Shines and shadows of perception: the threshold for access to consciousness fluctuates with phases of Bipolar Disorder

MARTÍN GRAZIANO; HERNÁN ANLLÓ; DIEGO MARTINO; JULIA TEITELBAUM; SERGIO STREJILEVICH; MARIANO SIGMAN

Congreso; 9th International Conference on Bipolar Disorder; 2011

Introduction: In bipolar disorders, cognitive performance varies with mood fluctuations, normally with an overall decrement. Interestingly, patients report increased perceptual sensitivity during early stages of mania-hypomania (often linked to increased creativity) previous to the detrimental effects on attention and memory, and shadowing of perception during depression. To quantify this, we investigated if threshold of conscious access (i.e. the strength of a stimulus to access consciousness) increases during depression and decreases during mania. Methods:  We measured conscious threshold using an iterative masking procedure in BD patients at different phases of the disorder, and in euthymic patients and healthy controls. As the temporal interval between the stimulus and the mask decreases, stimulus visibility decreases following a sigmoidal function from which a threshold can be derived. To disentangle conscious and executive function processing, we measured the threshold in four different attentional control mechanisms. We selected subjects who displayed a regular behaviour during the entire test. Results: We observed a main effect of phase on the threshold across 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). Thresholds were higher for depressed patients than for other groups (Post-hoc analysis, Bonferroni test p<0.05) with no significative difference between controls, euthymic and manic patients (p>0.05) despite a slighter decreased between controls and maniac patients. Correlations between YMRS and MADRS scores with threshold were positive for the latter (r, 0.47, p=0.06) with a negative tendency for the former (r, -0.25, p=0.32). Despite the main effect of 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 increased conscious threshold during depression and a negative tendency during mania. Thus, mood fluctuations could modulate consciousness´ states (even positively in early stages of mania) independently from attention.