For much of modern epileptology, focal epilepsy was described as a problem beginning in one abnormal area and spreading into otherwise uninvolved brain. Network neuroscience has made that picture more complex.
The focal model was clinically powerful
Jacksonian semiology, EEG localisation and successful focal surgery all supported the idea that seizures could originate in discrete cortical regions.
The concepts of seizure-onset zone and epileptogenic zone grew from this localisation tradition.
Intracranial recordings revealed complexity
Depth electrodes and SEEG showed that seizures can involve distributed regions with rapid bidirectional interactions.
Some apparently focal epilepsies were better explained by organised networks than by one autonomous point.
Imaging and computational neuroscience expand the model
Functional MRI, diffusion imaging, MEG, high-density EEG and graph-theory analysis enabled researchers to study connectivity beyond the visible lesion.
Network abnormalities were found both within and outside classical seizure-onset regions.
The network model does not mean localisation is obsolete
Surgery still depends on identifying tissue or nodes whose treatment can interrupt the epileptic system.
The practical shift is from ‘Where is the one focus?’ toward ‘Which regions are necessary for this seizure network?’
Neuromodulation makes network thinking clinically visible
DBS and RNS can reduce seizures without removing all epileptogenic tissue.
Their success reinforces the idea that modulating key network nodes can alter seizure dynamics.
Evidence remains heterogeneous
Meta-analysis shows that network abnormalities vary by method and epilepsy subtype.
Network metrics are promising but are not yet a universal clinical replacement for established presurgical methods.
Related reading
Sources and further reading
- Toward a Mechanistic Understanding of Epileptic Networks
- Defining epileptogenic networks: Contribution of SEEG and signal analysis
- Systematic review/meta-analysis of brain network organisation in focal epilepsy
Evidence checked: September 2026.