title: Caffeine differentially alters cortical hemodynamic activity during working memory: a near infrared spectroscopy study.
abstract: BACKGROUND
  Caffeine is a widely used stimulant with potentially beneficial effects on cognition as well as vasoconstrictive properties. In functional magnetic imaging research, caffeine has gained attention as a potential enhancer of the blood oxygenation level-dependent (BOLD) response. In order to clarify changes of oxy- and deoxyhemoglobin (HbO and HbR) induced by caffeine during a cognitive task, we investigated a working memory (WM) paradigm (visual 2-back) using near-infrared spectroscopy (NIRS).
  
  
  RESULTS
  Behaviorally, caffeine had no effect on the WM performance but influenced reaction times in the 0-back condition. NIRS data demonstrate caffeine-dependent alterations of the course of the hemodynamic response. The intake of 200 mg caffeine caused a significant decrease of the HbO response between 20 and 40 s after the onset of a 2-back task in the bilateral inferior frontal cortex (IFC). In parallel, the HbR response of the left IFC was significantly increased due to caffeine intake.
  
  
  CONCLUSIONS
  In line with previous results, we did not detect an effect of caffeine on most aspects of behavior. Effects of caffeine on brain vasculature were detected as general reduction of HbO. Neuronal effects of caffeine are reflected in an increased concentration of HbR in the left hemisphere when performing a verbal memory task and suggest influences on metabolism.
authors.affiliation: DZNE, German Center for Neurodegenerative Diseases, Otto-von-Guericke University, Magdeburg, Germany. urs.heilbronner@med.uni-muenchen.de.|Institute of Psychiatric Phenomics and Genomics, Ludwig-Maximilians-University, Munich, Germany. urs.heilbronner@med.uni-muenchen.de.
authors.forename: Urs
authors.initials: U
authors.lastname: Heilbronner
authors.affiliation: DZNE, German Center for Neurodegenerative Diseases, Otto-von-Guericke University, Magdeburg, Germany. hermann.hinrichs@med.ovgu.de.|LIN, Leibniz Institute for Neurobiology, Magdeburg, Germany. hermann.hinrichs@med.ovgu.de.|Department of Neurology, Otto-von-Guericke University, Magdeburg, Germany. hermann.hinrichs@med.ovgu.de.
authors.forename: Hermann
authors.initials: H
authors.lastname: Hinrichs
authors.affiliation: DZNE, German Center for Neurodegenerative Diseases, Otto-von-Guericke University, Magdeburg, Germany. heinze@med.ovgu.de.|LIN, Leibniz Institute for Neurobiology, Magdeburg, Germany. heinze@med.ovgu.de.|Department of Neurology, Otto-von-Guericke University, Magdeburg, Germany. heinze@med.ovgu.de.
authors.forename: Hans-Jochen
authors.initials: HJ
authors.lastname: Heinze
authors.affiliation: DZNE, German Center for Neurodegenerative Diseases, Otto-von-Guericke University, Magdeburg, Germany. tino.zaehle@ovgu.de.|LIN, Leibniz Institute for Neurobiology, Magdeburg, Germany. tino.zaehle@ovgu.de.|Department of Neurology, Otto-von-Guericke University, Magdeburg, Germany. tino.zaehle@ovgu.de.
authors.forename: Tino
authors.initials: T
authors.lastname: Zaehle
mesh_terms: D000328:Adult; D002110:Caffeine / Q000494:pharmacology*; D002540:Cerebral Cortex / Q000187:drug effects / Q000502:physiology*; D005260:Female; D006439:Hemodynamics / Q000187:drug effects*; D006801:Humans; D008297:Male; D008570:Memory, Short-Term / Q000187:drug effects / Q000502:physiology*; D013055:Spectrophotometry, Infrared / Q000379:methods*; D066127:White Matter / Q000187:drug effects / Q000502:physiology; D055815:Young Adult
chemical_list: D002110:Caffeine