title: The BOLD onset transient: identification of novel functional differences in schizophrenia.
abstract: Blood oxygen level dependent (BOLD) signals characteristically exhibit an overshoot (transient signal increase) at the beginning of fMRI task blocks. This onset transient has often been overlooked as an independent measure of neuronal activity, but it may represent unique functional processes. We examined onset transient responses in normal subjects and individuals with schizophrenia performing three cognitive tasks. These analyses revealed a regionally specific and task specific attenuation of the onset transient in individuals with schizophrenia during performance of a working memory task. Furthermore, this attenuation was often not accompanied by a corresponding population difference in the sustained response, and is missed through conventional fMRI analysis techniques. Relevance of these findings to both an interpretation of the onset transient and the pathology of schizophrenia are discussed.
authors.affiliation: Department of Radiology, Mallinckrodt Institute of Radiology, Washington University School of Medicine, 4525 Scott Avenue, St. Louis, MO 63110, USA. foxm@npg.wustl.edu
authors.forename: Michael D
authors.initials: MD
authors.lastname: Fox
authors.forename: Abraham Z
authors.initials: AZ
authors.lastname: Snyder
authors.forename: Mark P
authors.initials: MP
authors.lastname: McAvoy
authors.forename: Deanna M
authors.initials: DM
authors.lastname: Barch
authors.forename: Marcus E
authors.initials: ME
authors.lastname: Raichle
mesh_terms: D000328:Adult; D001143:Arousal / Q000502:physiology*; D001288:Attention / Q000502:physiology*; D001921:Brain / Q000098:blood supply; D001931:Brain Mapping; D005260:Female; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D007089:Image Enhancement; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008432:Mathematical Computing; D008570:Memory, Short-Term / Q000502:physiology; D010100:Oxygen / Q000097:blood*; D012016:Reference Values; D012153:Retention, Psychology / Q000502:physiology; D012559:Schizophrenia / Q000503:physiopathology*; D012565:Schizophrenic Psychology; D013223:Statistics as Topic; D014793:Visual Cortex / Q000098:blood supply
chemical_list: D010100:Oxygen