Shines and shadows of perception: the threshold for acces to consciousness fluctuates with phases of bipolar disorder.

GRAZIANO M., ANLLO H., MARTINO D.J., TEITELBAUM J., STREJILEVICH S.A., SIGMAN M.

Conferencia; Ninth International Conference on Bipolar Disorder; 2011

Introduction: In bipolar disorders, cognitive performance varieswith mood fluctuations, normally with an overall decrement.Interestingly, patients report increased perceptual sensitivity duringearly stages of mania-hypomania (often linked to increasedcreativity) previous to the detrimental e!ects on attention andmemory, and shadowing of perception during depression. Toquantify this, we investigated if threshold of conscious access (i.e.the strength of a stimulus to access consciousness) increases duringdepression and decreases during mania.Methods: We measured conscious threshold using an iterativemasking procedure in BD patients at di!erent phases of thedisorder, and in euthymic patients and healthy controls. As thetemporal interval between the stimulus and the mask decreases,stimulus visibility decreases following a sigmoidal function fromwhich a threshold can be derived. To disentangle conscious andexecutive function processing, we measured the threshold in fourdi!erent attentional control mechanisms. We selected subjects whodisplayed a regular behaviour during the entire test.Results: We observed a main e!ect of phase on the thresholdacross groups (Two-Factor ANOVA, F3,111 = 4.06, p < 0.01;Mean values: conscious threshold controls, 57 ± 8 ms; euthymia,55±7 ms; depression, 84±13 ms; mania, 50±2 ms). Thresholdswere higher for depressed patients than for other groups (Post-hocanalysis, Bonferroni test p<0.05) with no significative differencebetween controls, euthymic and manic patients (p>0.05) despite aslighter decreased between controls and maniac patients.Correlations between YMRS and MADRS scores with thresholdwere positive for the latter (r, 0.47, p=0.06) with a negativetendency for the former (r, )0.25, p=0.32). Despite the main effectof attentional condition across groups (F3,111 = 6.91, p << 0.01),we didn’t observe an interaction effect between them (F9,111 =0.27, p = 0.98).Discussion: The present provides initial evidence of an increasedconscious threshold during depression and a negative tendencyduring mania. Thus, mood fluctuations could modulateconsciousness¢ states (even positively in early stages of mania)independently from attention.