title: Task-specific versus generalized mnemonic representations in parietal and prefrontal cortices.
abstract: Our ability to learn a wide range of behavioral tasks is essential for responding appropriately to sensory stimuli according to behavioral demands, but the underlying neural mechanism has been rarely examined by neurophysiological recordings in the same subjects across learning. To understand how learning new behavioral tasks affects neuronal representations, we recorded from posterior parietal cortex (PPC) before and after training on a visual motion categorization task. We found that categorization training influenced cognitive encoding in PPC, with a marked enhancement of memory-related delay-period encoding during the categorization task that was absent during a motion discrimination task before categorization training. In contrast, the prefrontal cortex (PFC) exhibited strong delay-period encoding during both discrimination and categorization tasks. This reveals a dissociation between PFC's and PPC's roles in working memory, with general engagement of PFC across multiple tasks, in contrast with more task-specific mnemonic encoding in PPC.
authors.affiliation: Department of Neurobiology, The University of Chicago, Chicago, Illinois, USA.
authors.forename: Arup
authors.initials: A
authors.lastname: Sarma
authors.affiliation: Department of Neurobiology, The University of Chicago, Chicago, Illinois, USA.
authors.forename: Nicolas Y
authors.initials: NY
authors.lastname: Masse
authors.affiliation: Center for Neural Science, New York University, New York, New York, USA.|NYU-ECNU Institute of Brain and Cognitive Science, NYU Shanghai, Shanghai, China.
authors.forename: Xiao-Jing
authors.initials: XJ
authors.lastname: Wang
authors.affiliation: Department of Neurobiology, The University of Chicago, Chicago, Illinois, USA.
authors.forename: David J
authors.initials: DJ
authors.lastname: Freedman
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D003210:Concept Formation / Q000502:physiology*; D004192:Discrimination, Psychological / Q000502:physiology*; D055724:Electrophysiological Phenomena; D007858:Learning / Q000502:physiology*; D008253:Macaca mulatta; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D009039:Motion Perception / Q000502:physiology; D009474:Neurons / Q000502:physiology; D010296:Parietal Lobe / Q000502:physiology*; D017397:Prefrontal Cortex / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology*; D013997:Time Factors; D014796:Visual Perception / Q000502:physiology*