P100 in major depressive disorder and healthy controls: An emotion-processing task

Area of Science:

• Neuroscience
• Psychiatry
• Cognitive Science

Background:

• Major Depressive Disorder (MDD) is characterized by altered emotion processing, including reduced positive reactivity and heightened negative sensitivity.
• The precise biological mechanisms underlying these emotional and cognitive biases in MDD remain unclear.
• Event-related potentials offer a window into the neural dynamics of emotion processing.

Purpose of the Study:

• To investigate event-related P100 components associated with emotion processing in individuals with MDD compared to healthy controls (HCS).
• To explore how neural processing of emotional stimuli differs between MDD patients and HCS.

Main Methods:

• Electroencephalography (EEG) with a 64-channel system was used to record P100 amplitudes and latencies.
• Participants included 87 MDD patients and 100 HCS, assessed on responses to emotional stimuli (positive, negative, neutral) varying in arousal.
• P100 measures were analyzed across left and right hemisphere electrodes.

Main Results:

• Healthy controls (HCS) displayed greater right-hemisphere P100 amplitudes, indicating right-hemispheric dominance, which was absent in MDD patients.
• P100 amplitudes were higher in women than men and correlated with higher state anxiety.
• Medication status influenced P100: unmedicated individuals had higher amplitudes, while SSRI use correlated with shorter latencies and SNRI use with longer latencies.

Conclusions:

• MDD is associated with diminished hemispheric lateralization in early visual processing, unlike the right-hemispheric dominance observed in HCS.
• No significant effects of stimulus valence or arousal on P100 were found.
• Gender, anxiety levels, and psychotropic medication significantly modulate P100 measures, indicating subtle alterations in visual processing in MDD.