TY - JOUR
T1 - Altered prefrontal cortex activity during working memory task in Bipolar Disorder
T2 - A functional Magnetic Resonance Imaging study in euthymic bipolar I and II patients
AU - Dell'osso, Bernardo
AU - Cinnante, Claudia
AU - Di Giorgio, Annabella
AU - Cremaschi, Laura
AU - Palazzo, M. Carlotta
AU - Cristoffanini, Marta
AU - Fazio, Leonardo
AU - Dobrea, Cristina
AU - Avignone, Sabrina
AU - Triulzi, Fabio
AU - Bertolino, Alessandro
AU - Altamura, A. Carlo
PY - 2015/6/12
Y1 - 2015/6/12
N2 - Abstract Background Working memory (WM) deficits are among the most frequently impaired cognitive domains in patients with Bipolar Disorder (BD), being considered promising cognitive endophenotype of the disorder. However, the related neurobiological correlates still deserve further investigation. The present study was aimed to explore whether dorsolateral prefrontal cortex (DLPFC) activity during WM processing was abnormal in euthymic bipolar patients and may represent a potential trait-related phenotype associated with the disorder. Methods Using 3 Tesla functional Magnetic Resonance Imaging (3T fMRI), we studied 28 euthymic bipolar patients (15 BDI and 13 BDII), and 27 healthy controls (HCs), matched for a series of socio-demographic variables, while performing the N-back task for WM assessment. Results We found that euthymic bipolar patients showed increased right middle frontal gyrus engagement compared with HCs (FWE-corrected p=1×10-3), regardless of WM load, and in spite of similar WM behavioral performance between groups. In particular, BDI patients had greater BOLD signal change compared to HCs (post-hoc Tukey HSD, p=1×10-3), while BDII patients expressed an intermediate pattern of activation between BDI patients and HCs. No other significant effects were detected in the corrected whole-brain analysis. Limitations Sample size, cross-sectional assessment and potential influence of some clinical variables. Conclusions Results provide direct evidence of a primary physiological abnormality in DLPFC function in BDI and II, even in the absence of behavioral differences with HCs. Such exaggerated fMRI response suggests inefficient WM processing in prefrontal circuitry, and further studies are warranted to investigate whether the dysfunction is related to the genetic risk for the disorder.
AB - Abstract Background Working memory (WM) deficits are among the most frequently impaired cognitive domains in patients with Bipolar Disorder (BD), being considered promising cognitive endophenotype of the disorder. However, the related neurobiological correlates still deserve further investigation. The present study was aimed to explore whether dorsolateral prefrontal cortex (DLPFC) activity during WM processing was abnormal in euthymic bipolar patients and may represent a potential trait-related phenotype associated with the disorder. Methods Using 3 Tesla functional Magnetic Resonance Imaging (3T fMRI), we studied 28 euthymic bipolar patients (15 BDI and 13 BDII), and 27 healthy controls (HCs), matched for a series of socio-demographic variables, while performing the N-back task for WM assessment. Results We found that euthymic bipolar patients showed increased right middle frontal gyrus engagement compared with HCs (FWE-corrected p=1×10-3), regardless of WM load, and in spite of similar WM behavioral performance between groups. In particular, BDI patients had greater BOLD signal change compared to HCs (post-hoc Tukey HSD, p=1×10-3), while BDII patients expressed an intermediate pattern of activation between BDI patients and HCs. No other significant effects were detected in the corrected whole-brain analysis. Limitations Sample size, cross-sectional assessment and potential influence of some clinical variables. Conclusions Results provide direct evidence of a primary physiological abnormality in DLPFC function in BDI and II, even in the absence of behavioral differences with HCs. Such exaggerated fMRI response suggests inefficient WM processing in prefrontal circuitry, and further studies are warranted to investigate whether the dysfunction is related to the genetic risk for the disorder.
KW - Bipolar Disorder (BD)
KW - Dorsolateral prefrontal cortex (DLPFC)
KW - functional Magnetic Resonance Imaging (fMRI)
KW - Working memory (WM)
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U2 - 10.1016/j.jad.2015.05.026
DO - 10.1016/j.jad.2015.05.026
M3 - Article
C2 - 26074021
AN - SCOPUS:84930946914
VL - 184
SP - 116
EP - 122
JO - Journal of Affective Disorders
JF - Journal of Affective Disorders
SN - 0165-0327
M1 - 7462
ER -