Ventral pallidum regulates the default mode network, controlling transitions between internally and externally guided...

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Behavioral Neuroscience

Background:

• Daily activities involve shifting between automatic, internally guided actions and externally focused tasks.
• These behavioral transitions are linked to the default mode network (DMN), a brain network active during internal thought.

Purpose of the Study:

• To investigate the role of the ventral pallidum (VP), a key DMN node, in modulating task switching.
• To examine how optogenetic manipulation of VP affects the ability to switch between internally and externally guided behaviors in rats.

Main Methods:

• Rats were trained on an auditory discrimination task requiring shifts in behavioral guidance.
• Optogenetic techniques were used to selectively excite or inhibit neuronal activity in the VP.
• Behavioral performance, including task acquisition and attention to external stimuli, was assessed.

Main Results:

• VP excitation impaired the acquisition of the external-stimulus-guided task, suggesting a persistent DMN state and reduced attention to external cues.
• VP inhibition facilitated task acquisition, enabling rats to disengage from internally focused states and adapt to changing environmental contingencies.
• These findings indicate that VP activity is crucial for flexible switching between internally and externally directed behaviors.

Conclusions:

• The ventral pallidum (VP) plays a critical, moment-to-moment role in regulating the default mode network (DMN).
• VP activity deterministically influences the brain's ability to transition between internally driven automatized behaviors and externally guided actions.
• Modulating VP offers a potential mechanism for controlling cognitive flexibility and attention allocation.