Manipulating Reward Sensitivity Using Reward Circuit-Targeted Transcranial Magnetic Stimulation

Area of Science:

• Neuroscience
• Psychiatry
• Neuromodulation

Background:

• The reward circuit is crucial for motivation and learning.
• Dysregulation of this circuit is a hallmark of anhedonic depression.
• Noninvasive methods targeting the reward circuit could treat anhedonia.

Purpose of the Study:

• To investigate a novel transcranial magnetic stimulation (TMS) intervention for modulating the reward circuit.
• To assess the efficacy of targeting the rostromedial prefrontal cortex (rmPFC) with intermittent theta burst stimulation (iTBS).

Main Methods:

• A crossover controlled study involving 35 healthy individuals.
• iTBS was applied to either the rmPFC or a control site.
• Reward circuit targets were identified using functional MRI (fMRI) connectivity with the ventral striatum.
• Reward function was assessed using fMRI and the reward positivity event-related potential.

Main Results:

• rmPFC iTBS significantly enhanced the reward positivity compared to control iTBS.
• The enhancement was greater in individuals with lower baseline reward function.
• Efficacy depended on both rmPFC-ventral striatum connectivity and precise TMS targeting.

Conclusions:

• The study demonstrates that rmPFC iTBS can effectively modulate the reward circuit.
• Modulation capacity is linked to individual reward circuit function.
• This research is a foundational step towards novel noninvasive treatments for reward circuit disorders.