title: Fronto-temporal alterations within the first 200 ms during an attentional task distinguish major depression, non-clinical participants with depressed mood and healthy controls: a potential biomarker?
abstract: Attentional impairment in depression is a cardinal feature of depression and has been proposed as a candidate endophenotype for major depressive disorder. Event-related potentials (ERPs) elicited by oddball signal detection tasks provide objective markers of selective stimulus processing, and are pertinent endophenotypic markers for depression. While previous studies have sought to determine objective markers for attentional impairment in depression, evidence is inconsistent and may involve heterogeneity in relatively small samples. Here, we brought together oddball ERP recording with source localization of neural correlates of selective attention in outpatients with major depressive disorder (MDD; n = 78) and participants with depressed mood (PDM; n = 127) relative to healthy controls (CTL; n = 116). The key finding was a dimensional exaggeration of the P200 (140-270 ms) to both target (signal) and non-target (noise) stimuli, most pronounced in MDD, followed by PDM, relative to CTL. This exaggeration was coupled with slower and more variable response times, suggesting that neural systems are attempting to compensate for a difficulty in discriminating signal from noise. P200 alterations were localised to limbic (hippocampal), temporal and ventral prefrontal regions, key components of the signal detection network. A subsequent reduction and delay in the P300 was also revealed for MDD indicating that the pronounced lack of discrimination in clinical depression may also lead to impaired stimulus evaluation. This P200 increase in depression could provide a potential mechanism for the attentional impairment frequently observed in depression and consequent alterations in the P300 may differentiate clinically significant depression.
authors.affiliation: Brain Dynamics Centre, Westmead Millennium Institute, Westmead Hospital, Australia. info@brain-dynamics.net
authors.forename: Andrew H
authors.initials: AH
authors.lastname: Kemp
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Hopkinson
authors.forename: Daniel F
authors.initials: DF
authors.lastname: Hermens
authors.forename: Donald L
authors.initials: DL
authors.lastname: Rowe
authors.forename: Alexander L
authors.initials: AL
authors.lastname: Sumich
authors.forename: C Richard
authors.initials: CR
authors.lastname: Clark
authors.forename: Wilhelmus
authors.initials: W
authors.lastname: Drinkenburg
authors.forename: Nadia
authors.initials: N
authors.lastname: Abdi
authors.forename: Rebecca
authors.initials: R
authors.lastname: Penrose
authors.forename: Alexander
authors.initials: A
authors.lastname: McFarlane
authors.forename: Philip
authors.initials: P
authors.lastname: Boyce
authors.forename: Evian
authors.initials: E
authors.lastname: Gordon
authors.forename: Leanne M
authors.initials: LM
authors.lastname: Williams
mesh_terms: D001288:Attention / Q000502:physiology*; D015415:Biomarkers / Q000032:analysis; D002540:Cerebral Cortex / Q000503:physiopathology*; D003863:Depression / Q000175:diagnosis / Q000503:physiopathology*; D003865:Major Depressive Disorder / Q000175:diagnosis / Q000503:physiopathology*; D003937:Diagnosis, Differential; D006624:Hippocampus / Q000503:physiopathology; D009483:Neuropsychological Tests; D011237:Predictive Value of Tests; D017397:Prefrontal Cortex / Q000503:physiopathology; D011597:Psychomotor Performance / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology*; D013702:Temporal Lobe / Q000503:physiopathology; D013997:Time Factors
chemical_list: D015415:Biomarkers