Calcium-based synaptic and structural plasticity link pathological activity to synaptic reorganization in Parkinson's...

Area of Science:

• Computational neuroscience
• Neurobiology
• Systems neuroscience

Background:

• Parkinson's disease (PD) motor deficits are linked to dopaminergic neuronal loss.
• Dopamine depletion (DD) in the basal ganglia (BG) causes altered neural activity, including beta oscillations and bursting.
• Synaptic reorganization is a key feature following dopamine depletion.

Purpose of the Study:

• To computationally model DD-induced neural activity and synaptic reorganization in the BG subcircuit.
• To investigate the role of calcium-dependent plasticity in network changes.
• To understand how indirect pathway striatal projection neuron (iMSN) hyperactivity influences synaptic connectivity.

Main Methods:

• Developed a computational model of the subthalamic nucleus and globus pallidus externus.
• Incorporated calcium-dependent synaptic and structural plasticity mechanisms.
• Simulated dopamine depletion and analyzed resulting network dynamics and topology changes.

Main Results:

• Model demonstrated that iMSN hyperactivity can induce synaptic changes mirroring PD animal models.
• Synaptic reorganization was shown to result from homeostatic, calcium-based synaptic changes.
• These changes are triggered by hyperactivity in iMSNs following striatal dopamine depletion.

Conclusions:

• Synaptic reorganization in the BG following dopamine depletion is driven by homeostatic plasticity.
• This structural plasticity acts as a compensatory mechanism for elevated iMSN input.
• Compensatory mechanisms may fail if iMSN and cortical inputs exhibit significant bursting activity.