Intrinsic signal changes accompanying sensory stimulation: functional brain mapping with magnetic resonance imaging.
AUTOR(ES)
Ogawa, S
RESUMO
We report that visual stimulation produces an easily detectable (5-20%) transient increase in the intensity of water proton magnetic resonance signals in human primary visual cortex in gradient echo images at 4-T magnetic-field strength. The observed changes predominantly occur in areas containing gray matter and can be used to produce high-spatial-resolution functional brain maps in humans. Reducing the image-acquisition echo time from 40 msec to 8 msec reduces the amplitude of the fractional signal change, suggesting that it is produced by a change in apparent transverse relaxation time T*2. The amplitude, sign, and echo-time dependence of these intrinsic signal changes are consistent with the idea that neural activation increases regional cerebral blood flow and concomitantly increases venous-blood oxygenation.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=402116Documentos Relacionados
- Magnetic resonance imaging.
- Dynamic magnetic resonance imaging of human brain activity during primary sensory stimulation.
- Identification of human brain regions underlying responses to resistive inspiratory loading with functional magnetic resonance imaging.
- Activation of single whisker barrel in rat brain localized by functional magnetic resonance imaging.
- Nuclear magnetic resonance imaging.
