Neuronal coding of implicit emotion categories in the subcallosal cortex in patients with depression

Area of Science:

• Neuroscience
• Affective Science
• Computational Psychiatry

Background:

• The subcallosal cortex (SCC) is crucial for emotional processing and implicated in mood disorders like depression.
• Previous neuroimaging studies suggest the SCC processes negative valence, arousal, or specific emotion categories, but its precise role remains unclear.
• Understanding SCC function is vital for developing targeted depression therapies.

Purpose of the Study:

• To elucidate the functional role of single neurons in the subcallosal cortex (SCC) during emotional perception.
• To determine if SCC neuronal activity is driven by emotional valence, arousal, or specific emotion categories.
• To investigate the SCC's contribution to affective valuation and emotion categorization.

Main Methods:

• Recorded single neuron activity in the SCC of 15 human subjects undergoing deep brain stimulation for depression.
• Subjects viewed emotionally evocative images categorized by valence (pleasantness) and arousal.
• Analyzed neuronal responses in relation to image categories, valence, and arousal.

Main Results:

• The majority of responsive SCC neurons were modulated by specific emotion categories, not solely by valence or arousal.
• These neurons responded to both positive and negative emotion categories.
• A significant majority of emotion-category-selective neurons showed a preference for negatively valenced emotional content.

Conclusions:

• Single SCC neuron activity reflects automatic affective valuation and implicit emotion categorization of visual stimuli.
• The predominance of negative affective signals in the SCC suggests a role in negative emotional processing bias.
• Depression therapies targeting SCC activity may be effective by down-regulating this negative processing bias.