Biomaterial Database

Neuromagnetic responses to chromatic flicker: implications for photosensitivity. 2002

Katsumi Watanabe, and Toshiaki Imada, and Kenji Nihei, and Shinsuke Shimojo

Computation and Neural Systems, Division of Biology, California Institute of Technology, MC 139-74, Pasadena, CA 91125, USA.

Excessive cortical excitation due to visual stimulation often leads to photosensitive epilepsy. Here we demonstrate that even in normal subjects, prolonged stimulation with low-luminance chromatic (equiluminant) flicker evokes neuromagnetic activity in the primary visual cortex, which develops slowly (up to 1000 ms) and depends on the color combination of flicker. This result suggests that chromatic sensitivity is a critical factor of cortical excitation, which can be amplified over time by a flickering stimulus. We further show that transient activity occurs in the parieto-occipital sulcus as early as 100-400 ms after flicker onset, which is negatively correlated with the later occipital activity. The early parieto-occipital activity may reflect a defensive mechanism that suppresses cortical hyperactivity due to chromatic flicker.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D009778	Occipital Lobe	Posterior portion of the CEREBRAL HEMISPHERES responsible for processing visual sensory information. It is located posterior to the parieto-occipital sulcus and extends to the preoccipital notch.	Annectant Gyrus,Calcarine Fissure,Calcarine Sulcus,Cuneate Lobule,Cuneus,Cuneus Cortex,Cuneus Gyrus,Gyrus Lingualis,Lingual Gyrus,Lunate Sulcus,Medial Occipitotemporal Gyrus,Occipital Cortex,Occipital Gyrus,Occipital Region,Occipital Sulcus,Sulcus Calcarinus,Calcarine Fissures,Calcarinus, Sulcus,Cortex, Cuneus,Cortex, Occipital,Cortices, Cuneus,Cortices, Occipital,Cuneate Lobules,Cuneus Cortices,Fissure, Calcarine,Fissures, Calcarine,Gyrus Linguali,Gyrus, Annectant,Gyrus, Cuneus,Gyrus, Lingual,Gyrus, Medial Occipitotemporal,Gyrus, Occipital,Linguali, Gyrus,Lingualis, Gyrus,Lobe, Occipital,Lobes, Occipital,Lobule, Cuneate,Lobules, Cuneate,Occipital Cortices,Occipital Lobes,Occipital Regions,Occipitotemporal Gyrus, Medial,Region, Occipital,Regions, Occipital,Sulcus, Calcarine,Sulcus, Lunate,Sulcus, Occipital
D010296	Parietal Lobe	Upper central part of the cerebral hemisphere. It is located posterior to central sulcus, anterior to the OCCIPITAL LOBE, and superior to the TEMPORAL LOBES.	Brodmann Area 39,Brodmann Area 40,Brodmann Area 5,Brodmann Area 7,Brodmann's Area 39,Brodmann's Area 40,Brodmann's Area 5,Brodmann's Area 7,Inferior Parietal Cortex,Secondary Sensorimotor Cortex,Superior Parietal Lobule,Angular Gyrus,Gyrus Angularis,Gyrus Supramarginalis,Intraparietal Sulcus,Marginal Sulcus,Parietal Cortex,Parietal Lobule,Parietal Region,Posterior Paracentral Lobule,Posterior Parietal Cortex,Praecuneus,Precuneus,Precuneus Cortex,Prelunate Gyrus,Supramarginal Gyrus,Area 39, Brodmann,Area 39, Brodmann's,Area 40, Brodmann,Area 40, Brodmann's,Area 5, Brodmann,Area 5, Brodmann's,Area 7, Brodmann,Area 7, Brodmann's,Brodmanns Area 39,Brodmanns Area 40,Brodmanns Area 5,Brodmanns Area 7,Cortex, Inferior Parietal,Cortex, Parietal,Cortex, Posterior Parietal,Cortex, Precuneus,Cortex, Secondary Sensorimotor,Cortices, Inferior Parietal,Gyrus, Angular,Gyrus, Prelunate,Gyrus, Supramarginal,Inferior Parietal Cortices,Lobe, Parietal,Lobule, Parietal,Lobule, Posterior Paracentral,Lobule, Superior Parietal,Paracentral Lobule, Posterior,Paracentral Lobules, Posterior,Parietal Cortex, Inferior,Parietal Cortex, Posterior,Parietal Cortices,Parietal Cortices, Inferior,Parietal Cortices, Posterior,Parietal Lobes,Parietal Lobule, Superior,Parietal Lobules,Parietal Lobules, Superior,Parietal Regions,Posterior Paracentral Lobules,Posterior Parietal Cortices,Precuneus Cortices,Region, Parietal,Secondary Sensorimotor Cortices,Sensorimotor Cortex, Secondary,Superior Parietal Lobules
D010775	Photic Stimulation	Investigative technique commonly used during ELECTROENCEPHALOGRAPHY in which a series of bright light flashes or visual patterns are used to elicit brain activity.	Stimulation, Photic,Visual Stimulation,Photic Stimulations,Stimulation, Visual,Stimulations, Photic,Stimulations, Visual,Visual Stimulations
D012016	Reference Values	The range or frequency distribution of a measurement in a population (of organisms, organs or things) that has not been selected for the presence of disease or abnormality.	Normal Range,Normal Values,Reference Ranges,Normal Ranges,Normal Value,Range, Normal,Range, Reference,Ranges, Normal,Ranges, Reference,Reference Range,Reference Value,Value, Normal,Value, Reference,Values, Normal,Values, Reference
D003116	Color	The visually perceived property of objects created by absorption or reflection of specific wavelengths of light.	Colors
D003118	Color Perception	Mental processing of chromatic signals (COLOR VISION) from the eye by the VISUAL CORTEX where they are converted into symbolic representations. Color perception involves numerous neurons, and is influenced not only by the distribution of wavelengths from the viewed object, but also by its background color and brightness contrast at its boundary.	Color Perceptions,Perception, Color,Perceptions, Color
D005260	Female		Females
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000328	Adult	A person having attained full growth or maturity. Adults are of 19 through 44 years of age. For a person between 19 and 24 years of age, YOUNG ADULT is available.	Adults