Micro-positron emission tomography imaging of rat brain metabolism during expression of contextual conditioning.
Using (18)F-fluorodeoxyglucose microPET imaging, we investigated the neurocircuitry of contextual anxiety versus control in awake, conditioned rats (n = 7-10 per group). In addition, we imaged a group expressing cued fear. Simultaneous measurements of startle amplitude and freezing time were used to assess conditioning. To the best of our knowledge, no neuroimaging studies in conditioned rats have been conducted thus far, although visualizing and quantifying the metabolism of the intact brain in behaving animals is clearly of interest. In addition, more insight into the neurocircuitry involved in contextual anxiety may stimulate the development of new treatments for anxiety disorders. Our main finding was hypermetabolism in a cluster comprising the bed nucleus of the stria terminalis (BST) in rats expressing contextual anxiety compared with controls. Analysis of a subset of rats showing the best behavioral results (n = 5 per subgroup) confirmed this finding. We also observed hypermetabolism in the same cluster in rats expressing contextual anxiety compared with rats expressing cued fear. Our results provide novel evidence for a role of the BST in the expression of contextual anxiety.
Division of Experimental Neurosurgery and Neuroanatomy, Katholieke Universiteit Leuven, 3000 Leuven, Belgium. laura.luyten@med.kuleuven.be
Laura
L
Luyten
Cindy
C
Casteels
Debora
D
Vansteenwegen
Kris
K
van Kuyck
Michel
M
Koole
Koen
K
Van Laere
Bart
B
Nuttin
D000679:Amygdala / Q000502:physiology; D000818:Animals; D001007:Anxiety / Q000378:metabolism*; D003213:Conditioning, Psychological / Q000502:physiology*; D004195:Disease Models, Animal; D004734:Energy Metabolism / Q000502:physiology*; D008297:Male; D009434:Neural Pathways / Q000502:physiology; D049268:Positron-Emission Tomography / Q000379:methods*; D051381:Rats; D017208:Rats, Wistar; D012686:Septal Nuclei / Q000033:anatomy & histology / Q000000981:diagnostic imaging* / Q000378:metabolism*