Veinante, P. | bioRxiv Science

bioRxiv2022

The basolateral amygdala-anterior cingulate pathway contributes to depression and its comorbidity with chronic pain

While depression and chronic pain are frequently comorbid, underlying neuronal circuits, and their relevance for the understanding of psychopathology, remain poorly defined. Here we show in mice that hyperactivity of the neuronal pathway linking the basolateral amygdala to the anterior cingulate cortex is essential for chronic pain-induced depression. In naive animals, we demonstrate that activation of this pathway is sufficient to trigger depressive-like behaviors, as well as transcriptomic alterations that recapitulate core molecular features of depression in the human brain. These alterations notably impact gene modules related to myelination and the oligodendrocyte lineage. Among these, we show that Sema4a, a hub gene significantly upregulated in both mice and humans in the context of altered mood, is necessary for the emergence of depressive-like behaviors. Overall, these results place the BLA-ACC pathway at the core of pain and depression comorbidity, and unravel the role of impaired myelination and Sema4a in mood control.

neuroscience↗

bioRxiv2017

Cell-type specific parallel circuits in the bed nucleus of the stria terminalis and the central nucleus of the amygdala of the mouse

The central extended amygdala (EAc) is a forebrain macrosystem which has been widely implicated in fear, anxiety and pain. Its two key structures, the lateral bed nucleus of the stria terminalis (STL) and the central nucleus of amygdala (CeA), share similar mesoscale connectivity. However, it is not known whether they also share similar cell-specific neuronal circuits. We addressed this question using tract-tracing and immunofluorescence to reveal the connectivity of two neuronal populations expressing either protein kinase C delta (PKC{delta}) or somatostatin (SOM). PKC{delta} and SOM are expressed predominantly in the dorsal part of STL (STLD) and in the lateral/capsular parts of CeA (CeL/C). We found that, in both STLD and CeL/C, PKC{delta}+ cells are the main recipient of extra-EAc inputs from the external lateral part of the parabrachial nucleus (LPBE), while SOM+ cells are the sources of long-range projections to extra-EAc targets, including LPBE and periaqueductal gray. PKC{delta}+ cells can also integrate inputs from posterior basolateral nucleus of amygdala or insular cortex. Within EAc, PKC{delta}+, but not SOM+ neurons, serve as the major source of projections to the ventral part of STL and to the medial part of CeA. However, both cell types mediate interconnections between STLD and CeL/C. These results unveil the pivotal positions of PKC{delta} and SOM neurons in organizing parallel cell-specific neuronal circuits of CeA and STL, which further support the idea of EAc as a structural and functional macrostructure.

neuroscience↗