Related Experiment Video

Updated: Jul 15, 2026

Multiscale Investigations of Cortical Processing by Integrating Laminar Polytrodes and Optogenetics with Micro Electrocorticography in Rodents
07:52

Multiscale Investigations of Cortical Processing by Integrating Laminar Polytrodes and Optogenetics with Micro Electrocorticography in Rodents

Published on: May 23, 2025

Functional organization of human visual cortex in occipital polymicrogyria

Serge O Dumoulin1, Jeffrey D Jirsch, Andrea Bernasconi

  • 1McGill Vision Research Unit, Department of Ophthalmology, McGill University, Montréal, Canada. serge.dumoulin@stanford.edu

Human Brain Mapping
|April 18, 2007
PubMed

Insights

Polymicrogyrias (PMG), a brain malformation, do not impair visual processing in affected areas. This study found that the polymicrogyric cortex is functionally organized and actively processes visual information, contributing to normal vision.

Area of Science:

  • Neuroscience
  • Developmental Neuroscience
  • Neuroimaging

Background:

  • Polymicrogyrias (PMG) are cortical malformations arising from abnormal brain development.
  • Animal models suggest PMG is linked to altered brain anatomy, function, and organization.
  • Understanding PMG's impact on human brain function is crucial for clinical insights.

Purpose of the Study:

  • To investigate the functional organization of human polymicrogyric cortex.
  • To assess visual processing capabilities in individuals with PMG.
  • To utilize functional magnetic resonance imaging (fMRI) for detailed analysis.

Main Methods:

  • Phase-encoded retinotopic mapping was employed to reconstruct visual cortex organization.
  • fMRI was used to analyze cortical responses in three epilepsy patients with occipital PMG.
  • Visual field perimetry confirmed normal vision in the studied patients.

Main Results:

  • Early visual areas (V1, V2, V3/VP) showed normal cortical responses and organization.
  • These functionally identified visual areas largely overlapped with polymicrogyric regions.
  • In most hemispheres, the primary visual cortex was located within the PMG.

Conclusions:

  • Human polymicrogyric cortex exhibits normal functional organization.
  • Despite malformation, PMG areas actively participate in visual information processing.
  • PMG does not necessarily impede normal visual perception or cortical function.

More Related Videos

Large-scale Three-dimensional Imaging of Cellular Organization in the Mouse Neocortex09:55

Large-scale Three-dimensional Imaging of Cellular Organization in the Mouse Neocortex

Published on: September 5, 2018

Visualization of Cortical Modules in Flattened Mammalian Cortices08:49

Visualization of Cortical Modules in Flattened Mammalian Cortices

Published on: January 22, 2018

Related Concept Videos

Association Areas of the Cortex01:21

Association Areas of the Cortex

Association areas are regions of the cerebral cortex that do not have a specific sensory or motor function. Instead, they integrate and interpret information from various sources to enable higher cognitive processes such as memory, learning, and decision-making. Some key association areas include the following:
Prefrontal Association Area: This area is located in the frontal lobe and is involved in planning, decision-making, and moderating social behavior. It connects with primary motor areas,...
Motor and Sensory Areas of the Cortex01:14

Motor and Sensory Areas of the Cortex

The cerebral cortex, the brain's outermost layer, is pivotal in processing complex cognitive tasks, emotions, and various sensory inputs and executing voluntary motor activities. This intricate structure is divided into three primary functional areas: the motor areas, sensory areas, and association areas.
Motor Areas
The motor areas located in the frontal lobe are central to controlling voluntary movements. This region is further subdivided into the primary motor cortex and the premotor cortex.
Vision01:24

Vision

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.
Anatomy of the Eyeball01:20

Anatomy of the Eyeball

The eye is a spherical, hollow structure composed of three tissue layers. The outer layer — the fibrous tunic, comprises the sclera — a white structure — and the cornea, which is transparent. The sclera encompasses some of the ocular surface, most of which is not visible. However, the 'white of the eye' is distinctively visible in humans compared to other species. The cornea, a clear covering at the front of the eye, enables light penetration. The eye's middle layer, the vascular tunic,...
Somatosensory, Motor, and Association Cortex01:23

Somatosensory, Motor, and Association Cortex

The somatosensory cortex in the parietal lobes is crucial for interpreting sensory data such as touch, temperature, and proprioception. The somatosensory cortex, situated in the parietal lobes, plays a vital role in interpreting sensory information like touch, temperature, and proprioception—awareness of body position. This specialized brain region features an organized structure wherein neurons at the top primarily process sensations originating from the lower body. In contrast, those at the...
Organization of the Brain01:31

Organization of the Brain

The brain is an integral component of the nervous system and serves as the center for processing sensory inputs, making decisions, and directing bodily actions. This complex organ is organized into three primary sections: the hindbrain, midbrain, and forebrain, each responsible for a range of vital functions.
Hindbrain
The hindbrain, located at the base of the brain, plays a vital role in regulating automatic processes that sustain life. It includes the medulla oblongata, which is essential for...