4 ms·
The following is my understanding, but I could be wrong: When neurons activate, they release a neurotransmitter (typically glutamate) that then binds to nearby
by nvrspyx 6y ago
The following is my understanding, but I could be wrong:
When neurons activate, they release a neurotransmitter (typically glutamate) that then binds to nearby astrocytes. Astrocytes then increase their intracellular calcium levels which in turn causes vascular dilation of the nearby area, thus increasing blood flow to that area.
- hliyan 6y agoThanks, this was what I was looking for. So I guess this pathway is not very predictable, hence the variations in subsequent measurements of the same subject.
- jrumbut 6y agoAlso consider aligning the images to process them all with a single model, the different sized/shaped heads in the world and correcting for their different angles and little bits of movement. That's not even considering differences between brains. I am continually amazed at the level of automated preprocessing tools to deal with this alignment problem. You can play around with fMRI data using some popular packages without thinking too hard about it and produce visualizations almost as nice looking as the ones in the article.
- brainmapper 6y agoThe most sensitive fMRI methods don't do alignment at all, they do all data processing in the individual subject's brain space.
- brainmapper 6y agoMuch of the day-to-day variation concerns uncontrolled variability in blood pressure, arousal and attention. Those factors have enormous influence on the blood-oxygen-level-dependent signal.