A Viral Labelling Study of Spinal Trigeminal Nucleus Caudalis Projection Neurons Targeting the Parabrachial Nucleus.

Projection neurons (PNs) in the Spinal Trigeminal Nucleus Caudalis (Sp5C) relay orofacial nociceptive information to higher brain regions such as the thalamus and the parabrachial nucleus (PBN). Our understanding of Sp5C PN organisation and function has advanced less than the parallel spinal cord output system despite their corresponding roles for transmission of nociceptive signals from the orofacial region and body respectively. Viral vectors are an established approach for studying circuit connectivity in the nervous system, but different serotypes are known to produce variable results across circuits.