title: Correlation Between Activation of the Prelimbic Cortex, Basolateral Amygdala, and Agranular Insular Cortex During Taste Memory Formation.
abstract: Conditioned taste aversion (CTA) is a well-established learning paradigm, whereby animals associate tastes with subsequent visceral illness. The prelimbic cortex (PL) has been shown to be involved in the association of events separated by time. However, the nature of PL activity and its functional network in the whole brain during CTA learning remain unknown. Here, using awake functional magnetic resonance imaging and fiber tracking, we analyzed functional brain connectivity during the association of tastes and visceral illness. The blood oxygen level-dependent (BOLD) signal significantly increased in the PL after tastant and lithium chloride (LiCl) infusions. The BOLD signal in the PL significantly correlated with those in the amygdala and agranular insular cortex (IC), which we found were also structurally connected to the PL by fiber tracking. To precisely examine these data, we then performed double immunofluorescence with a neuronal activity marker (c-Fos) and an inhibitory neuron marker (GAD67) combined with a fluorescent retrograde tracer in the PL. During CTA learning, we found an increase in the activity of excitatory neurons in the basolateral amygdala (BLA) or agranular IC that project to the PL. Taken together, these findings clearly identify a role of synchronized PL, agranular IC, and BLA activity in CTA learning.
authors.affiliation: Frontier Research Laboratories, Institute for Innovation, Ajinomoto Co., Inc., Kawasaki 210-8681, Japan Current address: Laboratory for Neural Circuitry of Memory, RIKEN Brain Science Institute, Saitama 351-0198, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Uematsu
authors.affiliation: Frontier Research Laboratories, Institute for Innovation, Ajinomoto Co., Inc., Kawasaki 210-8681, Japan.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Kitamura
authors.affiliation: Frontier Research Laboratories, Institute for Innovation, Ajinomoto Co., Inc., Kawasaki 210-8681, Japan Current address: Department of Nutritional Science and Food Safety, Tokyo University of Agriculture, Tokyo 156-8502, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Iwatsuki
authors.affiliation: Frontier Research Laboratories, Institute for Innovation, Ajinomoto Co., Inc., Kawasaki 210-8681, Japan.
authors.forename: Hisayuki
authors.initials: H
authors.lastname: Uneyama
authors.affiliation: Frontier Research Laboratories, Institute for Innovation, Ajinomoto Co., Inc., Kawasaki 210-8681, Japan.
authors.forename: Tomokazu
authors.initials: T
authors.lastname: Tsurugizawa
mesh_terms: D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects; D066272:Basolateral Nuclear Complex / Q000098:blood supply / Q000187:drug effects / Q000502:physiology*; D002540:Cerebral Cortex / Q000098:blood supply / Q000187:drug effects / Q000502:physiology*; D002772:Cholera Toxin / Q000378:metabolism; D038524:Diffusion Magnetic Resonance Imaging; D005968:Glutamate Decarboxylase / Q000378:metabolism; D007091:Image Processing, Computer-Assisted; D065726:Limbic Lobe / Q000098:blood supply / Q000187:drug effects / Q000502:physiology*; D018021:Lithium Chloride / Q000494:pharmacology; D008279:Magnetic Resonance Imaging; D008297:Male; D008568:Memory / Q000187:drug effects / Q000502:physiology*; D010100:Oxygen / Q000097:blood; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013223:Statistics as Topic; D013649:Taste / Q000187:drug effects / Q000502:physiology*
chemical_list: D016760:Proto-Oncogene Proteins c-fos; D002772:Cholera Toxin; D005968:Glutamate Decarboxylase; C402565:glutamate decarboxylase 1; D018021:Lithium Chloride; D010100:Oxygen
keywords: basolateral amygdala; fMRI; learning and memory; prelimbic cortex; taste aversion