For decades, neuroscientists have been searching for an unmistakable signal of consciousness in electrical brain activity. Such a sign could determine whether minimally conscious or anesthetized adults are aware—and when consciousness begins in babies.
Studies on adults show a particular pattern of brain activity: When your senses detect something, such as a moving object, the vision center of your brain activates, even if the object goes by too fast for you to notice. But if the object remains in your visual field for long enough, the signal travels from the back of the brain to the prefrontal cortex, which holds the image in your mind long enough for you to notice. Scientists see a spike in brain activity when the senses pick something up, and another signal, the "late slow wave," when the prefrontal cortex gets the message. The whole process takes less than one-third of a second.
Researchers in France wondered if such a two-step pattern might be present in infants. The team monitored infants' brain activity through caps fitted with electrodes. . . . In babies who were at least 1 year old, [the researchers] saw an ERP pattern similar to an adult's, but it was about three times slower. The team was surprised to see that the 5-month-olds also showed a late slow wave, although it was weaker and more drawn out than in the older babies. Kouider speculates that the late slow wave may be present in babies as young as 2 months.
Friday, April 19, 2013
When Do Babies Become Conscious?
According to this study, they show glimmers of consciousness when they are about 5 months old and are fully conscious by one year. Which makes sense to me; I mean, I loved my newborn babies, but they didn't seem very human.