PBN-PVT projection modulates negative affective states in mice

Long-lasting negative affections dampen enthusiasm for life, and dealing with negative affective states is essential for individual survival. The parabrachial nucleus (PBN) and the thalamic paraventricular nucleus (PVT) are critical for modulating affective states in mice. However, the functional role of the PBN-PVT projection in modulating affective states remains elusive. Here, we show that the PBN neurons send dense projection fibers to the PVT and form direct excitatory synapses with the PVT neurons. Activation of the PBN-PVT projection or PVT-projecting PBN neurons induces robust anxiety-like, aversion-like, and fear-like behaviors without affecting nociceptive behaviors. Inhibition of the PBN-PVT projection or PVT-projecting PBN neurons reduces fear-like and aversion-like behaviors. Furthermore, the PVT neurons innervated by the PBN are activated by aversive stimulation, and activation of PBN-PVT projection enhances the neuronal activity of PVT neurons in response to the aversive stimulus. Activation of these downstream PVT neurons induces anxiety-like behavior behaviors. Thus, our study indicates that the PBN-PVT projection modulates negative affective states in mice.