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

Area of Science:

• Neuroscience
• Systems Neuroscience
• Computational Neuroscience

Background:

• The external globus pallidus (GPe) has traditionally been considered a passive component of the indirect pathway in the cortico-basal ganglia-thalamic (CBGT) circuit.
• This view posited a one-way flow of information, where striatal signals amplified thalamic suppression via GPe inhibition.

Purpose of the Study:

• To re-evaluate the functional role of the GPe based on recent findings regarding its cellular and network properties.
• To explore the GPe's potential as a central hub for bidirectional information flow within the CBGT circuit.

Main Methods:

• Review and synthesis of emerging research on GPe cellular complexity and connectivity.
• Circuit-level analysis to understand information processing within the basal ganglia.

Main Results:

• The GPe is strategically positioned to relay both ascending and descending control signals within the basal ganglia.
• Bidirectional information flow through the GPe integrates reactive and proactive control for action selection.
• Evidence supports the GPe as a central hub in the CBGT circuit.

Conclusions:

• The GPe's role extends beyond a simple relay, acting as a critical integration center.
• The GPe facilitates bidirectional communication, essential for regulating behavior and action selection.
• This revised understanding highlights the GPe's significance in complex motor control and decision-making processes.