title: Rapidly acquired multisensory association in the olfactory cortex.
abstract: BACKGROUND
  The formation of an odor percept in humans is strongly associated with visual information. However, much less is known about the roles of learning and memory in shaping the multisensory nature of odor representations in the brain.
  
  
  METHODS
  The dynamics of odor and visual association in olfaction was investigated using three functional magnetic resonance imaging (fMRI) paradigms. In two paradigms, a visual cue was paired with an odor. In the third, the same visual cue was never paired with an odor. In this experimental design, if the visual cue was not influenced by odor-visual pairing, then the blood-oxygen-level-dependent (BOLD) signal elicited by subsequent visual cues should be similar across all three paradigms. Additionally, intensity, a major dimension of odor perception, was used as a modulator of associative learning which was characterized in terms of the spatiotemporal behavior of the BOLD signal in olfactory structures.
  
  
  RESULTS
  A single odor-visual pairing cue could subsequently induce primary olfactory cortex activity when only the visual cue was presented. This activity was intensity dependent and was also detected in secondary olfactory structures and hippocampus.
  
  
  CONCLUSIONS
  This study provides evidence for a rapid learning response in the olfactory system by a visual cue following odor and visual cue pairing. The novel data and paradigms suggest new avenues to explore the dynamics of odor learning and multisensory representations that contribute to the construction of a unified odor percept in the human brain.
authors.affiliation: Department of Radiology (Center for NMR Research) The Pennsylvania State University College of Medicine Hershey Pennsylvania.
authors.forename: Prasanna R
authors.initials: PR
authors.lastname: Karunanayaka
authors.affiliation: Emotional Brain Institute Nathan S. Kline Institute for Psychiatric Research Orangeburg New York ; Department of Child & Adolescent Psychiatry New York University School of Medicine New York City New York.
authors.forename: Donald A
authors.initials: DA
authors.lastname: Wilson
authors.affiliation: Department of Radiology (Center for NMR Research) The Pennsylvania State University College of Medicine Hershey Pennsylvania.
authors.forename: Megha
authors.initials: M
authors.lastname: Vasavada
authors.affiliation: Department of Radiology (Center for NMR Research) The Pennsylvania State University College of Medicine Hershey Pennsylvania.
authors.forename: Jianli
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Radiology (Center for NMR Research) The Pennsylvania State University College of Medicine Hershey Pennsylvania.
authors.forename: Brittany
authors.initials: B
authors.lastname: Martinez
authors.affiliation: Department of Radiology (Center for NMR Research) The Pennsylvania State University College of Medicine Hershey Pennsylvania.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Tobia
authors.affiliation: Department of Public Health Sciences The Pennsylvania State University College of Medicine Hershey Pennsylvania.
authors.forename: Lan
authors.initials: L
authors.lastname: Kong
authors.affiliation: Department of Radiology (Center for NMR Research) The Pennsylvania State University College of Medicine Hershey Pennsylvania ; Department of Neurology The Pennsylvania State University College of Medicine Hershey Pennsylvania.
authors.forename: Paul
authors.initials: P
authors.lastname: Eslinger
authors.affiliation: Department of Radiology (Center for NMR Research) The Pennsylvania State University College of Medicine Hershey Pennsylvania ; Department of Neurosurgery The Pennsylvania State University College of Medicine Hershey Pennsylvania.
authors.forename: Qing X
authors.initials: QX
authors.lastname: Yang
mesh_terms: D000328:Adult; D001245:Association Learning / Q000502:physiology*; D001931:Brain Mapping; D003214:Conditioning, Classical; D003463:Cues; D005260:Female; D006624:Hippocampus / Q000502:physiology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008568:Memory / Q000502:physiology*; D009812:Odorants; D066194:Olfactory Cortex / Q000166:cytology / Q000502:physiology*; D018034:Olfactory Receptor Neurons / Q000502:physiology; D010775:Photic Stimulation; D012903:Smell / Q000502:physiology
keywords: ICA; associative learning; fMRI; odor intensity; unified SEM