Altered resting state networks in epileptic patients with generalized tonic–clonic seizures

Seizure Frequency Can Alter Brain Connectivity: Evidence from Resting-State fMRI

“…There have been few reports of increased DMN connectivity in patients with epilepsy. 6,14 Our findings of differential DMN connectivity, which was increased in the infrequent-seizure group and decreased in the frequent-seizure group, directly supports the reports by Bettus et al 2 and Greicius et al 47 of increasing DMN connectivity as a compensatory mechanism. Hence, we presume that increasing DMN connectivity is a protective response and might indicate good seizure control in patients with epilepsy.…”

“…These differences could suggest disease focus, or could be indicators of disease progression and associated compensatory mechanisms. We found that there were several areas of decreased connectivity with associated decreased connectivity of the DMN, as found by many other researchers [7][8]14,35,36 and as has been observed in children with refractory epilepsy, 24 which is known to correlate with disease duration. 6,14 Decreased connectivity was limited to the temporal lobes in patients with infrequent seizures and was widespread and involved the frontal, parietal, and temporal lobes, thalamus, and cerebellum in patients with frequent seizures.…”

“…We found that there were several areas of decreased connectivity with associated decreased connectivity of the DMN, as found by many other researchers [7][8]14,35,36 and as has been observed in children with refractory epilepsy, 24 which is known to correlate with disease duration. 6,14 Decreased connectivity was limited to the temporal lobes in patients with infrequent seizures and was widespread and involved the frontal, parietal, and temporal lobes, thalamus, and cerebellum in patients with frequent seizures. Because evidence of decreased connectivity has also been associated with several neuropsychiatric diseases such as dementia, stroke, traumatic brain injury, depression, and schizophrenia, it is possible that decreased connectivity might be indicative of the cognitive and social deficits associated with the disease together with the disease burden.…”

“…[1][2][3][4]6 Graph-theory analysis of resting-state fMRI data from patients with epilepsy also revealed decreased functional nodal topologic properties of the DMN that were positively correlated with disease duration. 8,[11][12][13][14] Regional homogeneity analysis of resting-state fMRI data was even used as a presurgical tool for seizure identification in patients with MR-negative focal epilepsy. 15 Thus, various models of data analysis have helped in understanding epilepsy further, and now there is increasing interest in using these models to reclassify epilepsy as a focal epileptogenic area 10,15 or as a network of seizure-generating areas.…”

Identifying Corticothalamic Network Epicenters in Patients with Idiopathic Generalized Epilepsy

“…The premotor cortex and specific nuclei (pulvinar and ventrolateral nucleus) showed increased FCS within the motor-thalamic but not the sensory-thalamic network. This is analogous to the disruption of functional integrity in the sensorimotor network of the neocortex 27 and may reflect the higher excitability of the motor system of patients with IGE compared with controls. 28 Thus, the motor system of these patients may be more susceptible to behavioral symptoms driven by the SMA during cognitive tasks.…”