Zebrafish anxiety-like behavior was assessed in the novel tank test after the formation of dominant-subordinate hierarchies. Ten pairs of animals were subjected to dyadic interactions for 5 days, and compared with control animals. After this period, a clear dominance hierarchy was established across all dyads, irrespective of sex. Social status affected parameters of anxiety-like behavior in the novel tank test, with subordinate males and females displaying more bottom-dwelling, absolute turn angle, and freezing than dominant animals and controls. The results suggest that subordinate male and female zebrafish show higher anxiety-like behavior, which together with previous literature suggests that subordination stress is conserved across vertebrates.

No abstract

Background In Brazil, the elderly population has the highest growth rate. The estimated number of aged is 32 million for the year 2020. The city of Maraba, in the state of Para, located in and Brazil's Amazon region presents a very low Urban Development Index for Longevity. Previous studies have shown that music can enhance the willingness of the elderly to participate in other social activities, contributing to social interaction and, consequently, to prevention of depression. In addition to an important resource to stimulate memory and attention. Method The study was developed with 13 elderly from two public long term care institutions who completed all the stages of this study. They were evaluated through a neuropsychological assessment tool. It was composed of 9 objective tests about memory, executive function, attention, praxis and information processing speed. The instruments was applied in two moments: before and after the musical stimulation intervention which consisted of 12 weekly sessions lasting one and a half hours. Result 92.3% were man, 69.2% aged 60‐70 years and 73% with a low level of formal education (Table 1). All had the diagnosis of mild to moderate dementia. There was significant improvement in cognitive performance of sustained attention and immediate recall short‐term memory between the baseline application and the post‐intervention (‐3.8 ± 2.0 vs. ‐2.2 ± 1.8, p = 0.07 and 3.6 ± 1.1 vs. 4.8 ± 2.0, p = 0.02, Table 2 and Figures 1 and 2). Significant improvement in mood symptoms was also observed (5.5 ± 2.0 vs. 4.5 ± 1.8, p = 0.04, Table 2 and Figure 3). Conclusion The results corroborate with other studies, demonstrating the effectiveness of musical stimulation as a way to slow the progression of cognitive impairment, also contributing to euthymic mood. Thus, this would be an accessible and low cost technique for performing cognitive stimulation/rehabilitation in elderly with dementia and possibly delaying the onset or progression of mood and/or cognitive symptoms. Even to elderly people living in long‐term care institutions who show a faster progression of cognitive decline compared to community‐dwelling elderly also benefit from this intervention strategy.