Depressive status modulates hippocampal-cortical dynamics during acute nicotine use

Area of Science:

• Neuroscience
• Psychiatry
• Addiction Medicine

Background:

• Nicotine use disorder (NUD) treatment response varies, possibly due to differences in neural circuits, especially with co-occurring depression.
• Understanding these neural differences is crucial for developing effective, personalized NUD treatments.

Purpose of the Study:

• To investigate real-time neural dynamics during nicotine inhalation in individuals with and without depression.
• To explore how depressive status modulates hippocampal activity and hippocampal-cortical connectivity in response to nicotine.

Main Methods:

• Simultaneous hippocampal recordings using responsive neurostimulation (RNS) electrodes and scalp electroencephalography (EEG) were performed in two chronic nicotine users (one with depression, one without).
• Analysis focused on oscillatory activity and hippocampal-cortical connectivity, correlated with mood and craving states.

Main Results:

• Oscillatory activity correlated with mood in the non-depressed individual but showed attenuated or reversed patterns in the depressed individual, indicating reduced reward responsiveness.
• Both participants exhibited reduced alpha hippocampal-cortical connectivity post-nicotine, suggesting a shift towards reward and relief processing.

Conclusions:

• Depressive status may significantly modulate neural dynamics and hippocampal-cortical connectivity during nicotine use.
• Findings support a network-based framework for NUD and highlight the potential for identifying neurophysiological subtypes to guide personalized treatment strategies.