title: Preparatory attention after lesions to the lateral or orbital prefrontal cortex--an event-related potentials study.
abstract: The prefrontal cortex (PFC) plays a central role in preparatory and anticipatory attentional processes. To investigate whether subregions of the PFC play differential roles in these processes we investigated the effect of focal lesions to either lateral prefrontal (lateral PFC; n=11) or orbitofrontal cortex (OFC; n=13) on the contingent negative variation (CNV), an electrophysiological index of preparatory brain processes. The CNV was studied using a Go/NoGo delayed response task where an auditory S1 signaled whether or not an upcoming visual S2 was a Go or a NoGo stimulus. Neither early (500-1000 ms) nor late (3200-3700 ms) phase Go trial CNV amplitude was reduced for any of the patient groups in comparison to controls. However, the lateral PFC group showed enhanced Go trial early CNV and reduced late CNV Go/NoGo differentiation. These data suggests that normal orienting and evaluation as reflected by the CNV is intact after OFC lesions. The enhanced early CNV after lateral PFC damage may be due to failure in inhibition and the reduced late CNV difference wave confirms a deficit in preparatory attention after damage to this frontal subregion.
authors.affiliation: Department of Psychosomatic Medicine, Division of Surgery and Clinical Neuroscience, Oslo University Hospital - Rikshospitalet, Norway. ifunderu@ous-hf.no
authors.forename: Ingrid
authors.initials: I
authors.lastname: Funderud
authors.forename: Marianne
authors.initials: M
authors.lastname: Løvstad
authors.forename: Magnus
authors.initials: M
authors.lastname: Lindgren
authors.forename: Tor
authors.initials: T
authors.lastname: Endestad
authors.forename: Paulina
authors.initials: P
authors.lastname: Due-Tønnessen
authors.forename: Torstein R
authors.initials: TR
authors.lastname: Meling
authors.forename: Robert T
authors.initials: RT
authors.lastname: Knight
authors.forename: Anne-Kristin
authors.initials: AK
authors.lastname: Solbakk
mesh_terms: D000328:Adult; D001288:Attention / Q000502:physiology*; D003265:Contingent Negative Variation / Q000502:physiology*; D004569:Electroencephalography; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017397:Prefrontal Cortex / Q000293:injuries* / Q000503:physiopathology*
keywords: Contingent negative variation (CNV); Event-related potentials; Lateral prefrontal cortex; Orbitofrontal cortex