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🔌Intracranial EEG

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

Also called: iEEG · ECoG · stereo-EEG

OverviewOverviewAnatomyFunctionClinicalMethodsPeopleFrontiers
14 min read Frequently asked questions

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

Intracranial EEG
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Quick facts

invasive signalsFocus
82/100Research
45/100Awareness
85/100Complexity
75/100Clinical
60/100Debate

Intracranial EEG records electrical activity from electrodes on the cortical surface (ECoG) or in depth (stereo-EEG / SEEG). It offers millimetre spatial scale and kilohertz temporal bandwidth unavailable to scalp EEG or fMRI.

Clinically it maps seizure onset and eloquent cortex before epilepsy surgery; scientifically it reveals high-gamma activity tied to cognition. Coverage is sparse and ethical constraints are strict — not a general “brain reading” tool.

Educational neuroscience context only — not medical advice. Intracranial EEG is performed in specialised clinical settings for indicated patients.

The profile

824585754060
  • Research82
  • Awareness45
  • Complexity85
  • Clinical weight75
  • Plasticity40
  • Live debate60

Seven ways into this topic

01

Overview

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

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 02

Anatomy

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

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 03

Function

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

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 04

Clinical

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

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 05

Methods

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

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 06

People

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

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 07

Frontiers

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

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Frequently asked questions

How is iEEG different from scalp EEG?
iEEG sits under the skull, nearer generators, with far less spatial smearing and access to high-frequency (high-gamma) bands that scalp signals rarely resolve cleanly.
What is high-gamma activity?
Broadband power increases roughly ~70–150+ Hz that often track local neuronal population activity during perception, language and movement tasks.
Who receives intracranial EEG?
Typically patients with drug-resistant epilepsy being evaluated for resective or neuromodulation surgery — not healthy volunteers.
ECoG versus stereo-EEG?
ECoG grids/strips sample cortical surface widely; SEEG depth electrodes sample networks in 3D through smaller openings with different risk profiles.
Can iEEG read thoughts?
No. It records local field dynamics linked to tasks; decoding is limited, supervised and far from mind-reading sci-fi.
What are the main risks?
Infection, haemorrhage, neurological deficit and seizures — managed in specialised centres with informed consent.
Why do cognitive scientists value iEEG?
It uniquely combines human cognitive tasks with high spatiotemporal resolution near the generators — a rare window when clinical care already requires electrodes.
Does sparse sampling bias findings?
Yes. Electrodes cover only planned clinical targets; absence of signal elsewhere is not proof of non-involvement.

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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