title: Functional connectivity and alterations in baseline brain state in humans.
abstract: This work examines the influence of changes in baseline activity on the intrinsic functional connectivity fMRI (fc-fMRI) in humans. Baseline brain activity was altered by inducing anesthesia (sevoflurane end-tidal concentration 1%) in human volunteers and fc-fMRI maps between the pre-anesthetized and anesthetized conditions were compared across different brain networks. We particularly focused on low-level sensory areas (primary somatosensory, visual, and auditory cortices), the thalamus, and pain (insula), memory (hippocampus) circuits, and the default mode network (DMN), the latter three to examine higher-order brain regions. The results indicate that, while fc-fMRI patterns did not significantly differ (p<0.005; 20-voxel cluster threshold) in sensory cortex and in the DMN between the pre- and anesthetized conditions, fc-fMRI in high-order cognitive regions (i.e. memory and pain circuits) was significantly altered by anesthesia. These findings provide further evidence that fc-fMRI reflects intrinsic brain properties, while also demonstrating that 0.5 MAC sevoflurane anesthesia preferentially modulates higher-order connections.
authors.affiliation: Department of Diagnostic Radiology, Yale University School of Medicine, The Anlyan Center, 300 Cedar Street, New Haven, CT 06520-8042, USA. roberto.martuzzi@yale.edu
authors.forename: Roberto
authors.initials: R
authors.lastname: Martuzzi
authors.forename: Ramachandran
authors.initials: R
authors.lastname: Ramani
authors.forename: Maolin
authors.initials: M
authors.lastname: Qiu
authors.forename: Nallakkandi
authors.initials: N
authors.lastname: Rajeevan
authors.forename: R Todd
authors.initials: RT
authors.lastname: Constable
mesh_terms: D000328:Adult; D000758:Anesthesia; D018685:Anesthetics, Inhalation; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008738:Methyl Ethers; D009415:Nerve Net / Q000033:anatomy & histology / Q000502:physiology; D009434:Neural Pathways / Q000033:anatomy & histology / Q000502:physiology*; D010146:Pain / Q000503:physiopathology / Q000523:psychology; D000077149:Sevoflurane; D055815:Young Adult
chemical_list: D018685:Anesthetics, Inhalation; D008738:Methyl Ethers; D000077149:Sevoflurane