title: Administration of exogenous melatonin increases spreading activation in lexical memory networks.
abstract: OBJECTIVE
  Several studies have examined the effect of exogenous melatonin on memory and cognitive functioning. Many of these investigations have reported improvement in recall and recognition as well as performance on various other indices of neuropsychological functioning. However, there have been no investigations reported that have examined the effects of exogenous melatonin administration on spreading activation in lexical and semantic memory networks. Hence, the purpose of this investigation was to determine the effects of melatonin on spreading activation.
  
  
  METHODS
  Participants were randomly assigned to either a 3-mg or 5-mg dose group, and spreading activation was measured both before and after administration. Spreading activation was measured by calculating the average word frequencies for words generated on the controlled oral word association test and the semantic fluency test.
  
  
  RESULTS
  A significant main effect for time was found, with the controlled oral word association test average word frequency being significantly higher at baseline than after taking melatonin. Also, a significant group × time interaction was found when using log transformed data. Multiple comparisons indicated that the 3-mg group exhibited significantly greater spreading activation following melatonin than the 5-mg group. The results indicate that melatonin may produce an increase in spreading activation in lexical memory networks. These results potentially provide an explanation for the benefits of melatonin on memory functioning.
authors.affiliation: Psychology Department, Middle Tennessee State University, Murfreesboro, TN, USA; Neurology Department, University of Florida, Gainesville, FL, USA.
authors.forename: Paul S
authors.initials: PS
authors.lastname: Foster
authors.forename: Ransom W
authors.initials: RW
authors.lastname: Campbell
authors.forename: Megan R
authors.initials: MR
authors.lastname: Williams
authors.forename: Kaylei K
authors.initials: KK
authors.lastname: Branch
authors.forename: Katelyn M
authors.initials: KM
authors.lastname: Roosa
authors.forename: Caitlin
authors.initials: C
authors.lastname: Orman
authors.forename: Valeria
authors.initials: V
authors.lastname: Drago
mesh_terms: D000328:Adult; D002492:Central Nervous System Depressants / Q000008:administration & dosage*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D008297:Male; D008550:Melatonin / Q000008:administration & dosage*; D008568:Memory / Q000187:drug effects*; D009483:Neuropsychological Tests; D012660:Semantics; D055815:Young Adult
chemical_list: D002492:Central Nervous System Depressants; D008550:Melatonin
keywords: lexical; melatonin; memory; semantic; spreading activation