A genome editing technique based on the clustered regularly interspaced short palindromic repeats (CRISPR)associated endonuclease Cas9 enables efficient modification of genes in various cell types, including neurons. However, neuronal ensembles even in the same brain region are not anatomically or functionally uniform but divide into distinct subpopulations. Such heterogeneity requires gene editing in specific neuronal populations. We developed a CRISPR-SaCas9 system-based technique, and its combined application with anterograde/ retrograde AAV vectors and activity-dependent cell-labeling techniques achieved projection-and function-specific gene editing in the rat brain. As a proof-of-principle application, we knocked down the cbp (CREB-binding protein), a sample target gene, in specific neuronal subpopulations in the medial prefrontal cortex, and demonstrated the significance of the projection-and function-specific CRISPR-SaCas9 system in revealing neuronal and circuit basis of memory. The high efficiency and specificity of our projection-and function-specific CRISPR-SaCas9 system could be widely applied in neural circuitry studies. Development of a CRISPR-SaCas9 system for projection-and function-specific gene editing in the rat brain. Sci. Adv. 6, eaay6687 (2020).

The coverage of events was predominantly positive toward tobacco control. However, media reports could better support tobacco control efforts if they did a better job at provoking an emotional response to the harms of tobacco use and promoting a sense among smokers that they can succeed in quitting smoking.

Social memory enables one to recognize and distinguish specific individuals. It is fundamental to social behaviors that can be mediated by the oxytocin receptor (OXTR), such as forming relationships. We investigated the molecular regulation and function of OXTR in animal behavior involving social memory. We found that Ser 261 in OXTR was phosphorylated by protein kinase D1 (PKD1). Neuronal Ca 2+ signaling and behavior analyses revealed that rats expressing a mutated form of OXTR that cannot be phosphorylated at this residue (OXTR S261A) in the medial amygdala (MeA) exhibited impaired long-term social memory (LTSM). Blocking the phosphorylation of wild-type OXTR in the MeA using an interfering peptide in rats or through conditional knockout of Pkd1 in mice reduced social memory retention, whereas expression of a phosphomimetic mutant of OXTR rescued it. In HEK293A cells, the PKD1-mediated phosphorylation of OXTR promoted its binding to G q protein and, in turn, OXTR-mediated phosphorylation of PKD1, indicating a positive feedback loop. In addition, OXTR with a single-nucleotide polymorphism found in humans (rs200362197), which has a mutation in the conserved recognition region in the PKD1 phosphorylation site, showed impaired activation and signaling in vitro and in HEK293A cells similar to that of the S216A mutant. Our findings describe a phosphoregulatory loop for OXTR and its critical role in social behavior that might be further explored in associated disorders.

With the shifting role of placebos, there is a need to develop animal models of placebo analgesia and elucidate the mechanisms underlying the effect. In the present study, male Sprague-Dawley rats with chronic inflammatory pain caused by complete Freund's adjuvant (CFA) underwent a series of conditioning procedures, in which morphine was associated with different cues, but they failed to induce placebo analgesia. Then, conditioning with the conditioned place preference apparatus successfully induced analgesic expectancy and placebo analgesia in naı ¨ve rats but only induced analgesic expectancy and no analgesic effect in CFA rats. Subsequently, we found enhanced c-fos expression in the nucleus accumbens and reduced expression in the anterior cingulate cortex in naı ¨ve rats while c-fos expression in the anterior cingulate cortex in CFA rats was not altered. In summary, the behavioral conditioning model demonstrated the difficulty of establishing a placebo analgesia model in rats with a pathological condition.