67. Which of the following best allows a researcher to see activation of the visual cortex while a participant is looking at a photo and then see the activation decrease when the participant stops looking at the photo?
Answer: B
Functional magnetic resonance imaging (fMRI) best allows a researcher to see activation of the visual cortex while a participant is looking at a photo and then see the activation decrease when the participant stops looking at the photo.
fMRI provides detailed images of brain activity by measuring changes in blood flow, allowing researchers to observe the activation of the visual cortex in real-time as a participant views a photo, and subsequently, the decrease in activation when the participant stops looking.
A) Magnetic resonance imaging (MRI)
MRI is primarily used for structural imaging of the brain, providing detailed images of brain anatomy. However, it does not measure brain activity or changes in blood flow, making it unsuitable for observing the dynamic activation of the visual cortex in response to visual stimuli.
B) Functional magnetic resonance imaging (fMRI)
fMRI allows researchers to monitor brain activity by detecting changes in blood oxygenation level dependent (BOLD) signals. This technique is specifically designed to track real-time brain activity, making it ideal for observing the activation of the visual cortex while viewing a photo and the subsequent decrease in activation.
C) Computed tomography (CT)
CT scans provide cross-sectional images of the brain using X-rays, focusing on structural abnormalities rather than functional brain activity. Therefore, it cannot capture the dynamic changes in visual cortex activation related to visual tasks, rendering it ineffective for this type of research.
D) Electroencephalography (EEG)
EEG measures electrical activity in the brain through electrodes placed on the scalp. While it provides excellent temporal resolution for tracking changes in brain activity over time, it lacks the spatial resolution to pinpoint activation in specific brain regions like the visual cortex, making it less suitable for observing localized activation changes related to visual stimuli.
Conclusion
Functional magnetic resonance imaging (fMRI) is the only method among the options that provides both the spatial and temporal resolution necessary to observe the activation of the visual cortex in response to visual stimuli and the subsequent decrease in activity. Other methods, such as MRI, CT, and EEG, either lack the capability to measure functional changes or do not focus on the specific area of interest, confirming fMRI as the definitive choice for this research question.