Multiphasic modulation of cholinergic interneurons by nigrostriatal afferents

Area of Science:

• Neuroscience
• Neurobiology
• Synaptic Transmission

Background:

• Striatal motor and learning functions depend on dopamine neurons and cholinergic interneurons (CINs).
• Dopamine neurons and CINs exhibit opposing firing patterns to sensory stimuli.
• The mechanism of dopamine's modulation of CIN firing, crucial for sensory responses, is unclear.

Purpose of the Study:

• To elucidate the mechanisms by which midbrain dopamine neurons modulate striatal cholinergic interneuron (CIN) firing.
• To investigate the role of phasic dopaminergic activity in the CIN 'pause-rebound' sensory response.

Main Methods:

• Utilized a mouse striatal slice preparation.
• Employed optogenetics, electrophysiology, and pharmacological techniques.
• Investigated phasic activation of nigrostriatal afferents.

Main Results:

• Phasic nigrostriatal afferent activation induced a pause-rebound response in CINs.
• Synaptically released dopamine inhibited CINs via dopamine D2 receptors.
• An unidentified transmitter mediated the delayed excitation of CINs.

Conclusions:

• Midbrain dopamine neurons indirectly regulate striatal output by controlling cholinergic tone.
• Phasic dopaminergic activity contributes to the CIN pause-rebound response to salient stimuli.
• Findings deepen understanding of dopamine's role in striatal circuit modulation for motor control and learning.