Related Experiment Video
Updated: Jul 31, 2026
09:36
Extracting Visual Evoked Potentials from EEG Data Recorded During fMRI-guided Transcranial Magnetic Stimulation
Published on: May 12, 2014
13.9K
Electrophysiological Signatures of Visual Sensations Elicited by Direct Electrical Stimulation
Yan-Yan Li1,2, Bo Zhang3, Jing Wang4
1State Key Laboratory of Cognitive Science and Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing, 100101, China.
Neuroscience Bulletin
|July 23, 2025
Summary
Electrical brain stimulation can cause visual sensations, but they are unstable. This study found altered brain activity patterns, specifically flattened power spectral slopes and decreased integrated information, linked to these unstable visual sensations.
Area of Science:
- Neuroscience
- Cognitive Science
- Electrophysiology
Background:
- Direct electrical stimulation of the human cortex can evoke subjective visual sensations.
- The instability of these sensations suggests complex underlying neural mechanisms.
- Distributed network activity outside the stimulation site may play a crucial role.
Purpose of the Study:
- To investigate the electrophysiological mechanisms underlying unstable subjective visual sensations elicited by cortical stimulation.
- To identify specific brain network alterations associated with the presence or absence of visual sensations.
Main Methods:
- Recruited 69 patients undergoing invasive electrical stimulation for epilepsy or other neurological conditions.
- Recorded intracranial electroencephalography (iEEG) data during stimulation that elicited visual sensations and during non-sensation periods.
- Analyzed power spectral slopes and integrated information, and performed network analysis using minimum information partitions.
Main Results:
- Significantly flattened power spectral slopes were observed in distributed brain regions during elicited visual sensations compared to non-sensation conditions.
- Decreased integrated information was found during visual sensation periods.
- Reconfigured network interactions primarily involved the inferior frontal cortex, posterior superior temporal sulcus, and temporoparietal junction.
- Flattened power spectral slope in the inferior frontal gyrus correlated with integrated information.
Conclusions:
- Altered electrophysiological signatures, including flattened power spectral slopes and reduced integrated information, provide insights into the neural basis of subjective visual sensations.
- Network reconfiguration involving specific cortical regions is associated with the generation of these sensations.
- These findings contribute to understanding the neural dynamics of consciousness and perception.
Related Concept Videos
01:24Vision
Vision is the result of light being detected and transduced into neural signals by the retina of the eye. This information is then further analyzed and interpreted by the brain. First, light enters the front of the eye and is focused by the cornea and lens onto the retina—a thin sheet of neural tissue lining the back of the eye. Because of refraction through the convex lens of the eye, images are projected onto the retina upside-down and reversed.
02:26Photoelectric Effect
When light of a particular wavelength strikes a metal surface, electrons are emitted. This is called the photoelectric effect. The minimum frequency of light that can cause such emission of electrons is called the threshold frequency, which is specific to the metal. Light with a frequency lower than the threshold frequency, even if it is of high intensity, cannot initiate the emission of electrons. However, when the frequency is higher than the threshold value, the number of electrons ejected...
01:21G-Protein Gated Ion Channels
GPCRs are primarily responsible for our sense of smell, taste, and vision. The binding of a sensory stimulus activates GPCR to stimulate effector proteins, many of which are ion channels in the sensory organs. GPCRs modulate the opening and closing of the target ion channels either directly by binding them, or by releasing second messengers that activate these channels. As ions move across the membrane, the membrane potential is altered, which induces an appropriate response.
Sensory organs,...
Sensory organs,...
01:16Induction
An emf is induced when the magnetic field in a coil is changed by pushing a bar magnet into or out of the coil. emfs of opposite signs are produced by motion in opposite directions, and the directions of emfs are also reversed by reversing poles. The same results are produced if the coil is moved rather than the magnet—it is the relative motion that is important. The faster the motion, the greater the emf. Additionally, there is no emf when the magnet is stationary relative to the coil.
A...
A...
01:22Photoreceptors and Visual Pathways
At the molecular level, visual signals trigger transformations in photopigment molecules, resulting in changes in the photoreceptor cell's membrane potential. The photon's energy level is denoted by its wavelength, with each specific wavelength of visible light associated with a distinct color. The spectral range of visible light, classified as electromagnetic radiation, spans from 380 to 720 nm. Electromagnetic radiation wavelengths exceeding 720 nm fall under the infrared category, whereas...
01:30The Electrical Double Layer
In the region where two bulk phases meet, an intricate electric charge distribution arises due to charge transfer, ion adsorption, molecular orientation, and charge distortion. This complex distribution is commonly referred to as the electrical double layer.When a solid electrode interfaces with ions in an electrolyte solution, the speed of electron transfer dictates the rates of oxidation and reduction. The electrode acquires a charge through the escape of atoms into the solution as cations or...