Brain Activity Elicited by Negative Stimuli in Males with Recurrent and Bipolar Depression

Abstract

Aim: To study the characteristics of brain activity in male patients with recurrent and bipolar depression. Design: This was a comparative controlled non-randomized experimental clinical study. Materials and Methods: 59 male patients took part in this study before their medication started: 30 with bipolar and 29 with unipolar (recurrent) depression. Control group consisted of 27 healthy male volunteers. All investigated persons were aged 20 to 59 years. The participants had to sort photos of people and animals, of which 80 were neutral images and 80 showed angry/aggressive people or animals. Simple patterns (cues) were displayed two seconds prior to the pictures, and their relationship was not explained. A 128-channel EEG was recorded and brain responses were analyzed in 0–700 ms from cue onset. Differences between the neutral and emotional conditions (emotional modulation, EM) were statistically evaluated. Results: All components in this study (P100, N170/VPP, P200, P380, and LPC/LPP) in various degrees showed EM dependent on the group and on the type of threatening stimuli. Topography of EM for N170/VPP in all groups and both types of stimuli was quite similar. None of the components unambiguously distinguished between the controls and nosographically different depressions. Conclusion: Our results show that in the study of affective disorders and the search for markers for diagnosis, it is necessary not only to take into account the gender of patients, but also to use various cognitive tasks when recording EEG, and also to consider a set of neurophysiological parameters. Keywords: emotional modulation, electroencephalogram, recurrent depression, bipolar depression, visual evoked potentials.