# A molecularly defined basalo-prefrontal-thalamic circuit regulates sensory and affective dimensions of pain in male mice

## TL;DR

This study identifies a brain circuit involving the prefrontal cortex and thalamus that controls pain in male mice, offering new insights for chronic pain treatment.

## Contribution

The study reveals a novel HDB→mPFCFoxp2→thalamus circuit and its cholinergic signaling role in pain modulation.

## Key findings

- mPFC Foxp2+ neurons are deactivated in acute and chronic pain in male mice.
- Activation of mPFC Foxp2+ neurons reduces pain sensitivity, while their inactivation increases it.
- Cholinergic signaling in mPFC Foxp2+ neurons influences pain through nicotinic acetylcholine receptors.

## Abstract

Both the medial prefrontal cortex (mPFC) and thalamus have been implicated in pain regulation. However, the roles of the mPFC-thalamus connection in pain and how the mPFC modulates nociceptive processing remain unclear. Here, we show that the mPFC neurons projecting to thalamus, marked by Foxp2 expression, are deactivated in both acute and chronic pain in male mice. Persistent inactivation of the mPFC Foxp2+ neurons enhances nociceptive sensitivity, while their activation alleviates multiple aspects of pain. Circuit-specific manipulations revealed that the projections to parataenial nucleus, mediodorsal and ventromedial thalamus differentially modulate sensory and affective pain. Additionally, the mPFC Foxp2+ neurons receive cholinergic input from the basal forebrain, particularly the horizontal diagonal band (HDB). Notably, activation of the α4β2-containing nicotinic acetylcholine receptor in mPFC exerts antinociceptive effects in Foxp2+ neuron-dependent manner. Together, our study defines an HDB→mPFCFoxp2→thalamus circuit essential for sensory and affective pain modulation and underscores the therapeutic potential of targeting mPFC cholinergic signaling in chronic pain management.

This study presents an HDB (horizontal diagonal band) – mPFC (medial prefrontal cortex) – thalamus circuit and the cholinergic signaling in mPFC Foxp2+ neurons in modulating sensory and affective pain in male mice.