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Longitudinal variations of brain functional connectivity: A case report study based on a mouse model of epilepsy.

Erramuzpe A, Encinas JM, Sierra A, Maletic-Savatic M, Brewster AL, Anderson AE, Stramaglia S, Cortes JM - F1000Res (2015)

Bottom Line: Our hypothesis is that FC can differentiate global brain interactions across a time-scale of days.We found that the overall network FC at low frequency bands decreased immediately after status epilepticus was provoked, and increased monotonously later on during the latent period.Overall, our results demonstrate the capacity  of FC to address longitudinal variations of brain connectivity across the establishment of pathological states.

View Article: PubMed Central - PubMed

Affiliation: Biocruces Health Research Institute, Cruces University Hospital, Barakaldo, 48903, Spain.

ABSTRACT
Brain Functional Connectivity (FC) quantifies statistical dependencies between areas of the brain. FC has been widely used to address altered function of brain circuits in control conditions compared to different pathological states, including epilepsy, a major neurological disorder. However, FC also has the as yet unexplored potential to help us understand the pathological transformation of the brain circuitry. Our hypothesis is that FC can differentiate global brain interactions across a time-scale of days. To this end, we present a case report study based on a mouse model for epilepsy and analyze longitudinal intracranial electroencephalography data of epilepsy to calculate FC across three stages:   1, the initial insult (status epilepticus); 2, the latent period, when epileptogenic networks emerge; and 3, chronic epilepsy, when unprovoked seizures occur as spontaneous events. We found that the overall network FC at low frequency bands decreased immediately after status epilepticus was provoked, and increased monotonously later on during the latent period. Overall, our results demonstrate the capacity  of FC to address longitudinal variations of brain connectivity across the establishment of pathological states.

No MeSH data available.


Related in: MedlinePlus

Longitudinal variations of FC across different days and different frequency bands.a,b: C and PC matrices across different days post KA injection and different frequency bands: low freq (1–14 Hz) and high freq (25–70 Hz).c,d: For the matrices plotted in panels a and b, we calculated the network connectivity index (for definition see methods) and represented across different days and frequency bands. Asterisks mean, for each condition respect to dpi0 (control), statistical significance differences with pvalue smaller than 0.05. C (and to a smaller extent PC) clearly differentiate brain states across days in the lower frequency band (blue line), showing a strong decrement at dpi1 and afterwards, FC started to increase until dpi21.
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f2: Longitudinal variations of FC across different days and different frequency bands.a,b: C and PC matrices across different days post KA injection and different frequency bands: low freq (1–14 Hz) and high freq (25–70 Hz).c,d: For the matrices plotted in panels a and b, we calculated the network connectivity index (for definition see methods) and represented across different days and frequency bands. Asterisks mean, for each condition respect to dpi0 (control), statistical significance differences with pvalue smaller than 0.05. C (and to a smaller extent PC) clearly differentiate brain states across days in the lower frequency band (blue line), showing a strong decrement at dpi1 and afterwards, FC started to increase until dpi21.

Mentions: Motivated by a previous study of synchronization clusters in human temporal lobe epilepsy14, we introduced a network synchronization index that we named the Network Connectivity Index (NCI), which accounted for all electrode interactions, c.f.,Figures 2c,d. To calculate NCI, we summed all the absolute values of all matrix elements in either C or PC divided byN(N - 1), a normalization factor equal to the total number of pairs contained in the sum minus the principal diagonal elements; thus, the NCI ignores all diagonal elements Cii and PCii, as they are equal to 1 in both C and PC matrices.


Longitudinal variations of brain functional connectivity: A case report study based on a mouse model of epilepsy.

Erramuzpe A, Encinas JM, Sierra A, Maletic-Savatic M, Brewster AL, Anderson AE, Stramaglia S, Cortes JM - F1000Res (2015)

Longitudinal variations of FC across different days and different frequency bands.a,b: C and PC matrices across different days post KA injection and different frequency bands: low freq (1–14 Hz) and high freq (25–70 Hz).c,d: For the matrices plotted in panels a and b, we calculated the network connectivity index (for definition see methods) and represented across different days and frequency bands. Asterisks mean, for each condition respect to dpi0 (control), statistical significance differences with pvalue smaller than 0.05. C (and to a smaller extent PC) clearly differentiate brain states across days in the lower frequency band (blue line), showing a strong decrement at dpi1 and afterwards, FC started to increase until dpi21.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4482210&req=5

f2: Longitudinal variations of FC across different days and different frequency bands.a,b: C and PC matrices across different days post KA injection and different frequency bands: low freq (1–14 Hz) and high freq (25–70 Hz).c,d: For the matrices plotted in panels a and b, we calculated the network connectivity index (for definition see methods) and represented across different days and frequency bands. Asterisks mean, for each condition respect to dpi0 (control), statistical significance differences with pvalue smaller than 0.05. C (and to a smaller extent PC) clearly differentiate brain states across days in the lower frequency band (blue line), showing a strong decrement at dpi1 and afterwards, FC started to increase until dpi21.
Mentions: Motivated by a previous study of synchronization clusters in human temporal lobe epilepsy14, we introduced a network synchronization index that we named the Network Connectivity Index (NCI), which accounted for all electrode interactions, c.f.,Figures 2c,d. To calculate NCI, we summed all the absolute values of all matrix elements in either C or PC divided byN(N - 1), a normalization factor equal to the total number of pairs contained in the sum minus the principal diagonal elements; thus, the NCI ignores all diagonal elements Cii and PCii, as they are equal to 1 in both C and PC matrices.

Bottom Line: Our hypothesis is that FC can differentiate global brain interactions across a time-scale of days.We found that the overall network FC at low frequency bands decreased immediately after status epilepticus was provoked, and increased monotonously later on during the latent period.Overall, our results demonstrate the capacity  of FC to address longitudinal variations of brain connectivity across the establishment of pathological states.

View Article: PubMed Central - PubMed

Affiliation: Biocruces Health Research Institute, Cruces University Hospital, Barakaldo, 48903, Spain.

ABSTRACT
Brain Functional Connectivity (FC) quantifies statistical dependencies between areas of the brain. FC has been widely used to address altered function of brain circuits in control conditions compared to different pathological states, including epilepsy, a major neurological disorder. However, FC also has the as yet unexplored potential to help us understand the pathological transformation of the brain circuitry. Our hypothesis is that FC can differentiate global brain interactions across a time-scale of days. To this end, we present a case report study based on a mouse model for epilepsy and analyze longitudinal intracranial electroencephalography data of epilepsy to calculate FC across three stages:   1, the initial insult (status epilepticus); 2, the latent period, when epileptogenic networks emerge; and 3, chronic epilepsy, when unprovoked seizures occur as spontaneous events. We found that the overall network FC at low frequency bands decreased immediately after status epilepticus was provoked, and increased monotonously later on during the latent period. Overall, our results demonstrate the capacity  of FC to address longitudinal variations of brain connectivity across the establishment of pathological states.

No MeSH data available.


Related in: MedlinePlus