title: Dopamine and the mechanisms of cognition: Part I. A neural network model predicting dopamine effects on selective attention.
abstract: BACKGROUND
  Dopamine affects neural information processing, cognition, and behavior; however, the mechanisms through which these three levels of function are affected have remained unspecified. We present a parallel-distributed processing model of dopamine effects on neural ensembles that accounts for effects on human performance in a selective attention task.
  
  
  METHODS
  Task performance is stimulated using principles and mechanisms that capture salient aspects of information processing in neural ensembles. Dopamine effects are simulated as a change in gain of neural assemblies in the area of release.
  
  
  RESULTS
  The model leads to different predictions as a function of the hypothesized location of dopamine effects. Motor system effects are simulated as a change in gain over the response layer of the model. This induces speeding of reaction times but an impairment of accuracy. Cognitive attentional effects are simulated as a change in gain over the attention layer. This induces a speeding of reaction times and an improvement of accuracy, especially at very fast reaction times and when processing of the stimulus requires selective attention.
  
  
  CONCLUSIONS
  A computer simulation using widely accepted principles of processing in neural ensembles can account for reaction time distributions and time-accuracy curves in a selective attention task. The simulation can be used to generate predictions about the effects of dopamine agonists on performance. An empirical study evaluating these predictions is described in a companion paper.
authors.affiliation: Department of Psychiatry, University of Pittsburgh, Pennsylvania, USA.
authors.forename: D
authors.initials: D
authors.lastname: Servan-Schreiber
authors.forename: R M
authors.initials: RM
authors.lastname: Bruno
authors.forename: C S
authors.initials: CS
authors.lastname: Carter
authors.forename: J D
authors.initials: JD
authors.lastname: Cohen
mesh_terms: D001288:Attention / Q000502:physiology*; D001921:Brain / Q000502:physiology; D003071:Cognition / Q000502:physiology*; D004193:Discrimination Learning / Q000502:physiology; D004298:Dopamine / Q000502:physiology*; D006801:Humans; D016571:Neural Networks, Computer; D010364:Pattern Recognition, Visual / Q000502:physiology
chemical_list: D004298:Dopamine