE.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital Charlestown, Massachusetts ; Department of Radiology, Harvard Medical School Boston, Massachusetts ; Department of Anatomy and Neurosciences, VU University Medical Center Amsterdam, The Netherlands.

ABSTRACT

Objective: Brain connectivity at rest is altered in temporal lobe epilepsy (TLE), particularly in "hub" areas such as the posterior default mode network (DMN). Although both functional and anatomical connectivity are disturbed in TLE, the relationships between measures as well as to seizure frequency remain unclear. We aim to clarify these associations using connectivity measures specifically sensitive to hubs.

Methods: Connectivity between 1000 cortical surface parcels was determined in 49 TLE patients and 23 controls with diffusion and resting-state functional magnetic resonance imaging. Two types of hub connectivity were investigated across multiple brain modules (the DMN, motor system, etcetera): (1) within-module connectivity (a measure of local importance that assesses a parcel's communication level within its own subnetwork) and (2) between-module connectivity (a measure that assesses connections across multiple modules).

Results: In TLE patients, there was lower overall functional integrity of the DMN as well as an increase in posterior hub connections with other modules. Anatomical between-module connectivity was globally decreased. Higher DMN disintegration (DD) coincided with higher anatomical between-module connectivity, whereas both were associated with increased seizure frequency. DD related to seizure frequency through mediating effects of anatomical connectivity, but seizure frequency also correlated with anatomical connectivity through DD, indicating a complex interaction between multimodal networks and symptoms.

Interpretation: We provide evidence for dissociated anatomical and functional hub connectivity in TLE. Moreover, shifts in functional hub connections from within to outside the DMN, an overall loss of integrative anatomical communication, and the interaction between the two increase seizure frequency.

No MeSH data available.


Related in: MedlinePlus