RT Journal
A1 Courchesne E, Mouton PR, Calhoun ME, et al
T1 NEuron number and size in prefrontal cortex of children with autism
JF JAMA
JO JAMA
YR 2011
FD November 9
VO 306
IS 18
SP 2001
OP 2010
DO 10.1001/jama.2011.1638
UL http://dx.doi.org/10.1001/jama.2011.1638
AB Context 
                  Autism often involves early brain overgrowth, including the prefrontal cortex (PFC). Although prefrontal abnormality has been theorized to underlie some autistic symptoms, the cellular defects that cause abnormal overgrowth remain unknown.Objective 
                  To investigate whether early brain overgrowth in children with autism involves excess neuron numbers in the PFC.Design, Setting, and Cases 
                  Postmortem prefrontal tissue from 7 autistic and 6 control male children aged 2 to 16 years was examined by expert anatomists who were blinded to diagnostic status. Number and size of neurons were quantified using stereological methods within the dorsolateral (DL-PFC) and mesial (M-PFC) subdivisions of the PFC. Cases were from the eastern and southeastern United States and died between 2000 and 2006.Main Outcome Measures 
                  Mean neuron number and size in the DL-PFC and M-PFC were compared between autistic and control postmortem cases. Correlations of neuron number with deviation in brain weight from normative values for age were also performed.Results 
                  Children with autism had 67% more neurons in the PFC (mean, 1.94 billion; 95% CI, 1.57-2.31) compared with control children (1.16 billion; 95% CI, 0.90-1.42; P = .002), including 79% more in DL-PFC (1.57 billion; 95% CI, 1.20-1.94 in autism cases vs 0.88 billion; 95% CI, 0.66-1.10 in controls; P = .003) and 29% more in M-PFC (0.36 billion; 95% CI, 0.33-0.40 in autism cases vs 0.28 billion; 95% CI, 0.23-0.34 in controls; P = .009). Brain weight in the autistic cases differed from normative mean weight for age by a mean of 17.6% (95% CI, 10.2%-25.0%; P = .001), while brains in controls differed by a mean of 0.2% (95% CI, −8.7% to 9.1%; P = .96). Plots of counts by weight showed autistic children had both greater total prefrontal neuron counts and brain weight for age than control children.Conclusion 
                  In this small preliminary study, brain overgrowth in males with autism involved an abnormal excess number of neurons in the PFC.