Individuals with depression experience more negative imagery and less
vivid positive imagery, and the late positive potential (LPP) is
considered as a viable biomarker for negative attentional and memory
biases in depression; however, the LPP response to emotional imagery in
depressed individuals remains unclear. This study aims to investigate
neural response to emotional imagery in depressed individuals. ERPs were
recorded from 40 depressed participants and 44 healthy controls during
the encoding-imagery task. Depressed participants scored significantly
lower in the valence rating of sad and neutral imagery compared to
healthy participants. Importantly, the LPP amplitudes to sad imagery in
depressed participants were significantly larger than healthy controls,
particularly in the middle (800-1,400 ms) and late time
windows(1,400-2,000 ms). Furthermore, depressed individuals exhibited
significantly higher LPP amplitudes for sad imagery compared to happy
imagery, whereas healthy participants showed the opposite pattern. The
present study provides evidence that depressed individuals display
abnormal electrophysiological reactivity to sad imagery, which offers a
new perspective for understanding the mechanisms underlying depression.