Neurobiology of speech and language has previously been studied in the KE family, in which half of the members have severe impairment in both speech and language. The gene responsible for the phenotype was mapped to chromosome 7q31 and identified as the FOXP2 gene, coding for a transcription factor containing a polyglutamine tract and a forkhead DNA-binding domain. Because of linkage studies implicating 7q31 in autism, where language impairment is a component of the disorder, and in specific language impairment, FOXP2 has also been considered as a potential susceptibility locus for the language deficits in autism and͞or specific language impairment. In this study, we characterized mice with a disruption in the murine

PARK8/LRRK2 (leucine-rich repeat kinase 2) was recently identified as a causative gene for autosomal dominant Parkinson's disease (PD), with LRRK2 mutation G2019S linked to the most frequent familial form of PD. Emerging in vitro evidence indicates that aberrant enzymatic activity of LRRK2 protein carrying this mutation can cause neurotoxicity. However, the physiological and pathophysiological functions of LRRK2 in vivo remain elusive. Here we characterize two bacterial artificial chromosome (BAC) transgenic mouse strains overexpressing LRRK2 wild-type (Wt) or mutant G2019S. Transgenic LRRK2-Wt mice had elevated striatal dopamine (DA) release with unaltered DA uptake or tissue content. Consistent with this result, LRRK2-Wt mice were hyperactive and showed enhanced performance in motor function tests. These results suggest a role for LRRK2 in striatal DA transmission and the consequent motor function. In contrast, LRRK2-G2019S mice showed an age-dependent decrease in striatal DA content, as well as decreased striatal DA release and uptake. Despite increased brain kinase activity, LRRK2-G2019S overexpression was not associated with loss of DAergic neurons in substantia nigra or degeneration of nigrostriatal terminals at 12 months. Our results thus reveal a pivotal role for LRRK2 in regulating striatal DA transmission and consequent control of motor function. The PD-associated mutation G2019S may exert pathogenic effects by impairing these functions of LRRK2. Our LRRK2 BAC transgenic mice, therefore, could provide a useful model for understanding early PD pathological events.

Blast related traumatic brain injury (TBI) has been a major cause of injury in the wars in Iraq and Afghanistan. A striking feature of the mild TBI (mTBI) cases has been the prominent association with post-traumatic stress disorder (PTSD). However, because of the overlapping symptoms, distinction between the two disorders has been difficult. We studied a rat model of mTBI in which adult male rats were exposed to repetitive blast injury while under anesthesia. Blast exposure induced a variety of PTSD-related behavioral traits that were present many months after the blast exposure, including increased anxiety, enhanced contextual fear conditioning, and an altered response in a predator scent assay. We also found elevation in the amygdala of the protein stathmin 1, which is known to influence the generation of fear responses. Because the blast overpressure injuries occurred while animals were under general anesthesia, our results suggest that a blastrelated mTBI exposure can, in the absence of any psychological stressor, induce PTSD-related traits that are chronic and persistent. These studies have implications for understanding the relationship of PTSD to mTBI in the population of veterans returning from the wars in Iraq and Afghanistan.