Rethinking the external globus pallidus and information flow in cortico-basal ganglia-thalamic circuits

Area of Science:

• Neuroscience
• Computational Neuroscience
• Systems Neuroscience

Background:

• The external globus pallidus (GPe) has been traditionally viewed as a passive component within the indirect pathway of the cortico-basal ganglia-thalamic (CBGT) circuit.
• This model suggested a unidirectional flow of information, where GPe primarily relays signals from the striatum to inhibit downstream targets.

Approach:

• This study re-evaluates the role of the GPe by considering recent findings on its cellular properties, connectivity, and behavioral functions.
• A new circuit-level perspective is proposed, highlighting the GPe's capacity for bidirectional information processing.

Key Points:

• The GPe is strategically positioned to relay both ascending and descending control signals within the basal ganglia.
• Bidirectional information flow in the GPe integrates reactive and proactive control mechanisms essential for action selection.
• Emerging evidence supports the GPe as a dynamic hub, crucial for regulating behavior.

Conclusions:

• The external globus pallidus (GPe) functions as a central hub in the cortico-basal ganglia-thalamic (CBGT) circuit.
• It plays a critical role in integrating diverse control signals through bidirectional information flow.
• This integration enables sophisticated regulation of behavior, particularly during action selection.