title: Functionally distinct amygdala subregions identified using DTI and high-resolution fMRI.
abstract: Although the amygdala is often directly linked with fear and emotion, amygdala neurons are activated by a wide variety of emotional and non-emotional stimuli. Different subregions within the amygdala may be engaged preferentially by different aspects of emotional and non-emotional tasks. To test this hypothesis, we measured and compared the effects of novelty and fear on amygdala activity. We used high-resolution blood oxygenation level-dependent (BOLD) imaging and streamline tractography to subdivide the amygdala into three distinct functional subunits. We identified a laterobasal subregion connected with the visual cortex that responds generally to visual stimuli, a non-projecting region that responds to salient visual stimuli, and a centromedial subregion connected with the diencephalon that responds only when a visual stimulus predicts an aversive outcome. We provide anatomical and functional support for a model of amygdala function where information enters through the laterobasal subregion, is processed by intrinsic circuits in the interspersed tissue, and is then passed to the centromedial subregion, where activation leads to behavioral output.
authors.affiliation: Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, USA, and.
authors.forename: Nicholas L
authors.initials: NL
authors.lastname: Balderston
authors.affiliation: Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, USA, and.
authors.forename: Douglas H
authors.initials: DH
authors.lastname: Schultz
authors.affiliation: Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, USA, and.
authors.forename: Lauren
authors.initials: L
authors.lastname: Hopkins
authors.affiliation: Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, USA, and Department of Neurology, Medical College of Wisconsin, Milwaukee, WI 53226, USA fjh@uwm.edu.
authors.forename: Fred J
authors.initials: FJ
authors.lastname: Helmstetter
mesh_terms: D000679:Amygdala / Q000033:anatomy & histology* / Q000502:physiology*; D003213:Conditioning, Psychological; D004027:Diencephalon / Q000033:anatomy & histology / Q000502:physiology; D056324:Diffusion Tensor Imaging; D004558:Electric Stimulation; D005239:Fear / Q000502:physiology; D005260:Female; D005712:Galvanic Skin Response; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009434:Neural Pathways / Q000033:anatomy & histology / Q000502:physiology; D010100:Oxygen / Q000097:blood; D010775:Photic Stimulation; D014793:Visual Cortex / Q000033:anatomy & histology / Q000502:physiology; D055815:Young Adult
chemical_list: D010100:Oxygen
keywords: amygdala; fMRI; fear conditioning; novelty; streamline tractography