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The relationships between feeding activity, brain serotonergic activity level, and energy reserves in eight groups of Arctic char (Salvelinus alpinus) were evaluated using self-feeders in combination with passive integrated transponder (PIT) tags. Serotonin concentrations were measured in the brain stem, telencephalon, and hypothalamus. Energy reserves were measured, as fat levels, in muscle and mesenteric tissue. The self-feeding activity level was found to correlate positively (P < 0.05) with the growth rate and negatively (P < 0.05) with the serotonergic activity levels in the brain stem and telencephalon. No significant relationship was found, however, between the number of trigger activations and the muscle or mesenteric tissue lipid level. One or, in some cases, two fish in each group clearly dominated the activation of the trigger, and showed the highest growth rates and lowest stress levels, measured as brain serotonergic activity. Subordinate fish (one to three individuals) hardly ever activated the trigger, but showed relatively high growth rates and brain serotonergic activity levels that did not differ significantly from those of dominant fish. The remaining individuals showed very little feeding activity and low growth rates. In addition, brain serotonergic activity levels were significantly higher than in fish in the former two categories, indicating that the subordinate fish suffered from stress and had a low social rank.Résumé : La relation entre l'activité alimentaire, l'activité sérotonergique du cerveau et les réserves énergétiques a été évaluée chez huit groupes d'Ombles chevaliers (Salvelinus alpinus) ayant accès à des mangeoires déclenchables à volonté et munis de marqueurs PIT (répondeur intégratif passif). Les concentrations de sérotonine ont été mesurées dans le pédoncule du cerveau, le télencéphale et l'hypothalamus. Les réserves énergétiques (les graisses) ont été mesurées dans le tissu musculaire et le mésentère. La fréquence du déclenchement volontaire des mangeoires était en corrélation positive (P < 0,05) avec le taux de croissance et en corrélation négative (P < 0,05) avec l'activité sérotonergique du pédoncule cérébral et du télencéphale. Aucune relation significative n'a été trouvée entre la fréquence de déclenchement des mangeoires et la concentration de lipides dans les muscles ou le mésentère. Il y avait un poisson dominant (parfois deux) dans chaque groupe : celui-ci s'appropriait le privilège de déclencher les mangeoires, avait le plus haut taux de croissance et était le moins stressé à en juger par son activité sérotonergique cérébrale. Les poissons sous-dominants (un à trois individus) ne déclenchaient à peu près jamais les mangeoires, mais ils avaient des taux de croissance relativement élevés et leur activité sérotonergique cérébrale ne différait pas significativement de celle des poissons dominants. Les autres individus se nourrissaient peu et avaient de faibles taux de croissance; de plus, leur activité sérotonergique cérébrale était significativement plus élevée que c...

Eye movement desensitization and reprocessing (EMDR) has been established as an efficacious therapy for posttraumatic stress disorder (PTSD). The working mechanism of the procedure is, however, still partly unknown. It is therefore important to explore the physiological effects of eye movements and alternative bilateral stimulation. This article describes our research on the effects of eye movements during authentic EMDR sessions of chronic PTSD in refugees with war and torture experiences and places this research in the context of other findings. The findings point to defi nite physiological effects of eye movements; namely a dearousal with increased fi nger temperature and changes in the balance between the parasympathetic and sympathetic autonomous nervous systems.

The populations of gonadotropin-releasing hormone (GnRH)-producing cells within the preoptic area (POA) and terminal nerve (TN) of the brain have been suggested as the neuronal systems mediating social control of sex and gonadogenesis in sequentially hermaphroditic teleosts. In the present study, the number and soma size of GnRH-immunoreactive (GnRH-ir) cells in the POA and TN were studied in male, female and juvenile individuals of the dusky anemonefish (Amphiprion melanopus), a species which displays both male to female sex change and socially controlled sexual maturation. The results showed that the number of POA (but not TN) GnRH-ir cells differ significantly between sexual phases, with males displaying higher cell numbers than both females and juveniles. Soma sizes of POA and TN GnRH-ir cells were larger in females than in males and juveniles. However, this relationship was fully explained by differences in body size. The results indicate that high POA GnRH cell numbers are part of a masculinizing mechanism and support the hypothesis that the POA GnRH cell population plays a central role in initiating or mediating the process of socially induced gonadal and/or behavioural transformations in sequential hermaphrodites.