Functional sex differences in human primary auditory cortex

Background We used PET to study cortical activation during auditory stimulation and found sex differences in the human primary auditory cortex (PAC). Regional cerebral blood flow (rCBF) was measured in 10 male and 10 female volunteers while listening to sounds (music or white noise) and during a baseline (no auditory stimulation). Results and discussion We found a sex difference in activation of the left and right PAC when comparing music to noise. The PAC was more activated by music than by noise in both men and women. But this difference between the two stimuli was significantly higher in men than in women. To investigate whether this difference could be attributed to either music or noise, we compared both stimuli with the baseline and revealed that noise gave a significantly higher activation in the female PAC than in the male PAC. Moreover, the male group showed a deactivation in the right prefrontal cortex when comparing noise to the baseline, which was not present in the female group. Interestingly, the auditory and prefrontal regions are anatomically and functionally linked and the prefrontal cortex is known to be engaged in auditory tasks that involve sustained or selective auditory attention. Thus we hypothesize that differences in attention result in a different deactivation of the right prefrontal cortex, which in turn modulates the activation of the PAC and thus explains the sex differences found in the activation of the PAC. Conclusion Our results suggest that sex is an important factor in auditory brain studies

L'expression du comportement d'incubation chez la dinde et sa maîtrise en élevage

National audienceIncubation behaviour expression in turkey hens and its control in commercial flocks. Broodiness expression still occurs in breeding flocks of different domestic bird species, especially in turkey breeding flocks, although is no longer of practical interest since artificial incubation is now exclusively used in the poultry industry. Moreover, as it is negatively correlated with egg production, it remains a source of economic loss for the poultry industry. The genetic background is a key compound for the rate of expression; however differents exogenous and endogenous factors are well known for their stimulatory properties. Taking into account these factors in addition to genetic selection allows to elaborate different strategies to control incubation behaviour expression. At present, control is based on the use of specific rearing methods and physical treatments which take time. Thus, the practical interest of pharmacological treatments is unquestionable. Recent studies have shown that immunological approachs could be effective to prevent its expression in turkey hens. However, although these approaches are promising, commercial applications are not yet available. For various reasons, selective programs were not effective to fully eradicate broodiness occurence. Preliminary data suggest the presence of specific molecular markers which could be used in order to select against broody behaviour in the future.L’expression du comportement de la couvaison est encore très fréquente chez plusieurs espèces d’oiseaux domestiques dont la dinde, alors qu’elle n’a plus d’intérêt pratique depuis que la totalité des œufs est incubée artificiellement dans l’industrie. En outre, ce comportement est à l’origine de pertes économiques car son expression induit des arrêts de ponte. L’origine génétique des animaux joue un rôle prépondérant quant à leur capacité à exprimer ce comportement, mais différents facteurs exogènes et endogènes sont également connus pour en favoriser l’expression. En tenant compte de ces facteurs, outre la mise en œuvre de programmes de sélection adaptés, diverses stratégies peuvent être envisagées pour que sa maîtrise soit effective en élevage. Elle repose actuellement sur l’usage de techniques d’élevage et de manipulations manuelles complémentaires très contraignantes en terme de main d’œuvre. L’intérêt potentiel de procédés pharmacologiques prophylactiques ou curatifs est donc indéniable. Des travaux récents ont montré que des approches immunologiques pouvaient être efficaces pour prévenir la couvaison chez la dinde. Pour diverses raisons, aucun des procédés testés n’a toutefois encore fait l’objet de développement pour une utilisation à l’échelle industrielle. A ce jour, la sélection génétique par des méthodes classiques n’a pas permis d’éradiquer l’expression de ce comportement. Des résultats préliminaires suggèrent l’existence de marqueurs moléculaires spécifiques chez la poule et la dinde. Si celle-ci se confirme, la mise en œuvre de programmes de sélection appropriés contre le comportement de couvaison sera alors envisageable chez ces espèces

Sequence characterization of K-gene linked region in various chicken breeds

The avian endogenous virus gene (ev21) and dominant sex-linked late feathering (LF) gene (K) are closely associated on the Z chromosome of LF chickens. The K gene is linked to two large repeats: ev21-unoccupied repeat region (URa) and ev21-occupied repeat region (OR). On the other hand, the recessive allele (early feathering, EF: k(+)) is linked to ev21-unoccupied region (URb). These three regions show high similarity but due to minor sequence differences, restriction enzyme treatment distinguishes URa and URb in White Leghorn. However, the applicability of the PCR-RFLP technique or the association between ev21 and K gene are not well investigated in the other breeds or strains. In this study, ev21 loci were detected in White Leghorn, Nagoya, Silky, Geline but not Gifujidori breeds of chickens, and the URa and URb from the various breeds were sequenced. Four types of sequence (URa-1 and URa-2 from LF or ev21 positive, URb-1 and URb-2 from EF or ev21 negative) were identified. At position 1072-1075, URa-2, URb-1 and URb-2 had "GGCC" whereas URa-1 had "AGCC". The transition at 1072 clearly indicates that the PCR-RFLP technique used for White Leghorn is not applicable to Nagoya. Interestingly, both URa-1 and URa-2 were obtained from the ev21 positive sample of Geline. Presence of different sequence of URa in the Geline may explain that fixation of one of sequences to White Leghorn or Nagoya had occurred during breed establishment

Dietary n-3 and n-6 Fatty Acids Alter Avian Pituitary Sensitivity

The effects of dietary saturated and polyunsaturated fatty acids (PUFAs) of the n-3 and n-6 series on avian pituitary sensitivity were investigated by infusing human growth hormone (GH) releasing hormone - fragment 1-29 - and chicken luteinising hormone releasing hormone (LHRH) into catheterized broiler chickens. At 3 weeks of age three groups (n=18; six birds per group) were fed for 6 weeks isonitrogenous and isoenergetic experimental diets containing 80 g/kg of edible tallow (saturated fatty acids), fish oil (n-3 PUFAs) or sunflower oil (n-6 PUFAs). Jugular catheterisation was performed under general anaesthesia during week four of the dietary treatments and the birds allowed 7 days post surgery to recover. A bolus of LHRH (20 b.mug/bird) and a GH releasing hormone (12.5 b.mug/kg) infusion was given on different days to each chicken and serial blood samples taken over a 1 h period. Plasma luteinising hormone and GH concentrations were measured by radioimmunoassay. Pre-infusion GH concentrations were similar for the tallow, fish and sunflower oil dietary groups (5.2±3.9, 5.2±1.0 and 6.1±3.1 ng/ml, respectively), however, GH concentration in response to the GH releasing hormone infusion was elevated in the sunflower oil group (44.7±5.7 ng/ml) when compared to chicken fed tallow (33.7±9.7 ng/ml) or fish oil (21.3±5.0 ng/ml). There was a significant decrease (