Study of felines' DNA shows they probably got their start with humans guarding crops

Both skilled and unskilled players showed improved learning abilities in small study

But shrinkage seen in brain scans doesn't show impact on functioning, pro-pot experts say

But new finding needs additional research to confirm the link, experts caution

But experts say treatment should also focus on possible noncardiac causes of death

Study of felines' DNA shows they probably got their start with humans guarding crops

Both skilled and unskilled players showed improved learning abilities in small study

But shrinkage seen in brain scans doesn't show impact on functioning, pro-pot experts say

But new finding needs additional research to confirm the link, experts caution

White children more likely to be identified by schools, but researchers aren't sure what's behind this trend