Dopaminergic Neuronal Loss, Reduced Neurite Complexity and Autophagic Abnormalities in Transgenic Mice Expressing G2019S Mutant LRRK2

Mutations in the leucine-rich repeat kinase 2 (LRRK2) gene cause late-onset, autosomal dominant familial Parkinson's disease (PD) and also contribute to idiopathic PD. LRRK2 mutations represent the most common cause of PD with clinical and neurochemical features that are largely indistinguishable from idiopathic disease. Currently, transgenic mice expressing wild-type or disease-causing mutants of LRRK2 have failed to produce overt neurodegeneration, although abnormalities in nigrostriatal dopaminergic neurotransmission have been observed. Here, we describe the development and characterization of transgenic mice expressing human LRRK2 bearing the familial PD mutations, R1441C and G2019S. Our study demonstrates that expression of G2019S mutant LRRK2 induces the degeneration of nigrostriatal pathway dopaminergic neurons in an age-dependent manner. In addition, we observe autophagic and mitochondrial abnormalities in the brains of aged G2019S LRRK2 mice and markedly reduced neurite complexity of cultured dopaminergic neurons. These new LRRK2 transgenic mice will provide important tools for understanding the mechanism(s) through which familial mutations precipitate neuronal degeneration and PD

Electronic gaming: Associations with self-regulation, emotional difficulties and academic performance

Drawing on data from the Longitudinal Study of Australian Children (LSAC), this chapter reports on the use of electronic games by young children (8-9 years old) and the associations with cognitive self-regulation, academic performance (mathematics, language and literacy) and emotional difficulties two years later when children were 10-11 years of age. Results indicated that, compared to children who played electronic games for 120 minutes or less per week, playing games for between 121 and 240 minutes per week was associated with better scores on Language and Literacy and Mathematical Thinking at 10 to 11 years of age. Conversely, use of electronic games for more than an hour per day (more than 421 minutes per week) was associated with lower cognitive self-regulation and an increase in emotional difficulties at 10-11 years of age