title: Application of a neuropsychological activation probe with SPECT: the 'Tower of London' task in healthy volunteers.
abstract: BACKGROUND
  Human planning is a complex mental process that may be evaluated by the 'Tower of London' (TOL) task, which includes setting up and maintaining multiple subgoals at the same time. Although positron emission tomography and functional magnetic resonance imaging have provided reliable data on the recruitment of a neural network engaged in planning tasks, the experimental settings of these studies cannot be applied in clinical conditions. Hence, this study reports on the TOL task under classical neuropsychological test conditions using single photon emission computed tomography (SPECT) activation in 10 healthy subjects.
  
  
  METHODS
  Participants first performed a control task and then an activation task, i.e., the TOL planning task In the planning task, subjects were required to change, in the minimum number of moves possible, an initial arrangement of beads to match a goal arrangement. Subjects solved a set of eight TOL problems of increasing difficulty. A control task was designed such that it eliminates planning abilities, which is the process of interest. Planning times and accuracy were measured as performance parameters and functional imaging data were analysed with statistical parametric mapping (SPM99) to determine significant voxel-wise activations between the planning task and the control task.
  
  
  RESULTS
  Both overall and for each difficulty level, measures of accuracy were within the normal range. Similar results were found for the overall thinking time and thinking times of each difficulty level. That is, performance of the healthy subjects during the TOL task replicated the typical pattern of results found with appropriate control samples in the literature. Also, activation of the right prefrontal cortex was consistent with other functional imaging results, thereby validating the use of the TOL task in a SPECT activation paradigm.
  
  
  CONCLUSIONS
  Based on the present study it may be concluded that the close resemblance of the test conditions of the SPECT activation procedure with those of the TOL task in the investigation room constitutes a major advantage for future application of the SPECT activation procedure in clinical conditions.
authors.affiliation: Division of Nuclear Medicine, Ghent University Hospital, Ghent, Belgium. ingeborg.goethals@ugent.be
authors.forename: Ingeborg
authors.initials: I
authors.lastname: Goethals
authors.forename: Kurt
authors.initials: K
authors.lastname: Audenaert
authors.forename: Filip
authors.initials: F
authors.lastname: Jacobs
authors.forename: Christophe
authors.initials: C
authors.lastname: Van de Wiele
authors.forename: Hanneke
authors.initials: H
authors.lastname: Pyck
authors.forename: Hamphrey
authors.initials: H
authors.lastname: Ham
authors.forename: André
authors.initials: A
authors.lastname: Vandierendonck
authors.forename: Cees
authors.initials: C
authors.lastname: van Heeringen
authors.forename: Rudi
authors.initials: R
authors.lastname: Dierckx
mesh_terms: D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging* / Q000502:physiology*; D003545:Cysteine / Q000031:analogs & derivatives*; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008606:Mental Processes / Q000502:physiology; D008875:Middle Aged; D009483:Neuropsychological Tests; D015609:Organotechnetium Compounds; D017397:Prefrontal Cortex / Q000000981:diagnostic imaging; D019275:Radiopharmaceuticals; D015899:Tomography, Emission-Computed, Single-Photon
chemical_list: D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; C059659:technetium Tc 99m bicisate; D003545:Cysteine