title: Glucose and caffeine effects on sustained attention: an exploratory fMRI study.
abstract: OBJECTIVE
  Caffeine and glucose can have beneficial effects on cognitive performance. However, neural basis of these effects remain unknown. Our objective was to evaluate the effects of caffeine and glucose on sustained attention, using functional magnetic resonance imaging (fMRI).
  
  
  METHODS
  Forty young right-handed, healthy, low caffeine-consuming subjects participated in the study. In a double-blind, randomised design, subjects received one of the following beverages: vehicle (water, 150 ml); vehicle plus 75 g of glucose; vehicle plus 75 mg of caffeine; vehicle plus 75 g of glucose and 75 mg of caffeine. Participants underwent two scanning fMRI sessions (before and 30 min after of the administration of the beverage). A continuous performance test was used to assess sustained attention.
  
  
  RESULTS
  Participants who received combined caffeine and glucose had similar performance to the others but had a decrease in activation in the bilateral parietal and left prefrontal cortex.
  
  
  CONCLUSIONS
  Since these areas have been related to the sustained attention and working memory processes, results would suggest that combined caffeine and glucose could increase the efficiency of the attentional system. However, more studies using larger samples and different levels of caffeine and glucose are necessary to better understand the combined effects of both substances.
authors.affiliation: Departament de Psiquiatria i Psicobiologia Clínica, Universitat de Barcelona, Barcelona, Spain. jmserra@ub.edu
authors.forename: Josep M
authors.initials: JM
authors.lastname: Serra-Grabulosa
authors.forename: Ana
authors.initials: A
authors.lastname: Adan
authors.forename: Carles
authors.initials: C
authors.lastname: Falcón
authors.forename: Núria
authors.initials: N
authors.lastname: Bargalló
mesh_terms: D000293:Adolescent; D000328:Adult; D001288:Attention / Q000187:drug effects*; D001786:Blood Glucose / Q000378:metabolism; D001921:Brain / Q000187:drug effects* / Q000502:physiology / Q000503:physiopathology; D002110:Caffeine / Q000493:pharmacokinetics / Q000494:pharmacology*; D000697:Central Nervous System Stimulants / Q000493:pharmacokinetics / Q000494:pharmacology*; D005260:Female; D007839:Functional Laterality; D005947:Glucose / Q000494:pharmacology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008568:Memory / Q000187:drug effects; D017397:Prefrontal Cortex / Q000187:drug effects; D013549:Sweetening Agents / Q000494:pharmacology*; D055815:Young Adult
chemical_list: D001786:Blood Glucose; D000697:Central Nervous System Stimulants; D013549:Sweetening Agents; D002110:Caffeine; D005947:Glucose