title: Mapping functional brain activation using [14C]-iodoantipyrine in male serotonin transporter knockout mice.
abstract: BACKGROUND
  Serotonin transporter knockout mice have been a powerful tool in understanding the role played by the serotonin transporter in modulating physiological function and behavior. However, little work has examined brain function in this mouse model. We tested the hypothesis that male knockout mice show exaggerated limbic activation during exposure to an emotional stressor, similar to human subjects with genetically reduced transcription of the serotonin transporter.
  
  
  RESULTS
  Functional brain mapping using [(14)C]-iodoantipyrine was performed during recall of a fear conditioned tone. Regional cerebral blood flow was analyzed by statistical parametric mapping from autoradiographs of the three-dimensionally reconstructed brains. During recall, knockout mice compared to wild-type mice showed increased freezing, increased regional cerebral blood flow of the amygdala, insula, and barrel field somatosensory cortex, decreased regional cerebral blood flow of the ventral hippocampus, and conditioning-dependent alterations in regional cerebral blood flow in the medial prefrontal cortex (prelimbic, infralimbic, and cingulate). Anxiety tests relying on sensorimotor exploration showed a small (open field) or paradoxical effect (marble burying) of loss of the serotonin transporter on anxiety behavior, which may reflect known abnormalities in the knockout animal's sensory system. Experiments evaluating whisker function showed that knockout mice displayed impaired whisker sensation in the spontaneous gap crossing task and appetitive gap cross training.
  
  
  CONCLUSIONS
  This study is the first to demonstrate altered functional activation in the serotonin transporter knockout mice of critical nodes of the fear conditioning circuit. Alterations in whisker sensation and functional activation of barrel field somatosensory cortex extend earlier reports of barrel field abnormalities, which may confound behavioral measures relying on sensorimotor exploration.
authors: Graduate Program in Neuroscience, University of Southern California, Los Angeles, California, United States of America.
authors: Raina D
authors: RD
authors: Pang
authors: Zhuo
authors: Z
authors: Wang
authors: Lauren P
authors: LP
authors: Klosinski
authors: Yumei
authors: Y
authors: Guo
authors: David H
authors: DH
authors: Herman
authors: Tansu
authors: T
authors: Celikel
authors: Hong Wei
authors: HW
authors: Dong
authors: Daniel P
authors: DP
authors: Holschneider
mesh_terms: D000818:Animals; D000983:Antipyrine / Q000031:analogs & derivatives*; D001522:Behavior, Animal / Q000502:physiology; D001921:Brain / Q000098:blood supply; D001931:Brain Mapping / Q000379:methods*; D002250:Carbon Radioisotopes; D002560:Cerebrovascular Circulation / Q000502:physiology; D003213:Conditioning, Psychological; D005239:Fear / Q000502:physiology; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D050486:Serotonin Plasma Membrane Transport Proteins / Q000172:deficiency / Q000502:physiology*; D013003:Somatosensory Cortex; D014738:Vibrissae
chemical_list: D002250:Carbon Radioisotopes; D050486:Serotonin Plasma Membrane Transport Proteins; D000983:Antipyrine; C008135:iodoantipyrine