Examining the Effects of MrgprB4+ Neuron Optogenetic Activation on Reward Behavior and Pup Vocalizations

Student Classification


Faculty Mentor

Dr. Ishmail Abdus-Saboor



Document Type


Publication Date

Fall 2019


Gentle stroking from a family member or intimate partner can be rewarding. C-low threshold mechanoreceptors (C-LTMRs) are sensory neurons that respond to stroking of the skin at rates that are deemed pleasurable and are therefore implicated in soothing, comforting touch in humans. MrgprB4+ neurons in mice are a molecular subclass of CLTMR. Previous studies have demonstrated that chemogenetic activation of MrgprB4+ neurons promoted

place preference in mice. However, chemogenetic activation results in simultaneous, body-wide activation lasting tens of minutes to hours, which is not physiologically or ecologically relevant. Therefore, the aim of this study is to assess the effects of focally activating MrgprB4+ neurons on various behaviors (i.e. place preference and pup vocalization) through optogenetic activation. The optogenetic activation technique better mimics stroking, as it is focally and temporally restricted. In this study, we used cre-lox technology to generate mice that would allow us to optogenetically activate MrgprB4+ neurons by shining a laser onto the back skin during both an acute and conditioned place preference paradigm, and an acute maternal separation paradigm. Our results revealed that optogenetic activation of MrgprB4+ neurons did not promote place preference or reduce pup vocalizations. Overall, the results demonstrate that the current optogenetic technical paradigm to study rewarding behavior with MrgprB4+ neuron activation is not sufficient to evoke rewarding or positive valence behavior. In future studies, we can modify our optogenetic activation paradigm or target different molecular classes of CLTMRs in the context of reward behaviors.

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