Ross, S. E. | bioRxiv Science

bioRxiv2019

A labeled-line for cold from the periphery to the parabrachial nucleus

Spinal projection neurons are a major pathway through which somatic stimuli are conveyed to the brain. However, the manner in which this information is coded is poorly understood. Here, we report the identification of a modality-selective spinoparabrachial (SPB) neuron subtype with unique properties. Specifically, we find that cold-selective SPB neurons are differentiated by selective afferent input, reduced neuropeptide sensitivity, distinct physiological properties, small soma size, and low basal drive. In addition, optogenetic experiments reveal that cold-selective SPB neurons are distinctive with respect to their connectivity, with little to no input from either Pdyn or Nos1 inhibitory interneurons. Together, these data define a neural substrate supporting a labeled-line for cold from the periphery to the brain.

neuroscience↗

bioRxiv2019

Divergent neural pathways emanating from the lateral parabrachial nucleus mediate distinct components of the pain response

The lateral parabrachial nucleus (lPBN) is a major target of spinal projection neurons conveying nociceptive input into supraspinal structures. However, the functional role of distinct lPBN efferents for diverse nocifensive responses have remained largely uncharacterized. Here, we show that two populations of efferent neurons from different regions of the lPBN collateralize to distinct targets. Activation of efferent projections to the ventromedial hypothalamus (VMH) or lateral periaqueductal gray (lPAG) drive escape behaviors, whereas the activation of lPBN efferents to the bed nucleus stria terminalis (BNST) or central amygdala (CEA) generates an aversive memory. Finally, we provide evidence that dynorphin expressing neurons span cytoarchitecturally distinct domains of the lPBN to coordinate these distinct aspects of the nocifensive response.\n\nHIGHLIGHTSSpatially segregated neurons in the lPBN collateralize to distinct targets.\n\nDistinct output pathways give rise to separate aspects of the pain response.\n\nDynorphin neurons within the lPBN convey noxious information across subdivisions.\n\neTOC BLURBChiang et al. reveal that neurons in spatially segregated regions of the lateral parabrachial nucleus collateralize to distinct targets, and that activation of distinct efferents gives rise to separate components of the nocifensive response.

neuroscience↗