title: Dissociating the neural mechanisms of distance and spatial reference frames.
abstract: This study investigated if the neural mechanisms involved in processing distance (near and far) and frame of reference (egocentric and allocentric) can be dissociated. 36 participants completed a conjunction visual search task using either an egocentric (deciding if the target was to their left or right) or an allocentric (deciding if the target was to the left or right of a reference object) frame. Both tasks were performed in near (57 cm) and far (171 cm) space conditions. Participants were separated into three groups, and each received transcranial magnetic stimulation (TMS) to a different site; right posterior parietal cortex (rPPC), right ventral occipital cortex (rVO), or right frontal eye field (rFEF) in addition to sham TMS. The results show that rFEF is critical in the processing of each search at each distance whereas, contrary to previous detection results, TMS over rVO did not affect performance for any condition. TMS over rPPC revealed that specialised egocentric processing in the parietal cortex does not generalise to far space, providing evidence of a separation of the reference frame/distance conflation in the literature.
authors.affiliation: Cognitive Neuroscience Research Unit, Wolfson Research Institute, Durham University, Queen's Campus, Stockton-on-Tees, TS17 6BH, UK. Electronic address: a.r.lane@durham.ac.uk.
authors.forename: Alison R
authors.initials: AR
authors.lastname: Lane
authors.affiliation: Cognitive Neuroscience Research Unit, Wolfson Research Institute, Durham University, Queen's Campus, Stockton-on-Tees, TS17 6BH, UK. Electronic address: k.l.ball@durham.ac.uk.
authors.forename: Keira
authors.initials: K
authors.lastname: Ball
authors.affiliation: Cognitive Neuroscience Research Unit, Wolfson Research Institute, Durham University, Queen's Campus, Stockton-on-Tees, TS17 6BH, UK. Electronic address: amanda.ellison@durham.ac.uk.
authors.forename: Amanda
authors.initials: A
authors.lastname: Ellison
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001931:Brain Mapping; D004215:Distance Perception / Q000502:physiology*; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009778:Occipital Lobe / Q000502:physiology*; D010296:Parietal Lobe / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D013028:Space Perception / Q000502:physiology*; D050781:Transcranial Magnetic Stimulation; D055815:Young Adult
keywords: Frontal eye fields; Parietal cortex; Spatial processing; Transcranial magnetic stimulation; Ventral occipital; Visual search