title: Sex differences in myelin-associated protein levels within and density of projections between the orbital frontal cortex and dorsal striatum of adult rats: implications for inhibitory control.
abstract: Impulsive actions and decisions often lead to undesirable outcomes. Lesion and neuroimaging studies have revealed that the orbital frontal cortex (OFC) and dorsal striatum (dSTR) play key roles in inhibitory control. It has been proposed that greater OFC input into the dSTR reflects enhanced top-down cognitive control and less impulsive responding. We previously reported a sex difference in inhibitory control, such that female rats make fewer impulsive errors than do male rats. The goal of the present study was to investigate differences in the OFC and dSTR of young adult male and female rats. In Experiment 1, we measured levels of two myelin-associated proteins, myelin basic protein (MBP) and myelin proteolipid protein (PLP), in the OFC and dSTR. Western blot data revealed that females had significantly higher levels of both MBP and PLP in the OFC but similar levels in the dSTR as compared to males. In Experiment 2, we infused the anterograde tracer, biotinylated dextran amine (BDA), into the OFC and measured the density of BDA in the dSTR. BDA was visualized using histochemistry followed by light microscopy imaging and densitometry analysis. Density of BDA in the dSTR was significantly greater in females as compared to males indicating that the projections from the OFC to dSTR may be greater in females as compared to males. Our results suggest a potential neuroanatomical sex difference that may contribute to the reported differences in inhibitory control levels of male and female rats.
authors.affiliation: Department of Psychology, Tulane University, New Orleans, LA 70118, USA. Electronic address: daniel.bayless@ucsf.edu.
authors.forename: D W
authors.initials: DW
authors.lastname: Bayless
authors.affiliation: Department of Psychology, Tulane University, New Orleans, LA 70118, USA; Neuroscience Program, Tulane University, New Orleans, LA 70118, USA. Electronic address: jmdaniel@tulane.edu.
authors.forename: J M
authors.initials: JM
authors.lastname: Daniel
mesh_terms: D000818:Animals; D001710:Biotin / Q000031:analogs & derivatives; D015153:Blotting, Western; D003342:Corpus Striatum / Q000033:anatomy & histology* / Q000502:physiology*; D003911:Dextrans; D056344:Executive Function / Q000502:physiology; D005260:Female; D005625:Frontal Lobe / Q000033:anatomy & histology* / Q000502:physiology*; D007266:Inhibition, Psychological; D008297:Male; D008853:Microscopy; D004676:Myelin Basic Protein / Q000378:metabolism*; D018991:Myelin Proteolipid Protein / Q000378:metabolism; D056347:Neuroanatomical Tract-Tracing Techniques; D056325:Neuronal Tract-Tracers; D020318:Rats, Long-Evans; D012727:Sex Characteristics
chemical_list: D003911:Dextrans; C436006:Mbp protein, rat; D004676:Myelin Basic Protein; D018991:Myelin Proteolipid Protein; D056325:Neuronal Tract-Tracers; C489071:Plp1 protein, rat; C076397:biotinylated dextran amine; D001710:Biotin
keywords: anterograde tracer; inhibitory control; myelin; orbital frontal cortex; sex difference; striatum