Synaptic Regulation of a Thalamocortical Circuit Controls Depression-Related Behavior

Publication date: 22 August 2017
Source:Cell Reports, Volume 20, Issue 8
Author(s): Oliver H. Miller, Andreas Bruns, Imen Ben Ammar, Thomas Mueggler, Benjamin J. Hall
The NMDA receptor (NMDAR) antagonist ketamine elicits a long-lasting antidepressant response in patients with treatment-resistant depression. Understanding how antagonism of NMDARs alters synapse and circuit function is pivotal to developing circuit-based therapies for depression. Using virally induced gene deletion, ex vivo optogenetic-assisted circuit analysis, and in vivo chemogenetics and fMRI, we assessed the role of NMDARs in the medial prefrontal cortex (mPFC) in controlling depression-related behavior in mice. We demonstrate that post-developmental genetic deletion of the NMDAR subunit GluN2B from pyramidal neurons in the mPFC enhances connectivity between the mPFC and limbic thalamus, but not the ventral hippocampus, and reduces depression-like behavior. Using intersectional chemogenetics, we show that activation of this thalamocortical circuit is sufficient to elicit a decrease in despair-like behavior. Our findings reveal that GluN2B exerts input-specific control of pyramidal neuron innervation and identify a medial dorsal thalamus (MDT)→mPFC circuit that controls depression-like behavior.

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In these experiments, Miller et al. show that GluN2B-containing NMDARs are enriched at synapses between the medial dorsal thalamus and medial prefrontal cortex. They also show that post-developmental deletion of these receptors in the mPFC enhances synaptic connectivity and that direct activation of this circuit in vivo drives strong antidepressant-like behavior in mice.


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