@article{BenderReschKleinetal.2012,
  author    = {Bender, Stephan and Resch, Franz and Klein, Christoph and Renner, Tobias and Fallgatter, Andreas J. and Weisbrod, Matthias and Romanos, Marcel},
  title     = {Influence of Stimulant Medication and Response Speed on Lateralization of Movement-Related Potentials in Attention-Deficit/Hyperactivity Disorder},
  series = {PLoS One},
  volume    = {7},
  journal   = {PLoS One},
  number    = {6},
  doi       = {10.1371/journal.pone.0039012},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-135262},
  pages     = {e39012},
  year      = {2012},
  abstract  = {Background: Hyperactivity is one of the core symptoms in attention deficit hyperactivity disorder (ADHD). However, it remains unclear in which way the motor system itself and its development are affected by the disorder. Movement-related potentials (MRP) can separate different stages of movement execution, from the programming of a movement to motor post-processing and memory traces. Pre-movement MRP are absent or positive during early childhood and display a developmental increase of negativity. Methods: We examined the influences of response-speed, an indicator of the level of attention, and stimulant medication on lateralized MRP in 16 children with combined type ADHD compared to 20 matched healthy controls. Results: We detected a significantly diminished lateralisation of MRP over the pre-motor and primary motor cortex during movement execution (initial motor potential peak, iMP) in patients with ADHD. Fast reactions (indicating increased visuo-motor attention) led to increased lateralized negativity during movement execution only in healthy controls, while in children with ADHD faster reaction times were associated with more positive amplitudes. Even though stimulant medication had some effect on attenuating group differences in lateralized MRP, this effect was insufficient to normalize lateralized iMP amplitudes. Conclusions: A reduced focal (lateralized) motor cortex activation during the command to muscle contraction points towards an immature motor system and a maturation delay of the (pre-) motor cortex in children with ADHD. A delayed maturation of the neuronal circuitry, which involves primary motor cortex, may contribute to ADHD pathophysiology.},
  language  = {en}
}
@article{HavikDegenhardtJohanssonetal.2012,
  author    = {Havik, Bjarte and Degenhardt, Franziska A. and Johansson, Stefan and Fernandes, Carla P. D. and Hinney, Anke and Scherag, Andr{\´e} and Lybaek, Helle and Djurovic, Srdjan and Christoforou, Andrea and Ersland, Kari M. and Giddaluru, Sudheer and O'Donovan, Michael C. and Owen, Michael J. and Craddock, Nick and M{\"u}hleisen, Thomas W. and Mattheisen, Manuel and Schimmelmann, Benno G. and Renner, Tobias and Warnke, Andreas and Herpertz-Dahlmann, Beate and Sinzig, Judith and Albayrak, {\"O}zg{\"u}r and Rietschel, Marcella and N{\"o}then, Markus M. and Bramham, Clive R. and Werge, Thomas and Hebebrand, Johannes and Haavik, Jan and Andreassen, Ole A. and Cichon, Sven and Steen, Vidar M. and Le Hellard, Stephanie},
  title     = {DCLK1 Variants Are Associated across Schizophrenia and Attention Deficit/Hyperactivity Disorder},
  series = {PLoS One},
  volume    = {7},
  journal   = {PLoS One},
  number    = {4},
  doi       = {10.1371/journal.pone.0035424},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-135285},
  pages     = {e35424},
  year      = {2012},
  abstract  = {Doublecortin and calmodulin like kinase 1 (DCLK1) is implicated in synaptic plasticity and neurodevelopment. Genetic variants in DCLK1 are associated with cognitive traits, specifically verbal memory and general cognition. We investigated the role of DCLK1 variants in three psychiatric disorders that have neuro-cognitive dysfunctions: schizophrenia (SCZ), bipolar affective disorder (BP) and attention deficit/hyperactivity disorder (ADHD). We mined six genome wide association studies (GWASs) that were available publically or through collaboration; three for BP, two for SCZ and one for ADHD. We also genotyped the DCLK1 region in additional samples of cases with SCZ, BP or ADHD and controls that had not been whole-genome typed. In total, 9895 subjects were analysed, including 5308 normal controls and 4,587 patients (1,125 with SCZ, 2,496 with BP and 966 with ADHD). Several DCLK1 variants were associated with disease phenotypes in the different samples. The main effect was observed for rs7989807 in intron 3, which was strongly associated with SCZ alone and even more so when cases with SCZ and ADHD were combined (P-value = 4x10\(^{-5}\) and 4x10\(^{-6}\), respectively). Associations were also observed with additional markers in intron 3 (combination of SCZ, ADHD and BP), intron 19 (SCZ+BP) and the 3'UTR (SCZ+BP). Our results suggest that genetic variants in DCLK1 are associated with SCZ and, to a lesser extent, with ADHD and BP. Interestingly the association is strongest when SCZ and ADHD are considered together, suggesting common genetic susceptibility. Given that DCLK1 variants were previously found to be associated with cognitive traits, these results are consistent with the role of DCLK1 in neurodevelopment and synaptic plasticity.},
  language  = {en}
}