Table 1.

Sex differences of electrophysiological properties of medium spiny neurons across striatal subregions in rats.

Electrophysiological property	Developmental stage	Caudate-putamen	Nucleus accumbens core	Nucleus accumbens shell
Intrinsic excitability	Prepubertal	F > M	F = M	F = M
	Adult	?d	Cycle determines sex differencea	?
Excitatory synaptic input	Prepubertal	F = M	F > Mb	F = M
	Adult	?	Cycle determines sex differencea	?c

Gray fill indicates sex and/or cycle dependent differences. Inequality signs indicate relative differences between sexes. “?” indicates complex or no evidence.

^aEstrous cycle stage determined directionality of sex difference and difference between female estrous stages. Gonadectomy eliminates sex differences.

^bThis sex difference has been shown to be organized by estradiol during masculinization window.

^cExamination of synapse properties shows divergent evidence of sex differences in non-stressed animals, but an electrophysiological approach in adult animals has not yet been done to our knowledge (as reviewed by Cao et al., 2018b). The adult nucleus accumbens shell exhibits variable sex differences, likely indicating interactions with other environmental influences such as stress (i.e., Brancato et al., 2017).

^dIn adult caudate-putamen, estrous-cycle induced differences in select rat medium spiny neuron action potential generation rates have been reported in vivo, but the underlying cellular electrophysiological mechanisms are not yet documented.