Dataset of intracranial EEG during cortical stimulation evoking visual effects

In this dataset we included iEEG recordings of responses to 115 intracranial high frequency stimulations evoking
visual hallucinations, in 22 patients undergoing stereo-EEG presurgical evaluation for drug-resistant epilepsy.

The dataset contains 21 seconds of iEEG data around each stimulation, 8 seconds before the start of the stimulation,
up to 5 seconds of intracranial stimulation and 8 seconds after the end of the stimulation.

We have used high-frequency bipolar stimulations of different areas of the brain, using alternating polarity
biphasic pulses having a duration of 1 ms, at 43.2 Hz or 50 Hz, current intensity between 0.25 to 3 mA, for up to 5 s.
Alternating polarity protocol allows disambiguating neuronal responses time-locked to the stimulation pulses
from the artefactual components, according to Barborica et al., 2022 (doi: 10.1002/hbm.25749). It is therefore
possible to identify the brain networks underlying the clinical effects, and to create symptom-related
activation/connectivity maps.

The contact pair on which stimulation is applied, the current intensity level and evoked effect are specified
in the events tsv. The responses are classified in 14 clinical categories: elementary (unstructured
flashes of light), plus hallucination (presence of light in different forms or colors overlaying the background vision),
minus hallucination (negative elementary phenomena described as scotoma, quadrantanopia, hemianopia or amaurosis),
static, dynamic, continuous hallucination, intermittent hallucination, peripheric, central,
whole visual field, color, non-color, combined visual symptoms, multimodal hallucinations.

Not all patients in which stimulations evoked visual hallucinations met the inclusion criteria for network analysis
that requires running the freesurfer pipeline, for instance patients having prior resections, therefore there are subjects
that do not contain ieeg data. However, they were kept in order to match the number of patients in the companion manuscript.

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