Descending projections from the central nucleus of the amygdala synapse with different neuron types in the nucleus of the solitary tract.

This article focuses on the neural connectivity and synaptic organization of central nucleus of the amygdala (CeA) projections to the rostral gustatory portion of the nucleus of the solitary tract (rNST) in mice. Using electron microscopy and transsynaptic viral tracing in transgenic mice, the study demonstrates that CeA axon terminals in the rNST are GABAergic and primarily synapse onto non-GABAergic neurons expressing markers such as Phox2b, glutamate, and calretinin. These rNST neurons receiving CeA input are distributed across multiple subdivisions and project mainly to the ipsilateral parvocellular reticular formation and parabrachial nucleus, implicating CeA input in modulating both ascending gustatory signals and orosensory motor functions like licking, mastication, and salivation. The findings provide anatomical evidence for descending neuromodulatory pathways from the CeA that influence taste processing and ingestive behavior.