title: Prefrontal contributions to delayed spatial and object alternation: a positron emission tomography study.
abstract: Delayed alternation tasks are frequently used as probes of frontal lobe functioning. To clarify the neural substrates of delayed alternation performance in humans, the authors measured regional cerebral blood flow with H2(15)O positron emission tomography in healthy subjects as they performed delayed spatial and object alternation. Consistent with the monkey lesion literature, increased dorsolateral prefrontal activity emerged during delayed spatial alternation but not delayed object alternation, whereas orbitofrontal activations emerged in both alternation tasks. The possible cognitive processes contributing to the orbitofrontal and dorsolateral prefrontal involvement in delayed alternation are discussed. Additional activations localized to several nonfrontal regions suggest caution in interpreting alternation deficits in patients as strictly reflecting frontal lobe impairment.
authors.affiliation: Department of Psychology, Vanderbilt University, USA.
authors.forename: David H
authors.initials: DH
authors.lastname: Zald
authors.forename: Clayton
authors.initials: C
authors.lastname: Curtis
authors.forename: Bradley S
authors.initials: BS
authors.lastname: Folley
authors.forename: José V
authors.initials: JV
authors.lastname: Pardo
mesh_terms: D000328:Adult; D005260:Female; D005556:Form Perception / Q000502:physiology*; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D010104:Oxygen Radioisotopes; D010775:Photic Stimulation; D017397:Prefrontal Cortex / Q000000981:diagnostic imaging* / Q000502:physiology*; D013028:Space Perception / Q000502:physiology*; D014055:Tomography, Emission-Computed
chemical_list: D010104:Oxygen Radioisotopes