Nicole L. Hair, Jamie L. Hanson, Barbara L. Wolfe, Seth D. Pollak, September 2015. The influence of poverty on children’s learning and achievement is mediated by structural brain development. To avoid long-term costs of impaired academic functioning, households below 150% of the federal poverty level should be targeted for additional resources aimed at remediating early childhood environments.
http://archpedi.jamanetwork.com/article.aspx?articleid=2381542#Introduction