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

Huerta Grande, Córdoba

Congreso; IRCN Second Joint Meeting of the Argentine Society for Neurosciences (SAN) and the Argentine Workshop in Neurosciences (TAN); 2010

Bipolar disorder is a psychiatric diagnosis describing mood disorders which alternates episodes of mania (abnormally elevated levels of energy, cognitive abilities and mood) with depression. Although bipolar patients have cognitive impairments even in euthymia, patients report an increased perceptual sensitivity during mania (linked in some subgroup of patients to creativity) and shadowing of perception during depression.We hypothesized that the threshold of conscious access (i.e. the strength of a stimulus to access consciousness) may vary with the different phases of bipolar disorder. We measured conscious threshold using an iterative masking procedure. 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 separate conscious and executive function processing, we measured the threshold in four different attentional control mechanisms.  We observed a main effect of phase on the threshold when comparing across groups:  1) thresholds were higher for patients in the depressive phase than for controls, 2) thresholds were lower for patients in the mania phase than for controls and 3) thresholds were slightly higher for patients in the euthimic phase than for controls.