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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

Intracranial EEG recordings from MTLE mice.a: Experimental setup. The intracranial placement of site recordings consisted on two electrodes placed bilaterally in the cortex (LC and RC, red) and two in the hippocampus (LH and RH, green).b: EEG recording was coupled to videographic recordings for visual confirmation of the seizure events.c1-c3: Examples extracted from the EEG recordings at the day of the injection (c1), the next day (c2) and after 21 days (c3). Overall changes in the electrical potential are shown in the upper row and after filtering for low frequency (1–14 Hz) in the lower row. The red dotted line marks high statistical similarities between electrodes, which provides high values of FC. Notice that RH is the site of the KA injection, and shows a higher epileptogenic activity that can be easily detected by looking at the amplitude of the time series associated to the RH electrode.
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f1: Intracranial EEG recordings from MTLE mice.a: Experimental setup. The intracranial placement of site recordings consisted on two electrodes placed bilaterally in the cortex (LC and RC, red) and two in the hippocampus (LH and RH, green).b: EEG recording was coupled to videographic recordings for visual confirmation of the seizure events.c1-c3: Examples extracted from the EEG recordings at the day of the injection (c1), the next day (c2) and after 21 days (c3). Overall changes in the electrical potential are shown in the upper row and after filtering for low frequency (1–14 Hz) in the lower row. The red dotted line marks high statistical similarities between electrodes, which provides high values of FC. Notice that RH is the site of the KA injection, and shows a higher epileptogenic activity that can be easily detected by looking at the amplitude of the time series associated to the RH electrode.

Mentions: According toFigure 1, four electrodes were implanted bilaterally in the motor cortex and hippocampus. The four electrodes were positioned at -0.1mm AP, +1.6mm LL, - 1mm DV (left cortex); -0.1mm AP, -1.6mm LL, -1mm DV (right cortex); -1.8mm AP, +1.6mm LL, -2mm DV (left hippocampus); -1.8mm AP, -1.6mm LL, -2mm DV (right hippocampus). The reference electrode was placed at the frontal lobe at +0.1mm AP, +0.1mm LL, -0.5mm DV, and the ground electrode was positioned over the cervical paraspinous area. Hereon, we labeled these electrodes as left cortex (LC), right cortex (RC), left hippocampus (LH) and right hippocampus (RH). The KA injection was applied at the site of the RH electrode (indicated by a red arrow in panel a).


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)

Intracranial EEG recordings from MTLE mice.a: Experimental setup. The intracranial placement of site recordings consisted on two electrodes placed bilaterally in the cortex (LC and RC, red) and two in the hippocampus (LH and RH, green).b: EEG recording was coupled to videographic recordings for visual confirmation of the seizure events.c1-c3: Examples extracted from the EEG recordings at the day of the injection (c1), the next day (c2) and after 21 days (c3). Overall changes in the electrical potential are shown in the upper row and after filtering for low frequency (1–14 Hz) in the lower row. The red dotted line marks high statistical similarities between electrodes, which provides high values of FC. Notice that RH is the site of the KA injection, and shows a higher epileptogenic activity that can be easily detected by looking at the amplitude of the time series associated to the RH electrode.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f1: Intracranial EEG recordings from MTLE mice.a: Experimental setup. The intracranial placement of site recordings consisted on two electrodes placed bilaterally in the cortex (LC and RC, red) and two in the hippocampus (LH and RH, green).b: EEG recording was coupled to videographic recordings for visual confirmation of the seizure events.c1-c3: Examples extracted from the EEG recordings at the day of the injection (c1), the next day (c2) and after 21 days (c3). Overall changes in the electrical potential are shown in the upper row and after filtering for low frequency (1–14 Hz) in the lower row. The red dotted line marks high statistical similarities between electrodes, which provides high values of FC. Notice that RH is the site of the KA injection, and shows a higher epileptogenic activity that can be easily detected by looking at the amplitude of the time series associated to the RH electrode.
Mentions: According toFigure 1, four electrodes were implanted bilaterally in the motor cortex and hippocampus. The four electrodes were positioned at -0.1mm AP, +1.6mm LL, - 1mm DV (left cortex); -0.1mm AP, -1.6mm LL, -1mm DV (right cortex); -1.8mm AP, +1.6mm LL, -2mm DV (left hippocampus); -1.8mm AP, -1.6mm LL, -2mm DV (right hippocampus). The reference electrode was placed at the frontal lobe at +0.1mm AP, +0.1mm LL, -0.5mm DV, and the ground electrode was positioned over the cervical paraspinous area. Hereon, we labeled these electrodes as left cortex (LC), right cortex (RC), left hippocampus (LH) and right hippocampus (RH). The KA injection was applied at the site of the RH electrode (indicated by a red arrow in panel a).

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