title: Independent coding of absolute duration and distance magnitudes in the prefrontal cortex.
abstract: The estimation of space and time can interfere with each other, and neuroimaging studies have shown overlapping activation in the parietal and prefrontal cortical areas. We used duration and distance discrimination tasks to determine whether space and time share resources in prefrontal cortex (PF) neurons. Monkeys were required to report which of two stimuli, a red circle or blue square, presented sequentially, were longer and farther, respectively, in the duration and distance tasks. In a previous study, we showed that relative duration and distance are coded by different populations of neurons and that the only common representation is related to goal coding. Here, we examined the coding of absolute duration and distance. Our results support a model of independent coding of absolute duration and distance metrics by demonstrating that not only relative magnitude but also absolute magnitude are independently coded in the PF.
  
  
  
  Human behavioral studies have shown that spatial and duration judgments can interfere with each other. We investigated the neural representation of such magnitudes in the prefrontal cortex. We found that the two magnitudes are independently coded by prefrontal neurons. We suggest that the interference among magnitude judgments might depend on the goal rather than the perceptual resource sharing.
authors.affiliation: Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy.
authors.forename: Encarni
authors.initials: E
authors.lastname: Marcos
authors.affiliation: Department of Intelligence Science and Technology, Graduate School of Informatics, Kyoto University, Kyoto, Japan; and.|Nielsen Consumer Neuroscience, Tokyo, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Tsujimoto
authors.affiliation: Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy; aldo.genovesio@uniroma1.it.
authors.forename: Aldo
authors.initials: A
authors.lastname: Genovesio
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000704:Analysis of Variance; D000818:Animals; D004192:Discrimination, Psychological / Q000502:physiology*; D004215:Distance Perception / Q000502:physiology*; D008253:Macaca mulatta; D008297:Male; D008959:Models, Neurological; D009474:Neurons / Q000502:physiology*; D010364:Pattern Recognition, Visual / Q000502:physiology; D017397:Prefrontal Cortex / Q000166:cytology* / Q000502:physiology; D011930:Reaction Time / Q000502:physiology; D013998:Time Perception / Q000502:physiology*
keywords: magnitude; monkey; prefrontal; spatial; timing