University of Jyväskylä

About: University of Jyväskylä is a education organization based out in Jyvaskyla, Finland. It is known for research contribution in the topics: Population & Context (language use). The organization has 8066 authors who have published 25168 publications receiving 725033 citations. The organization is also known as: Jyväskylän yliopisto & Kasvatusopillinen korkeakoulu.

Multiple benefits of gregariousness cover detectability costs in aposematic aggregations.

Abstract: Understanding the early evolution of aposematic (warning) coloration has been a challenge for scientists, as a new conspicuous morph in a population of cryptic insects would have a high predation risk and would probably die out before local predators learnt to avoid it1,2,3,4. Fisher5 presented the idea of aggregation benefit through the survival of related individuals; however, his theory has been strongly debated6,7,8 as the mechanisms that favour grouping have never been explored experimentally with the incorporation of detectability costs. Here we create a comprehensive ‘novel world’ experiment with the great tit (Parus major) as a predator to explore simultaneously the predation-related benefits and costs for aposematic aggregated prey, manipulating both group size and signal strength. Our results show that grouping would have been highly beneficial for the first aposematic prey individuals surrounded by naive predators, because (1) detectability risk increased only asymptotically with group size; (2) additional detectability costs due to conspicuous signals were marginal in groups; (3) even naive predators deserted the group after detecting unpalatability (dilution effect); and (4) avoidance learning of signal was faster in groups. None of these mechanisms require kin selection.

A functional MRI study of happy and sad emotions in music with and without lyrics

Abstract: Musical emotions, such as happiness and sadness, have been investigated using instrumental music devoid of linguistic content. However, pop and rock, the most common musical genres, utilize lyrics for conveying emotions. Using participants’ self-selected musical excerpts, we studied their behavior and brain responses to elucidate how lyrics interact with musical emotion processing, as reflected by emotion recognition and activation of limbic areas involved in affective experience. We extracted samples from subjects’ selections of sad and happy pieces and sorted them according to the presence of lyrics. Acoustic feature analysis showed that music with lyrics differed from music without lyrics in spectral centroid, a feature related to perceptual brightness, whereas sad music with lyrics did not diverge from happy music without lyrics, indicating the role of other factors in emotion classification. Behavioral ratings revealed that happy music without lyrics induced stronger positive emotions than happy music with lyrics. We also acquired functional magnetic resonance imaging (fMRI) data while subjects performed affective tasks regarding the music. First, using ecological and acoustically variable stimuli, we broadened previous findings about the brain processing of musical emotions and of songs versus instrumental music. Additionally, contrasts between sad music with versus without lyrics recruited the parahippocampal gyrus, the amygdala, the claustrum, the putamen, the precentral gyrus, the medial and inferior frontal gyri (including Broca’s area), and the auditory cortex, while the reverse contrast produced no activations. Happy music without lyrics activated structures of the limbic system and the right pars opercularis of the inferior frontal gyrus, whereas auditory regions alone responded to happy music with lyrics. These findings point to the role of acoustic cues for the experience of happiness in music and to the importance of lyrics for sad musical emotions.

Effect of isometric strength training on mechanical, electrical and metabolic aspects of muscle function

Abstract: Monozygous twin pairs (two female and four male) were used in a strength training study so that one member of each pair served as training subject (TS) and the other members as nonexercising controls (CS). TS trained four times a week for 12 weeks with maximal isometric knee extensions of the right leg. The parameters studied included muscle strength, endurance time, electromyographic activity, and activities of several key enzymes in nonoxidative and oxidative muscle metabolism. The results disclosed that in addition to a 20% increase in isometric knee extension strength in the trained leg of TS, an average increase of 11% was observed in strength of TS untrained leg. CS did not demonstrate any change in muscle strength. Training also included an improvement in the maintenance of a static load of 60% of the pretraining maximum. Increase in the maximum integrated electromyographic activity (IEMG) of the rectus femoris muscle occurred concomitantly with the knee extension strength. Training also caused reduction in the IEMG/tension ratio at submaximal loads indicating a more economical usage of the rectus femoris muscle. Muscle biopsies taken from the vastus lateralis muscle showed that the enzyme activities of MDH, SDH, and HK were higher, and LDH and CPK lower in the trained leg as compared to the nontrained control leg of TS or to the values of the untrained member of the twin pair. It is concluded that isometric strength training as used in the present study can cause increased recruitment of the available motor unit pool, improved efficiency at submaximal loads, and surprisingly also enchancement of the oxidative metabolism in the muscle.

Effect of protein/essential amino acids and resistance training on skeletal muscle hypertrophy: A case for whey protein

Abstract: Regardless of age or gender, resistance training or provision of adequate amounts of dietary protein (PRO) or essential amino acids (EAA) can increase muscle protein synthesis (MPS) in healthy adults. Combined PRO or EAA ingestion proximal to resistance training, however, can augment the post-exercise MPS response and has been shown to elicit a greater anabolic effect than exercise plus carbohydrate. Unfortunately, chronic/adaptive response data comparing the effects of different protein sources is limited. A growing body of evidence does, however, suggest that dairy PRO, and whey in particular may: 1) stimulate the greatest rise in MPS, 2) result in greater muscle cross-sectional area when combined with chronic resistance training, and 3) at least in younger individuals, enhance exercise recovery. Therefore, this review will focus on whey protein supplementation and its effects on skeletal muscle mass when combined with heavy resistance training.