EEG measures brain activity and must demonstrate regular wave patterns to be considered valid. Therefore, by this rule the onset of life would be the time when fetal brain activity begins to exhibit regular wave patterns, which occurs fairly consistently around week 25. read more
Third trimester: Baby's brain grows. The third trimester is brimming with rapid development of neurons and wiring. Baby's brain roughly triples in weight during the last 13 weeks of gestation, growing from about 3.5 ounces at the end the second trimester to almost 10.6 ounces at term. read more
In the new study, published online in August 2016 in the journal Human Brain Mapping, researchers aimed to create a four-dimensional movie of fetal default mode network activity. To do this, they used functional MRI—a technique that detects brain activity based on blood flow; active regions have higher levels of blood flowing to them. read more