Facial expression and imagery in depression: an electromyographic study

Area of Science:

• Psychology
• Neuroscience
• Psychophysiology

Background:

• Facial electromyography (EMG) can detect discrete muscle activity patterns during emotional imagery.
• Previous studies suggest depressed individuals exhibit attenuated facial EMG responses, particularly during happy imagery.

Purpose of the Study:

• To investigate facial EMG patterns during self-generated happy and sad imagery in depressed versus non-depressed subjects.
• To compare the effects of "think" versus "reexperiencing feelings" instructions on facial EMG.
• To determine if "think" instructions are more sensitive in differentiating between depressed and non-depressed individuals.

Main Methods:

• 12 depressed and 12 matched normal subjects generated happy and sad imagery.
• Facial EMG was recorded from corrugator, zygomatic major, depressor anguli oris, and mentalis muscles.
• Two conditions were used: "think" about imagery and "reexperiencing the feelings".

Main Results:

• Facial muscle sites reliably differentiated between happy and sad imagery.
• Self-regulating feelings produced greater EMG differences than "think" instructions.
• Depressed subjects showed significantly attenuated facial EMG, especially for happy imagery under "think" instructions.

Conclusions:

• Facial EMG effectively assesses mood states in both normal and clinical populations.
• Facial muscle patterning plays a role in the subjective experience of emotion.
• "Think" instructions may be a sensitive indicator for detecting emotional processing differences in depression.