According to recent findings activation of anterior cingulate co
rtex (ACC) is related to detecting cognitive conflict. This
conflict related activation elicits autonomic responses which can be assessed by psychophysiological measures such as
heart rate variability calculated as beat to beat R-R interv
als (RRI). Recent findings in neuroscience also suggest that
cognitive conflict is related to specific nonlinear chaotic changes of the signal generated by neural systems. The present
study used Stroop word-color test as an experimental approach to psychophysiological study of cognitive conflict in
connection with RRI measurement, psychometric measurement of limbic irritability (LSCL-33), depression (BDI-II)
and calculation of largest Lyapunov exponents in nonlinear data analysis of RRI time series. Significant correlation 0.61
between largest Lyapunov exponents and LSCL-33 found in this study indicate that a defect of neural inhibition during
conflicting Stroop task is closely related to
limbic irritability. Because limbic irritability is probably closely related to
epileptiform abnormalities in the temporolimbic structures, this result might represent useful instrument for indication
of anticonvulsant treatment in depressive patients who are resistant to antidepressant medication.
We tested the hypothesis considering the role of hypothalamic-pituitary-thyroid axis (HPT), L-triiodothyronine (L-T3) uptake into erythrocytes, and the role of membrane lipids in the development and treatment of affective disorders. Changes in kinetic parameters (Vmax, maximal velocity and KM, apparent Michaelis constant) of L-T3 uptake into red blood cells (RBCs) and changes in membrane fluidity in a group of 24 patients with major depression were measured before treatment and after 1 month of treatment with citalopram. Parameters Vmax and KM, as well as membrane microviscosity, were significantly increased in depressed patients both before and after treatment in comparison with healthy subjects. We concluded that the function of the membrane transporter for L-T3 in RBC is changed in depression. This change is probably connected with alteration of membrane fluidity and/or transporter–lipid interactions. We did not find any normalization of the measured parameters after 1 month of treatment. The results show the importance of composition and physical properties of the lipid bilayer for transmembrane transport of L-T3 and support the hypothesis that the HPT axis is in depression.