title: Experimentally induced thyrotoxicosis leads to increased connectivity in temporal lobe structures: a resting state fMRI study.
abstract: Adult onset hyperthyroidism may impact on different cognitive domains, including attention and concentration, memory, perceptual function, language and executive function. Previous PET studies implicated changed functionality of limbic regions, the temporal and frontal lobes in hyperthyroidism, whereas it is unknown whether cognitive effects of hyperthyroidism may be due to changed brain connectivity. This study aimed to investigate the effect of experimentally induced short-term hyperthyroidism thyrotoxicosis on resting-state functional connectivity using functional magnetic resonance imaging. Twenty-nine healthy male right-handed subjects were examined twice, once prior and once after 8 weeks of oral administration of 250 μg levothyroxine per day. Resting-state fMRI was subjected to graph-theory based analysis methods to investigate whole-brain intrinsic functional connectivity. Despite a lack of subjective changes noticed by the subjects significant thyrotoxicosis was confirmed in all subjects. This induced a significant increase in resting-state functional connectivity specifically in the rostral temporal lobes (0.05 FDR corrected at the cluster level), which is caused by an increased connectivity to the cognitive control network. The increased connectivity between temporal poles and the cognitive control network shown here under experimental conditions supports an important function of thyroid hormones in the regulation of paralimbic structures.
authors: Department of Neurology, University of Lübeck, Lübeck, Germany.
authors: Martin
authors: M
authors: Göttlich
authors: Department of Neurology, University of Lübeck, Lübeck, Germany.
authors: Marcus
authors: M
authors: Heldmann
authors: Department of Neurology, University of Lübeck, Lübeck, Germany.
authors: Anna
authors: A
authors: Göbel
authors: Department of Internal Medicine I, University of Lübeck, Lübeck, Germany.
authors: Anna-Luise
authors: AL
authors: Dirk
authors: Department of Internal Medicine I, University of Lübeck, Lübeck, Germany.
authors: Georg
authors: G
authors: Brabant
authors: Department of Neurology, University of Lübeck, Lübeck, Germany. Electronic address: thomas.muente@neuro.uni-luebeck.de.
authors: Thomas F
authors: TF
authors: Münte
mesh_terms: D000328:Adult; D001288:Attention / Q000187:drug effects; D003071:Cognition; D003863:Depression / Q000139:chemically induced / Q000523:psychology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008032:Limbic System / Q000473:pathology; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009434:Neural Pathways / Q000473:pathology*; D009483:Neuropsychological Tests; D015203:Reproducibility of Results; D012146:Rest; D013702:Temporal Lobe / Q000473:pathology*; D013963:Thyroid Hormones / Q000097:blood; D013971:Thyrotoxicosis / Q000139:chemically induced / Q000473:pathology* / Q000523:psychology; D013974:Thyroxine / Q000633:toxicity; D014706:Verbal Learning / Q000187:drug effects; D055815:Young Adult
chemical_list: D013963:Thyroid Hormones; D013974:Thyroxine
keywords: Functional connectivity; Functional magnetic resonance imaging; Graph theory; Resting-state; Thyrotoxicosis; Voxel degree