@article{willett_will_hauser_dorris_cao_meitzen_2016, title={No Evidence for Sex Differences in the Electrophysiological Properties and Excitatory Synaptic Input onto Nucleus Accumbens Shell Medium Spiny Neurons}, volume={3}, ISSN={["2373-2822"]}, DOI={10.1523/eneuro.0147-15.2016}, abstractNote={Visual Overview Sex differences exist in how the brain regulates motivated behavior and reward, both in normal and pathological contexts. Investigations into the underlying neural mechanisms have targeted the striatal brain regions, including the dorsal striatum and nucleus accumbens core and shell. Sex differences exist in how the brain regulates motivated behavior and reward, both in normal and pathological contexts. Investigations into the underlying neural mechanisms have targeted the striatal brain regions, including the dorsal striatum and nucleus accumbens core and shell. These investigations yield accumulating evidence of sexually different electrophysiological properties, excitatory synaptic input, and sensitivity to neuromodulator/hormone action in select striatal regions both before and after puberty. It is unknown whether the electrical properties of neurons in the nucleus accumbens shell differ by sex, and whether sex differences in excitatory synaptic input are present before puberty. To test the hypothesis that these properties differ by sex, we performed whole-cell patch-clamp recordings on male and female medium spiny neurons (MSNs) in acute brain slices obtained from prepubertal rat nucleus accumbens shell. We analyzed passive and active electrophysiological properties, and miniature EPSCs (mEPSCs). No sex differences were detected; this includes those properties, such as intrinsic excitability, action potential afterhyperpolarization, threshold, and mEPSC frequency, that have been found to differ by sex in other striatal regions and/or developmental periods. These findings indicate that, unlike other striatal brain regions, the electrophysiological properties of nucleus accumbens shell MSNs do not differ by sex. Overall, it appears that sex differences in striatal function, including motivated behavior and reward, are likely mediated by other factors and striatal regions.}, number={1}, journal={ENEURO}, author={Willett, Jaime A. and Will, Tyler and Hauser, Caitlin A. and Dorris, David M. and Cao, Jinyan and Meitzen, John}, year={2016} }
 @article{dorris_cao_willett_hauser_meitzen_2015, title={Intrinsic excitability varies by sex in prepubertal striatal medium spiny neurons}, volume={113}, ISSN={["1522-1598"]}, DOI={10.1152/jn.00687.2014}, abstractNote={ Sex differences in neuron electrophysiological properties were traditionally associated with brain regions directly involved in reproduction in adult, postpubertal animals. There is growing acknowledgement that sex differences can exist in other developmental periods and brain regions as well. This includes the dorsal striatum (caudate/putamen), which shows robust sex differences in gene expression, neuromodulator action (including dopamine and 17β-estradiol), and relevant sensorimotor behaviors and pathologies such as the responsiveness to drugs of abuse. Here we examine whether these sex differences extend to striatal neuron electrophysiology. We test the hypothesis that passive and active medium spiny neuron (MSN) electrophysiological properties in prepubertal rat dorsal striatum differ by sex. We made whole cell recordings from male and females MSNs from acute brain slices. The slope of the evoked firing rate to current injection curve was increased in MSNs recorded from females compared with males. The initial action potential firing rate was increased in MSNs recorded from females compared with males. Action potential after-hyperpolarization peak was decreased, and threshold was hyperpolarized in MSNs recorded from females compared with males. No sex differences in passive electrophysiological properties or miniature excitatory synaptic currents were detected. These findings indicate that MSN excitability is increased in prepubertal females compared with males, providing a new mechanism that potentially contributes to generating sex differences in striatal-mediated processes. Broadly, these findings demonstrate that sex differences in neuron electrophysiological properties can exist prepuberty in brain regions not directly related to reproduction. }, number={3}, journal={JOURNAL OF NEUROPHYSIOLOGY}, author={Dorris, David M. and Cao, Jinyan and Willett, Jaime A. and Hauser, Caitlin A. and Meitzen, John}, year={2015}, month={Feb}, pages={720–729} }