title: Mapping brain activity during loss of situation awareness: an EEG investigation of a basis for top-down influence on perception.
abstract: OBJECTIVE
  The objective was to map brain activity during early intervals in loss of situation awareness (SA) to examine any co-activity in visual and high-order regions, reflecting grounds for top-down influences on Level I SA.
  
  
  BACKGROUND
  Behavioral and neuroscience evidence indicates that high-order brain areas can engage before perception is complete. Inappropriate top-down messages may distort perception during loss of SA. Evidence of co-activity of perceptual and high-order regions would not confirm such influence but may reflect a basis for it.
  
  
  METHODS
  SA and bias were measured using Quantitative Analysis of Situation Awareness and brain activity recorded with 128-channel EEG (electroencephalography) during loss of SA. One task (15 participants) required identification of a target pattern, and another task (10 participants) identification of "threat" in urban scenes. In both, the target was changed without warning, enforcing loss of SA. Key regions of brain activity were identified using source localization with standardized low-resolution electrical tomography (sLORETA) 150 to 160 ms post-stimulus onset in both tasks and also 100 to 110 ms in the second task.
  
  
  RESULTS
  In both tasks, there was significant loss of SA and bias shift (p < .02), associated at both 150- and 100-ms intervals with co-activity of visual regions and prefrontal, anterior cingulate and parietal regions linked to cognition under uncertainty.
  
  
  CONCLUSIONS
  There was early co-activity in high- order and visual perception regions that may provide a basis for top-down influence on perception.
  
  
  CONCLUSIONS
  Co-activity in high- and low-order brain regions may explain either beneficial or disruptive top-down influence on perception affecting Level I SA in real-world operations.
authors.forename: Di
authors.initials: D
authors.lastname: Catherwood
authors.forename: Graham K
authors.initials: GK
authors.lastname: Edgar
authors.forename: Dritan
authors.initials: D
authors.lastname: Nikolla
authors.forename: Chris
authors.initials: C
authors.lastname: Alford
authors.forename: David
authors.initials: D
authors.lastname: Brookes
authors.forename: Steven
authors.initials: S
authors.lastname: Baker
authors.forename: Sarah
authors.initials: S
authors.lastname: White
mesh_terms: D001288:Attention / Q000502:physiology; D001364:Awareness / Q000502:physiology*; D001931:Brain Mapping; D004569:Electroencephalography; D006801:Humans; D014796:Visual Perception / Q000502:physiology*