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Introduction In the dopamine system, the mesolimbic pathway, including the dorsal striatum, underlies the reinforcing properties of tobacco smoking, and the mesocortical pathway, including the dorsolateral prefrontal cortex (dlPFC), is critical for cognitive functioning. Dysregulated dopamine signaling has been linked to drug-seeking behaviors and cognitive deficits. The dorsal striatum and dlPFC are structurally and functionally connected and are key regions for cognitive functioning. We recently showed that people who smoke have lower dlPFC dopamine (D2/3R) receptor availability than people who do not, which is related to poorer cognitive function. Aims and Methods The goal of this study was to examine the same brain-behavior relationship in the dorsal striatum. Twenty-nine (18 males) recently abstinent people who smoke and 29 sex-matched healthy controls participated in 2 same-day [11C]-(+)-PHNO positron emission tomography scans before and after amphetamine administration to provoke dopamine release. D2/3R availability (binding potential; BP ND) and amphetamine-induced dopamine release (%Δ BP ND) were calculated. Cognition (verbal learning and memory) was assessed with the CogState computerized battery. Results There were no group differences in baseline BP ND. People who smoke have a smaller magnitude %Δ BP ND in dorsal putamen than healthy controls (p  = .022). People who smoke perform worse on immediate (p  = .035) and delayed (p  = .011) recall than healthy controls. In all people, lower dorsal putamen BP ND was associated with worse immediate (p  = .006) and delayed recall (p  = .049), and lower %Δ BP ND was related to worse delayed recall (p  = .022). Conclusions Lower dorsal putamen D2/3R availability and function are associated with disruptions in cognitive function that may underlie difficulty with resisting smoking. Implications This study directly relates dopamine imaging outcomes in the dorsal striatum to cognitive function in recently abstinent people who smoke cigarettes and healthy controls. The current work included a well-characterized subject sample in terms of demographics, smoking characteristics, and a validated neurocognitive test of verbal learning and memory. The findings of this study extend previous literature relating dopamine imaging outcomes to cognition in recently abstinent people who smoke and people who do not smoke, expanding our understanding of brain-behavior relationships. [ABSTRACT FROM AUTHOR]

Introduction Tobacco smoking is a major public health burden. The mesocortical dopamine system—including the dorsolateral prefrontal cortex (dlPFC)—plays an important role in cognitive function. Dysregulated dopamine signaling in dlPFC is associated with cognitive deficits such as impairments in attention, learning, working memory, and inhibitory control. We recently showed that dlPFC dopamine D2/3-type receptor (D2R) availability was significantly lower in people who smoke than in healthy-controls and that dlPFC amphetamine-induced dopamine release was lower in females who smoke relative to males who smoke and female healthy-controls. However, we did not examine whether the smoking-related dopamine deficits were related to cognitive deficits. Aims and Methods The goal of this study was to relate dopamine metrics to cognitive performance in people who smoke and healthy-controls. In total 24 (12 female) people who smoke cigarettes and 25 sex- and age-matched healthy-controls participated in two same-day [11C]FLB457 positron emission tomography (PET) scans before and after amphetamine administration. Two outcome measures were calculated—D2R availability (non-displaceable binding potential; BP ND ) and amphetamine-induced dopamine release (%Δ BP ND ). Cognition (verbal learning and memory) was assessed with a computerized test from the CogState battery (International Shopping List). Results People who smoke had significantly worse immediate (p =.04) and delayed (p =.03) recall than healthy-controls. Multiple linear regression revealed that for people who smoke only, lower D2R availability was associated with worse immediate (p =.04) and delayed (p <.001) recall. %Δ BP ND was not significantly related to task performance. Conclusion This study demonstrated that lower dlPFC D2R availability in people who smoke is associated with disruptions in cognitive function that may underlie difficulty with resisting smoking. Implications This is the first study to directly relate dopamine metrics in the prefrontal cortex to cognitive function in people who smoke cigarettes compared to healthy-controls. The current work included a well-characterized subject sample with regards to demographic and smoking variables, as well as a validated neurocognitive test of verbal learning and memory. The findings of this study extend previous literature by relating dopamine metrics to cognition in people who smoke, providing a better understanding of brain-behavior relationships. [ABSTRACT FROM AUTHOR]

Background: There has been an ongoing need to compare and combine the results of new PET imaging studies conducted with [11C]raclopride with older data. This typically means harmonizing data across different scanners. Previous harmonization studies have utilized either phantoms or human subjects, but the use of both phantoms and humans in one harmonization study is not common. The purpose herein was (1) to use phantom images to develop an inter-scanner harmonization technique and (2) to test the harmonization technique in human subjects. Methods: To develop the harmonization technique (Experiment 1), the Iida brain phantom was filled with F-18 solution and scanned on the two scanners in question (HRRT, HR+, Siemens/CTI). Phantom images were used to determine the optimal isotropic Gaussian filter to harmonize HRRT and HR+ images. To evaluate the harmonization on human images (Experiment 2), inter-scanner variability was calculated using [11C]raclopride scans of 3 human subjects on both the HRRT and HR+ using percent difference (PD) in striatal non-displaceable binding potential (BPND) between HR+ and HRRT (with and without Gaussian smoothing). Finally, (Experiment 3), PDT/RT was calculated for test–retest (T/RT) variability of striatal BPND for 8 human subjects scanned twice on the HR+. Results: Experiment 1 identified the optimal filter as a Gaussian with a 4.5 mm FWHM. Experiment 2 resulted in 13.9% PD for unfiltered HRRT and 3.71% for HRRT filtered with 4.5 mm. Experiment 3 yielded 5.24% PDT/RT for HR+. Conclusions: The PD results show that the variability of harmonized HRRT is less than the T/RT variability of the HR+. The harmonization technique makes it possible for BPND estimates from the HRRT to be compared to (and/or combined with) those from the HR+ without adding to overall variability. Our approach is applicable to all pairs of scanners still in service. [ABSTRACT FROM AUTHOR]

Objectives: Concurrent substance use disorder (SUD) and posttraumatic stress disorder (PTSD) occur at high rates and are typically associated with poor treatment outcomes in both sexes. However, women have a propensity to cope with increased negative affect via substance use in comparison to men; thus, it is important to elucidate the sex-specific bidirectional relationships between SUD and PTSD to improve our understanding of concurrent SUD/PTSD in men and women. Methods: Using data from the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC-Wave 3; n = 36,309), the present study evaluated the impact of sex on the relationship between past-year SUDs (new, remitted, ongoing), including alcohol and drug use, and retrospective transitions in new vs. absent and ongoing vs. remitted diagnoses of PTSD. Additionally, the impact of sex was explored in models examining past year PTSD (new, remitted, ongoing) and retrospective transitions in new vs. absent and ongoing vs. remitted diagnosis of SUDs. Diagnostic transitions were based on retrospective reporting. Results: Results indicated that new, remitted, and ongoing SUDs increase the likelihood of new PTSD diagnoses (OR range = 2.53–8.11; p < 0.05). Among individuals with ongoing drug use disorders (DUD), there were greater odds of ongoing PTSD (OR = 2.10, p < 0.01). When examining the relationship reciprocally, new, remitted, and ongoing PTSD increased the likelihood of new SUDs (OR range = 2.50–8.22; p < 0.05), and ongoing PTSD increased the likelihood of ongoing SUD and DUD (OR = 1.40, 1.70, respectively; p < 0.05). Sex-specific analyses revealed that the relationship between PTSD and SUDs varies between sexes, particularly among women. For instance, women with new PTSD had higher odds of SUDs, and women with ongoing PTSD were almost 2.5 times more likely to have an ongoing DUD. Women with a new PTSD diagnosis were more likely to be diagnosed with a new SUD (OR = 3.27) and an ongoing DUD (OR = 3.08). Conclusions: Results indicate a bidirectional relationship between PTSD and SUD that is in many instances larger in women. Thus, illustrating potential sex-specific differences in underlying mechanisms implicated in SUD/PTSD, warranting additional research. [ABSTRACT FROM AUTHOR]

Sex-/gender-related differences in cognitive control and how they relate to addictions may inform novel treatment options. Cognitive control, including Stroop performance, has been linked to addictions and treatment outcomes. The extent to which women and men with cocaine use disorder (CUD) show brain and behavioral differences relating to Stroop performance has not been previously studied. We examined sex-related differences in Stroop-related brain connectivity in female and male CUD and healthy-comparison (HC) subjects. 40 individuals with CUD (20 female) and 40 HC (20 female) subjects matched on age, race, and ethnicity completed an fMRI Stroop task. Intrinsic connectivity distribution (ICD) and mean-adjusted ICD analyses were conducted to identify differences related to sex and diagnostic group. Stroop task performance was also considered. Behavioral results confirmed a Stroop effect. A main effect of diagnostic group indicated that the CUD versus HC group showed lower connectivity in the prefrontal cortex, frontal gyrus, cingulate gyrus, precuneus, cerebellum, and somatosensory, visual, and auditory areas. An exploratory main effect of sex suggested that males may show relatively lower connectivity than females in the cerebellum and brainstem, although connectivity was largely similar across sexes. Intrinsic connectivity during cognitive control varied by diagnostic group and possibly by sex. The findings suggest that interventions targeting cognitive control in CUD should consider sex. • Functional connectivity has previously been associated with cognitive control (Stroop performance). • Subjects displayed a 'Stroop effect' (slower reaction time to incongruent trials). • People with versus without CUD showed less frontal, parietal, and limbic connectivity. • Exploratory findings show lower cerebellar and brainstem connectivity in males than females. • Findings support cognitive control processes vary by group and possibly sex. [ABSTRACT FROM AUTHOR]

Introduction: Sex differences exist in tobacco smoking. Women have greater difficulty quitting smoking than men. Tobacco smoking is driven by the reinforcing effects of nicotine, the primary addictive component in cigarettes. Nicotine binds to nicotinic acetylcholine receptors, facilitating dopamine release in striatal and cortical brain regions. Dysregulated dopamine D 2/3 receptor signaling in the dorsolateral prefrontal cortex (dlPFC) is associated with cognitive deficits such as impairments in attention, learning, and inhibitory control that impede quit attempts. Sex steroid hormones, such as estradiol and progesterone, influence drug-taking behaviors, through dopaminergic actions, suggesting that their influence may explain sex differences in tobacco smoking. The goal of this study was to relate dlPFC dopamine metrics to sex steroid hormone levels in people who smoke and healthy controls., Methods: Twenty-four (12 women) people who smoke cigarettes and 25 sex- and age-matched controls participated in two same-day [ 11 C]FLB457 positron emission tomography scans, one before and one after amphetamine administration. D 2 R availability ( BP ND ) at baseline and after amphetamine administration was calculated. On the same day, plasma samples were collected for the analysis of sex steroid hormone levels: estradiol, progesterone, and free testosterone., Results: Women who smoke had trending lower levels of estradiol than their sex-matched counterparts. Men who smoke had higher levels of estradiol and trending higher levels of free testosterone than their sex-matched counterparts. Among women only, lower estradiol levels were significantly associated with lower pre-amphetamine dlPFC BP ND ., Discussion/conclusion: This study demonstrated that lower estradiol levels are associated with lower dlPFC D 2 R availability in women which may underlie difficulty resisting smoking., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Zakiniaeiz, Gueorguieva, Peltier, Verplaetse, Roberts, McKee and Cosgrove.)

Preclinical research is fundamental for the advancement of biomedical sciences and enhancing healthcare. Considering sex differences in all studies throughout the entire biomedical research pipeline is necessary to adequately inform clinical research and improve health outcomes. However, there is a paucity of information to date on sex differences in preclinical work. As of 2009, most (about 80 percent) rodent studies across 10 fields of biology were still conducted with only male animals. In 2016, the National Institutes of Health implemented a policy aimed to address this concern by requiring the consideration of sex as a biological variable in preclinical research grant applications. This perspective piece aims to (1) provide a brief history of female inclusion in biomedical research, (2) describe the importance of studying sex differences, (3) explain possible reasons for opposition of female inclusion, and (4) present potential additional solutions to reduce sex bias in preclinical research.