INDIVIDUAL BALANCE OF DEFENSIVE AND APPETITIVE MOTIVATIONAL SYSTEMS OF THE BRAIN AS A LIKELY NEUROPHYSIOLOGICAL ENDOPHENOTYPE OF DEPRESSION IN THE METRIC OF COGNITIVE EVOKED POTENTIALS

Abstract

The aim of the study was to investigate the characteristics of the individual balance of the activity of brain defensive and reinforcing systems in patients with major depressive disorder. Material and methods. In 41 patients with major depressive disorder and 32 healthy subjects, we investigated visual evoked potentials in the emotional Oddball paradigm in perception of high and low arousal motivational signals of reward and threat. Results and discussion. It was established that reduced amplitude of the neuronal response in the perception of high arousal motivational signals of reward and, in a less degree, threat, is associated with an indicator of the clinical severity of depression. It supports the model of emotion context insensitivity in depression. However, a more pronounced reduce in the neuronal response to stimuli of reward may indicate a prevailing deficiency of the reinforcement system. Thus, the late positive potential magnitude of visual evoked potentials for high arousal motivational signals of reward and threat can be viewed as a promising objective neurobiological marker for monitoring the dynamics of the disturbed individual balance of the defensive and reinforcing brain systems in major depressive disorder patients which can become an important tool of personalized prevention and treatment strategy.

Keywords

• major depressive disorder
• visual evoked potentials
• late positive potential
• individual balance of motivational systems
• neurophysiological endophenotype