title: A dynamic shift of neural network activity before and after learning-set formation.
abstract: Learning-set (LS) is a property of insight and hypothesis testing characterized by the ability to solve novel problems based on previous experiences with problem solving. However, the neural organization and mechanisms underlying LS remain unclear. To further characterize this process, positron emission tomography (PET) studies with [15O]H2O were performed to measure regional cerebral blood flow (rCBF) during the learning phase of the two-choice visual discrimination task under the LS paradigm in rhesus monkeys. When comparing studies before and after LS formation, the orbitofrontal and lateral prefrontal cortices were differentially activated, and functional connections between these structures and the striatum, which contributes to habit learning, were altered. We conclude that changes in the lateral prefrontal cortex during problem solving may contribute to the executive function of working memory and also inhibit control of a primitive learning system, thereby promoting LS formation.
authors.affiliation: Department of Psychiatry, Kyoto Prefectural University of Medicine Graduate School of Medical Science, 465 Kajii-cho, Kamigo-ku, Kyoto 602-8566, Japan.
authors.forename: Chihiro
authors.initials: C
authors.lastname: Yokoyama
authors.forename: Hideo
authors.initials: H
authors.lastname: Tsukada
authors.forename: Yasuyoshi
authors.initials: Y
authors.lastname: Watanabe
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Onoe
mesh_terms: D000818:Animals; D003213:Conditioning, Psychological / Q000502:physiology; D004193:Discrimination Learning / Q000502:physiology*; D008253:Macaca mulatta; D008297:Male; D009415:Nerve Net; D049268:Positron-Emission Tomography; D017397:Prefrontal Cortex / Q000000981:diagnostic imaging / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*