Music Playing and Interhemispheric Communication: Older Professional Musicians Outperform Age-Matched Non-Musicians in Fingertip Cross-Localization Test.

OBJECTIVE: Numerous investigations have documented that age-related changes in the integrity of the corpus callosum are associated with age-related decline in the interhemispheric transfer of information. Conversely, there is accumulating evidence for more efficient white matter organization of the corpus callosum in individuals with extensive musical training. However, the relationship between making music and accuracy in interhemispheric transfer remains poorly explored. METHODS: To test the hypothesis that musicians show enhanced functional connectivity between the two hemispheres, 65 professional musicians (aged 56-90 years) and 65 age- and sex-matched non-musicians performed the fingertip cross-localization test. In this task, subjects must respond to a tactile stimulus presented to one hand using the ipsilateral (intra-hemispheric test) or contralateral (inter-hemispheric test) hand. Because the transfer of information from one hemisphere to another may imply a loss of accuracy, the value of the difference between the intrahemispheric and interhemispheric tests can be utilized as a reliable measure of the effectiveness of hemispheric interactions. RESULTS: Older professional musicians show significantly greater accuracy in tactile interhemispheric transfer than non-musicians who suffer from age-related decline. CONCLUSIONS: Musicians have more efficient interhemispheric communication than age-matched non-musicians. This finding is in keeping with studies showing that individuals with extensive musical training have a larger corpus callosum. The results are discussed in relation to relevant data suggesting that music positively influences aging brain plasticity.

Age-related decline in interhemispheric transfer of tactile information: The fingertip cross-localization task.

According to the disconnection hypothesis of cognitive aging, cognitive deficits associated with brain aging could be a result of damage to connective fibres. It has been suggested that the age-related decline in cognitive abilities is accompanied by age-related changes in interhemispheric communication ensured by commissural fibres. This study aimed to contribute to this topic by investigating the effects of aging on the efficiency of interhemispheric transfer of tactile information. A total of 168 right-handed subjects, aged 20-90 years, have been tested using the fingertip cross-localization task: the subject must respond to a tactile stimulus presented to one hand using the ipsilateral (uncrossed condition) or contralateral hand (crossed condition). Because the crossed task requires interhemispheric transfer of information, the value of the difference between the uncrossed and crossed conditions (CUD) can be deemed to be a reliable measure of the efficiency of the interhemispheric interactions. The uncrossed condition was more accurate than the crossed condition for all ages. However, the degree of the CUD was significantly age-dependent. The effectiveness of the interhemispheric transfer of tactile information decreased significantly with age and may indicate the occurrence of age-related changes of the corpus callosum. Considerably, performance appears to decline around the seventh decade of life with the fastest decline in the subsequent decades. The results suggest a relationship between brain aging and the efficiency of the interhemispheric transfer of tactile information. The findings are discussed in relation to the strategic role of white matter integrity in preserving behavioural performances.

Effects of acoustic stimulation on biochemical parameters in the digestive gland of Mediterranean mussel Mytilus galloprovincialis (Lamarck, 1819).

Underwater sounds generated by anthropogenic activity can cause behavior changes, temporary loss of hearing, damage to parts of the body, or death in a number of marine organisms and can also affect healing and survival. In this study, the authors examined the effects of high-frequency acoustic stimulations on a number of biochemical parameters in the Mediterranean mussel, Mytilus galloprovincialis. During the experiment, animals were placed in a test tank and exposed to acoustic signals [a linear sweep ranging from 100 to 200 kHz and lasting 1 s, with a sound pressure level range of between 145 and 160 dBrms (re 1µParms)] for 3 h. Total haemocyte count was assessed and glucose levels, cytotoxic activity and enzyme activity (alkaline phosphatase, esterase and peroxidase) in the digestive gland were measured. For the first time, this study suggests that high-frequency noise pollution has a negative impact on biochemical parameters in the digestive gland.

Underwater high frequency noise: Biological responses in sea urchin Arbacia lixula (Linnaeus, 1758).

Marine life is extremely sensitive to the effects of environmental noise due to its reliance on underwater sounds for basic life functions, such as searching for food and mating. However, the effects on invertebrate species are not yet fully understood. The aim of this study was to determine the biochemical responses of Arbacia lixula exposed to high-frequency noise. Protein concentration, enzyme activity (esterase, phosphatase and peroxidase) and cytotoxicity in coelomic fluid were compared in individuals exposed for three hours to consecutive linear sweeps of 100 to 200 kHz lasting 1 s, and control specimens. Sound pressure levels ranged between 145 and 160 dB re 1µPa. Coelomic fluid was extracted and the gene and protein expression of HSP70 with RT-PCR was evaluated on coelomocytes. A significant change was found in enzyme activity and in the expression of the HSP70 gene and protein compared to the control. These results suggested that high-frequency stimuli elicit a noise-induced physiological stress response in A. lixula, confirming the vulnerability of this species to acoustic exposure. Furthermore, these findings provide the first evidence that cell-free coelomic fluid can be used as a signal to evaluate noise exposure in marine invertebrates.

Basic knowledge of social hierarchies and physiological profile of reared sea bass Dicentrarchus labrax (L.).

The effects of social hierarchies (dominant/subordinate individuals), such as aggressiveness, feeding order, and territoriality, are some of the characteristics used for describing fish behaviour. Social hierarchy patterns are still poorly understood in European-reared sea bass (Dicentrarchus labrax). In this work, we examine the social interactions among captive fish integrating behavioural and physiological profiles. Groups of three fish with EMG (electromyogram) radio transmitters were monitored for two weeks via video recording. Plasma levels of cortisol, glucose, lactate and lysozyme as well as haematological parameters such as haemoglobin, haematocrit and RBCC (red blood cell count) were measured at the beginning and end of the experiments. Behaviour and muscle activity were monitored daily. The results highlighted that the social hierarchic order was established after one to two days, and it was maintained throughout the experimental period. Dominant and subordinate fish (ß and γ) showed significant differences in muscle activity, hormonal profile (cortisol), aspecific immunity (lysozyme), carbohydrate metabolism (lactate) and behavioural patterns (food order and aggressiveness). This holistic approach helps to provide insights into the physiological status of the subordinate (ß and γ) and dominant individuals. These data have wide implications for aquaculture practice.

Evaluation of waterborne exposure to heavy metals in innate immune defences present on skin mucus of gilthead seabream (Sparus aurata).

Aquatic animals are continuously exposed to chemical pollutants but the effects evoked in skin surfaces, which receive the most direct contact with them, are poorly investigated. Terminal carbohydrate composition and immunological components present in skin mucus of gilthead seabream (Sparus aurata L.) specimens exposed to waterborne sublethal dosages of heavy metals [arsenic (As2O3), cadmium (CdCl2) and mercury (CH3HgCl) at 5, 5 and 0.04 µM, respectively for 2, 10 and 30 days were analysed. Moreover, the presence of a fucose binding lectin (FBL) was evaluated by western blot and the protein profiles were by SDS-PAGE and HPLC. Results showed little effects of heavy metals in the presence of several terminal carbohydrates with few increments or decrements. Most of the enzyme activities related to immune responses were increased upon heavy metal exposure in the skin mucus including bactericidal activity. Methylmercury produced the most dramatic changes increasing all the activities. Moreover, the FBL was undetected in any of the control fish skin mucus but was evident in all the heavy metal exposed fish. In addition, As and Cd produced a clear change in the protein profile as evidenced by the lack of a protein band of around 12 kDa which is absent. These protein changes were more evident with the HPLC study showing the presence of different peaks and differences in intensity. The present results could be useful for better understanding the role and their behaviour of the mucosal immunity in skin as a key component of the innate immune system against pollutants.