title: An fNIRS investigation of associative recognition in the prefrontal cortex with a rapid event-related design.
abstract: BACKGROUND
  Functional near-infrared spectroscopy (fNIRS) measures hemodynamic changes at the cortical level. The use of fNIRS is growing in popularity for studying cognitive neuroscience in which event-related designs are widely used with functional magnetic resonance imaging (fMRI). However, the applicability of event-related designs with fNIRS has not been fully understood. Therefore, the present study employed fNIRS with a rapid-presentation event-related design for investigating prefrontal cortical activity during complex associative recognition.
  
  
  METHODS
  Participants studied a list of word pairs and were later given an associative recognition test. Throughout the experiment, each event was presented rapidly (∼4s). Data were sorted based on accuracy of associative memory judgments and analyzed using the general linear model (GLM) with an event-related design.
  
  
  RESULTS
  During retrieval, significant increases in oxygenated hemoglobin concentrations were observed in dorsolateral and ventrolateral prefrontal regions for successful associative recognition. When comparing retrieval to encoding, significant increases in oxygenated hemoglobin concentrations were also observed in dorsolateral prefrontal cortex.
  
  
  CONCLUSIONS
  The current fNIRS results corroborate previous fMRI findings that have demonstrated the involvement of dorsolateral and ventrolateral prefrontal cortex in associative recognition. Therefore, the present study validates versatile use of fNIRS with a rapid-presentation event-related design in the investigation of neural mechanisms of associative memory.
  
  
  CONCLUSIONS
  The findings of this study provide evidence that fNIRS can be a viable research method for investigating complex cognitive processes commonly of interest in cognitive neuroscience. Taken together, these results demonstrate that fNIRS can be a cost-effective and accessible experimental tool for cognitive neuroscience.
authors: Department of Psychology, University of Texas at Arlington, United States.
authors: James D
authors: JD
authors: Schaeffer
authors: Department of Bioengineering, University of Texas at Arlington, United States.
authors: Amarnath S
authors: AS
authors: Yennu
authors: Department of Psychology, University of Texas at Arlington, United States.
authors: Kellen C
authors: KC
authors: Gandy
authors: Department of Bioengineering, University of Texas at Arlington, United States.
authors: Fenghua
authors: F
authors: Tian
authors: Department of Bioengineering, University of Texas at Arlington, United States. Electronic address: hanli@uta.edu.
authors: Hanli
authors: H
authors: Liu
authors: Department of Psychology, University of Texas at Arlington, United States. Electronic address: hkpark@uta.edu.
authors: Heekyeong
authors: H
authors: Park
mesh_terms: D000293:Adolescent; D000328:Adult; D001245:Association Learning / Q000502:physiology; D002560:Cerebrovascular Circulation; D005260:Female; D006439:Hemodynamics; D006801:Humans; D016014:Linear Models; D008297:Male; D009483:Neuropsychological Tests; D010364:Pattern Recognition, Visual / Q000502:physiology*; D017397:Prefrontal Cortex / Q000098:blood supply / Q000502:physiology*; D011932:Reading; D021641:Recognition, Psychology; D012815:Signal Processing, Computer-Assisted; D019265:Spectroscopy, Near-Infrared / Q000379:methods*; D055815:Young Adult
keywords: Associative memory; Cognition; Event-related design; fNIRS