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Intracranial EEG · Electrocorticography and depth electrodes — millimetre-scale human recordings that reveal high-frequency dynamics surgery can see.

Reviewed 2026-08·Sources & research·Methodology·Media credits

At a glance
Score intensity

Darker cells mean a higher score for this topic on that metric.

Last reviewed Sources & creditsMedia creditsMethodology

Quick answers

What is intracranial EEG iEEG/ECoG?

Electrodes on or in the brain during clinical mapping — millimetre-scale timing that scalp EEG blurs. Teaching description of published methods.

When did Penfield-era cortical stimulation map speech?

Mid-20th-century Montreal work made awake mapping famous. Modern grids and stereo-EEG continue the classroom story without copying an OR checklist.

Is this a guide to implant surgery or dosing?

No. Educational methods atlas. Not a diagnosis, implant protocol, or medication dose.

What can iEEG resolve that scalp methods smear?

When and where populations engage during perception, speech, memory or movement — at scales scalp EEG averages away.

Research score 82 — a clinic ranking?

No. Editorial 0-100 in this methods field. Compare with EEG, fMRI and MEG neighbours.

Why do overview pages get clicks?

They name ECoG sites and cortical surface mapping early. Keep reading Overview, Anatomy, Function; do not self-schedule a procedure.

Start with this section - Function

Functionally, iEEG resolves when and where populations engage during perception, speech, memory and movement — at scales scalp methods blur.

Network percentages below are editorial teaching emphasis for typical research foci, not universal coverage statistics.

Processes

Seizure onset localisation

Identify regions that start clinical seizures.

Eloquent cortex mapping

Protect language and motor areas before resection.

High-gamma task tracking

Index local engagement during cognitive events.

Oscillatory coupling analysis

Phase–amplitude and coherence across sites.

Closed-loop stimulation research

Trigger pulses from detected states — experimental/clinical.

Decoding for BCI research

Limited, supervised intention decoding near motor sites.

Networks

Sensorimotor high-gamma
92
Language cortex dynamics
78
Medial temporal memory
70
Frontoparietal task control
55
Default / unsampled cortex
30

Sensorimotor high-gamma

Movement and somatotopic mapping staple.

Language cortex dynamics

Speech perception and production mapping.

Medial temporal memory

Encoding/retrieval on hippocampal depth leads.

Frontoparietal task control

Sampled when grids/depths reach control hubs.

Default / unsampled cortex

Large territories often lack electrodes entirely.

Examples

Finger-tapping high-gamma map

Localise hand motor cortex before resection.

Auditory sentence listening

STG electrodes track speech envelope and phonemes.

Memory encoding in MTL

Depth contacts show item-related high-frequency bursts.

Seizure onset pattern reading

Clinical teams identify ictal onset zones.

Compare with EEG, MEG and fMRI method pages for complementary trade-offs.

Sources & research

  1. Promises and limitations of human intracranial electroencephalographyParvizi J; Kastner S · 2018 · Nature NeurosciencePromises and limits of human iEEG.DOI
  2. High-frequency neural activity and human cognition: past, present and possible future of intracranial EEG researchLachaux JP; et al. · 2012 · Progress in NeurobiologyHigh-frequency activity and cognition review.DOI
  3. High-frequency gamma oscillations and human brain mapping with electrocorticographyCrone NE; et al. · 2006 · Progress in Brain ResearchHigh-gamma mapping with ECoG.DOI

Media credits

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