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Hormonal and Nonhormonal Mechanisms of Sexual Differentiation of the Zebra Finch Brain: Embracing the Null Hypothesis
Published in Akira Matsumoto, Sexual Differentiation of the Brain, 2017
The effects of estrogen led to the hypothesis that male song system development is the result of endogenous estrogen action early in development. By analogy to mammalian sexual differentiation, the idea was that during early development males might secrete more estrogen than females. Alternatively, males might secrete more testosterone, which in turn would lead via aromatization to a higher level of estrogen in brain. Support for this hypothesis comes from direct and indirect experimental tests. The one direct test is the experiment described in the preceding paragraph, which shows that estrogen masculinizes females. Indirect support has come from three experimental findings. First, Hutchison et al.45 found that hatchling males have higher plasma levels of estrogen than females. However, this result is in some doubt because two other studies failed to replicate it.46,47 Second, estrogen receptors are found in and near HVC (high vocal center), one of the brain regions importantly involved in song.48–51 Third, aromatase is expressed in high abundance in or near several regions within the telencephalic song circuit during developmental periods when estrogen can masculinize females.51 These experiments establish the ability of estrogen to masculinize, and establish the sites of estrogen synthesis and action near HVC and other parts of the song circuit during an estrogen-sensitive developmental period.
ENTRIES A–Z
Published in Philip Winn, Dictionary of Biological Psychology, 2003
A large structure in the FOREBRAIN of birds, divisible into a number of subnuclei (such as intermediate and medial hyperstriatum ventrale). It is important in IMPRINTING and it is sensitive to the structure of conspecific BIRDSONG. Indeed, the hyperstriatum ventrale pars caudale appears to be critical for the acquisition, perception and production of birdsong and is often now referred to as the HIGHER VOCAL CENTRE (HVC).
Continuity of illicit drug use among Malay patients attending methadone clinics in Kelantan, Malaysia
Published in Journal of Ethnicity in Substance Abuse, 2023
Syazilawaty Ab Lloh, Noraini Mohamad, Salziyan Badrin, Ruzilawati Abu Bakar, Imran Ahmad
Prevalence of Hepatitis C virus (HCV) infection among methadone-maintained participants has been described in numerous studies (Ali et al., 2018; Baharom et al., 2012; Lee et al., 2012; Tran et al., 2012), but its association with the continuity of drug use is not widely reported in the previous studies. In our study, those who had hepatitis C infection had lower illicit drug use continuity as per self-report and urine testing for drugs. Our finding was not parallel with results from another previous study (Lee et al., 2012). Many studies have reported the presence of extrahepatic symptoms of HVC infection, such as fatigue, muscle ache, difficulty sleeping, and depression, subsequently affecting the quality of life of the affected patients (Basseri et al., 2010; Miller et al., 2012; Yamini et al., 2011). The presence of extrahepatic symptoms was thought to lead to increased use of illicit drugs or self-medication to relieve the symptoms.
Communicating value to patients-a high-value care communication skills curriculum
Published in Postgraduate Medicine, 2021
Alisa Duran, Crystal Donelan, Jill Bowman Peterson, Sophia P. Gladding, Peter Weissmann, Craig S. Roth
Our study is limited in that it included a small sample size at a single institution. Additionally, we performed a single assessment of HVC communication skills at the end of the intervention period. Our outcomes may have differed with assessment of skills in multiple SP encounters to assess for baseline and growth as well as the use of a validated behavioral instrument more specific to our needs instead of the CARE empathy scale. Challenges faced during our intervention period included scheduling conflicts between the small groups, the SP encounters, and our new block schedule, leading to difficulties with curriculum delivery. As a result, some interns in the high-intensity group reported dissatisfaction with the process and this may have impacted their overall impression of the curriculum. One resident reported the scheduling conflicts led them to rate the overall curriculum more poorly. Our ability to detect changes in residents’ skill between the high intensity and standard participants may be limited by the relatively robust curriculum offered to all residents in the CASE experience. Conceivably, our project may demonstrate a ‘ceiling effect’ beyond which our evaluation instrument could not detect an incremental skill differential between groups. Finally, residents’ experiences during the PGY-1 year are profound and complex. Accounting for the countless variables that could influence any individual’s behavior and skill far exceeded the scope of this project.
Dissociation of circadian activity and singing behavior from gene expression rhythms in the hypothalamus, song control nuclei and cerebellum in diurnal zebra finches
Published in Chronobiology International, 2019
Abhilash Prabhat, Neelu Anand Jha, S. K. Tahajjul Taufique, Vinod Kumar
We collected brains at 6 h intervals (n = 5/time point/condition), beginning at ZT2 for LD and LL-AR birds (since there was absence of the reference point for these birds) or CT2 (2 h after the onset of activity) for LL-R birds, as per methods described in previous publications from our laboratory (Majumdar et al. 2015; Mishra et al. 2017, 2018; Singh et al. 2015). Briefly, birds were decapitated, which is a quick unanticipated procedure, lasts for only a few seconds and preserves the transcript integrity (Pekny et al. 2014; Staib-Lasarzik et al. 2014). The head was put on ice and brain was quickly removed, frozen on dry ice and stored at −80°C until processed further. We excised out specific brain areas, namely the song control nuclei (Area X and HVC), hypothalamus and cerebellum. Whereas we separated the cerebellum by fine forceps to isolate the other areas remaining brain was manually sliced in the coronal plane in 1 mm thick sections onto the freezing (−20°C) Leica cryostat platform, as described by Fusani et al. (2001) and Thompson et al. (2012). Visually marked Area X and HVC under the stereomicroscope (Steriomikroskop Stemi DV4, Zeiss, Gottingen, Germany) were excised out from both cerebral hemispheres (Fusani et al. 2001; Thompson et al. 2012). Similarly, we excised out hypothalamus roughly in shape of an inverted V (ʌ), as visually marked under the stereomicroscope by longitudinal incisions placed at 45° angle on either side of the third ventricle (Kuenzel and van Tienhoven 1982; Mishra et al. 2018; Olkowicz et al. 2016). Figure 1 shows landmarks for each brain area isolated for this study, based on zebra finch brain atlas (Nixdorf-Bergweiler and Bischof 2007). The brain was never thawed to maintain the tissue quality and transcript integrity (Botling et al. 2009; Mishra et al. 2018), and the isolated tissue samples were stored at −80°C until processed for gene expression assays.