Paired Electrical Pulse Trains for Controlling Connectivity in Emotion-Related Brain Circuitry

Area of Science:

• Neuroscience
• Psychiatric Research
• Brain-Computer Interface

Background:

• Current neurostimulation therapies for psychiatric disorders show limited clinical efficacy.
• This limitation may stem from a disconnect between therapeutic approaches and underlying brain circuit mechanisms.
• Mental disorders are often characterized by disrupted communication within distributed brain networks.

Purpose of the Study:

• To develop a novel electrical stimulation method for modifying narrow-frequency-band (theta, 5-8 Hz) neural coherence and synaptic strength.
• To investigate the effects of this method on the infralimbic cortex (IL) to basolateral amygdala (BLA) circuit, crucial for fear regulation.
• To explore the potential of targeted connectivity modulation as a therapeutic strategy for psychiatric conditions.

Main Methods:

• Developed a precise electrical stimulation technique using paired 6 Hz pulse trains.
• Applied stimulation to the IL and BLA with controlled inter-train time lags.
• Measured changes in IL-BLA circuit coherence and synaptic strength.

Main Results:

• The paired pulse stimulation induced long-lasting changes in synaptic strength.
• A transient enhancement in IL-BLA neural coherence was observed.
• This coherence enhancement was direction-specific (IL-to-BLA) and contingent upon a precise 180° (83 ms) relative lag between stimulation trains.

Conclusions:

• The developed method effectively modulates specific aspects of brain circuit connectivity, including coherence and synaptic strength.
• This technique provides a valuable tool for investigating the relationship between brain network dynamics and behaviors like fear regulation.
• The findings suggest a potential new approach for developing more effective neurostimulation therapies by targeting network communication.