---

Background and purpose: Methamphetamine (METH) is one of the most powerful drugs that leads to many cognitive and behavioral side effects such as anxiety. On the other hand, studies have shown that ovarian hormones such as estrogen and progesterone have neuroprotective effects on a wide range of cognitive and behavioral disorders. The aim of this study was to investigate the role of estrogen and progesterone on anxiety-like behaviors, body temperature, brain edema, and neuronal death induced by neurotoxic regimen of methamphetamine.
Materials and methods: This study was performed in 48 ovariectomized rats divided into six groups including: control, METH (6mg / kg), vehicle (sesame oil), METH + estrogen (1mg / kg), METH + progesterone (8mg / kg), and METH + estrogen + progesterone. Body temperature and anxiety-like behaviors were investigated, then, the animals were killed and brain tissues were harvested to evaluate brain edema and neuronal death in hippocampal CA1.
Results: Body temperature, brain water content, motor activity, and anxiety-related behaviors significantly increased in animals that received METH (P<0.001), but, treatment with estrogen and progesterone attenuated motor activity, and anxiety-related behaviors induced by METH. Brain edema, body temperature, and neuronal cell death in hippocampal CA1 area partially decreased in METH+estrogen and METH + progesterone groups.
Conclusion: This study suggests that ovarian hormones such as estrogen and progesterone are effective in improving behavioral deficits and neuronal death induced by METH in ovariectomized rats.
 

---

Background and purpose: Insomnia is a common sleep disorder with negative consequences such as decreased quality of life. In this study, the effect of sleep deprivation on memory in both young and older adults was investigated using functional magnetic resonance imaging (fMRI).
Materials and methods: In this retrospective study, fMRI data of 40 healthy subjects (17 young and 23 older people) who had a one-month sleep deprivation period (during the experiment they woke up three hours earlier than usual) were obtained. Then, pre-processing was done to remove artifacts and noise. Finally, data processing was completed in order to extract the brain activity map focusing on brain areas related to memory.
Results: Findings showed that the brain activity of most areas are reduced due to insomnia. In the young group, 17 functional connections were obtained at the beginning of the study which decreased to only one connection after the insomnia period. In older adults there were seven connections at the beginning of the study that decreased to four after the insomnia period (P< 0.05).
Conclusion: Brain map analysis, including connections and activity levels of memory-related areas, showed that sleep deprivation affects the brains of young and old people. Our findings can pave the way for future studies to understand the effect of insomnia on memory and brain.

---

Background and purpose: Methamphetamine is one of the stimulant drugs that leads to the occurrence of cognitive and behavioral dysfunctions. Among the disorders that occur after methamphetamine abuse are learning and memory disorders as well as social interactions and anxiety. On the other hand, the function of sex steroids in the development of brain regions involved in reproduction has been the subject of extensive research over the years. In this context, testosterone plays an important role in neuronal and glial organization in prenatal and postnatal periods. Recent studies showed the effect of sex hormones on the nervous system and highlight the brain as a main target tissue for androgens. On the other hand, studies have shown that testosterone has neuroprotective effects against cognitive and behavioral disorders. Clinical manifestations of testosterone-related brain changes include cognitive impairments such as reduced memory efficiency related to the frontal cortex, as well as reduced long-term memory related to the hippocampus and other temporal regions of the midbrain. Androgens, especially testosterone, play an important role in memory function whereby the decrease and absence of testosterone leads to cognitive impairment and also neurodegenerative conditions such as Alzheimer's disease, Parkinson's disease, and Huntington's disease. Therefore, in this study, the role of testosterone hormone in social memory, novel object recognition memory, as well as anxiety-like behavior and brain edema induced by a neurotoxic regimen of methamphetamine were investigated.
Materials and methods: This study was conducted on 48 gonadectomized rats in 6 groups including control groups, methamphetamine (6mg/kg), solvent (sesame oil), methamphetamine + testosterone (0.25mg /kg), methamphetamine + testosterone (0.5 mg/kg) and methamphetamine + testosterone (1 mg/kg) were performed. At first, mice were anesthetized and gonadectomy surgery was performed. After 2 weeks of recovery, the evaluation of social memory was done using the three-chamber social interaction test, and anxiety-like behavior index using the open field test. Finally, the animals were killed and the brain tissue was evaluated for brain edema.
Results: The findings of the study showed that social memory was significantly impaired in rats that received methamphetamine compared to the control group (P<0.001). On the other hand, results showed that there was a significant increase in anxiety-like behaviors as well as brain edema in rats that received methamphetamine (P<0.001). Statistical analysis also showed that the administration of testosterone hormone was able to improve cognitive functions and reduce anxiety-like behaviors and brain edema caused by methamphetamine (P<0.05).
Conclusion: Overall, the present study suggests that the male sex hormone testosterone can be effective in improving behavioral disorders and anxiety, as well as brain edema caused by the administration of methamphetamine. Further research is needed to investigate the cellular and molecular mechanisms of the effects of this hormone.