title: Genotype- and sex-dependent effects of alteredCntnap2expression on the function of visual cortical areas.
abstract: BACKGROUND
  Autism spectrum disorder (ASD) is a heritable, heterogeneous neurodevelopmental disorder that is four times more likely to affect males than females. Despite this overt sex bias, it is unclear how genetic mutations associated with ASD alter cortical circuitry to produce the behavioral phenotypes by which ASD is diagnosed. Contactin-associated protein-like 2 (CNTNAP2) is an ASD-associated gene, and whileCntnap2knockout (KO) mice recapitulate many of the features of ASD, the effect on cortical circuitry is poorly understood. Moreover, although heterozygous (Het) mice are the more relevant genotype for ASD-linkedCNTNAP2mutations in humans, to our knowledge, no effects in Het mice have been previously reported.
  
  
  METHODS
  Intrinsic signal optical imaging was used to measure functional visual responses in primary and higher visual cortical areas in male and femaleCntnap2KO, Het, and wild-type (WT) mice. Main effect of genotype was assessed with one-way ANOVA. Visual responses were also measured in P17-18 and P30-32 KO and WT mice. Main effects of age and genotype were assessed using two-way ANOVA.
  
  
  RESULTS
  Visually evoked activity in dorsal stream associated higher visual areas in both KO and Het adult males was decreased relative to WT adult males. This decrease was not observed in adult females. Additionally, no significant difference was observed between WT and KO males at P17-18 with differences beginning to emerge at P30-32.
  
  
  CONCLUSIONS
  The functional responses of cortical circuitry in male mice are more strongly affected byCntnap2mutations than females, an effect present even in Hets. The observed differences in males emerge with development beginning at P30-32. These results reveal genotype- and sex-dependent effects of alteredCntnap2expression and can shed light on the sex-dependent incidence of ASD.
authors.affiliation: Neuroscience Curriculum, University of North Carolina at Chapel Hill, Chapel Hill, NC USA.
authors.forename: Leah B
authors.initials: LB
authors.lastname: Townsend
authors.affiliation: Neuroscience Curriculum, University of North Carolina at Chapel Hill, Chapel Hill, NC USA.|Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC USA.|Carolina Institute for Developmental Disabilities, University of North Carolina at Chapel Hill, Chapel Hill, NC USA.|Neuroscience Center, University of North Carolina at Chapel Hill, Chapel Hill, NC USA.
authors.forename: Spencer L
authors.initials: SL
authors.lastname: Smith
keywords: Autism; Cortical circuits; Higher visual areas; Intrinsic signal optical imaging; Mouse models; Sex