Visual Laterality of Calf–Mother Interactions in Wild Whales

Behavioral laterality is known for a variety of vertebrate and invertebrate animals. Laterality in social interactions has been described for a wide range of species including humans. Although evidence and theoretical predictions indicate that in social species the degree of population level laterality is greater than in solitary ones, the origin of these unilateral biases is not fully understood. It is especially poorly studied in the wild animals. Little is known about the role, which laterality in social interactions plays in natural populations. A number of brain characteristics make cetaceans most suitable for investigation of lateralization in social contacts.) in the greatest breeding aggregation in the White Sea. Here we show that young calves (in 29 individually identified and in over a hundred of individually not recognized mother-calf pairs) swim and rest significantly longer on a mother's right side. Further observations along with the data from other cetaceans indicate that found laterality is a result of the calves' preference to observe their mothers with the left eye, i.e., to analyze the information on a socially significant object in the right brain hemisphere.Data from our and previous work on cetacean laterality suggest that basic brain lateralizations are expressed in the same way in cetaceans and other vertebrates. While the information on social partners and novel objects is analyzed in the right brain hemisphere, the control of feeding behavior is performed by the left brain hemisphere. Continuous unilateral visual contacts of calves to mothers with the left eye may influence social development of the young by activation of the contralateral (right) brain hemisphere, indicating a possible mechanism on how behavioral lateralization may influence species life and welfare. This hypothesis is supported by evidence from other vertebrates

Prenatal testosterone does not explain sex differences in spatial ability

The most consistent sex differences in cognition are found for spatial ability, in which males, on average, outperform females. Utilizing a twin design, two studies have shown that females with male co-twins perform better than females with female co-twins on a mental rotation task. According to the Twin Testosterone Transfer hypothesis (TTT) this advantage is due to in-uterine transmission of testosterone from males to females. The present study tested the TTT across 14 different spatial ability measures, including mental rotation tasks, in a large sample of 19–21-year-old twins. Males performed significantly better than females on all spatial tasks, with effect sizes ranging from η2 = 0.02 to η2 = 0.16. Females with a male co-twin outperformed females with a female co-twin in two of the tasks. The effect sizes for both differences were negligible (η2 < 0.02). Contrary to the previous studies, our results gave no indication that prenatally transferred testosterone, from a male to a female twin, influences sex differences in spatial ability

Chronic administration of androgens with actions at estrogen receptor beta have anti-anxiety and cognitive-enhancing effects in male rats

Androgen levels decline with aging. Some androgens may exert anti-anxiety and cognitive-enhancing effects; however, determining which androgens have anxiolytic-like and/or mnemonic effects is of interest given the different mechanisms that may underlie some of their effects. For example, the 5α-reduced metabolite of testosterone (T), dihydrotesterone, can be further converted to 5α-androstane,17β-diol-3α-diol (3α-diol) and 5α-androstane,17β-diol-3β-diol (3β-diol), both of which bind with high affinity to the beta isomer of the intracellular estrogen receptor beta (ERβ). However, androsterone, another metabolite of T, does not bind well to ERβ. To investigate the effects of T metabolites, male rats were subjected to gonadectomy then implanted with silastic capsules of 3α-diol, 3β-diol, androsterone, or oil control. After recovery, the rats were tested in elevated plus maze (EPM), light/dark transition (LD), and Morris water maze (MWM). 3α-diol both decreased anxiety-like behavior in the EPM and LD, and increased cognition in MWM, while 3β-diol improved cognition in MWM, but had no effects on anxiety behavior, compared to vehicle or androsterone. These data suggest that the actions of 3α-diol and 3β-diol at ERβ may be responsible for some of testosterone’s anti-anxiety and cognitive-enhancing effects

To beg or to freeze: multimodal sensory integration directs behavior in a tadpole

Effective coordination of behaviors such as foraging and avoiding predators requires an assessment of cues provided by other organisms. Integrating cues from multiple sensory modalities may enhance the assessment. We studied cue integration by tadpoles of Oophaga pumilio, which live in small arboreal water pools. In this species, mothers periodically visit their tadpoles and feed them with unfertilized eggs. When mothers visit, tadpoles beg conspicuously by vibrating until fed. However, animals other than mother frogs including potential predators may visit water pools. Thus, when a visitor appears, tadpoles must use visitor cues to decide whether to beg or to remain inactive to avoid predation. To elucidate the cues that prompt these behaviors, we videotaped behavior of O. pumilio tadpoles in response to isolated and multimodal cues. Tadpoles swam more when exposed to visual or visual and chemical cues of adult O. pumilio but only exhibited begging when exposed to visual, chemical, and tactile cues together. Visual, chemical, and tactile cues from either male or female adult O. pumilio stimulated swim- ming and begging, but the same cues from similarly sized heterospecific frogs did not. Lastly, tadpoles exposed to a potential predator did not beg and swam less than tadpoles with no stimulus. Together, these findings suggest that O. pumilio tadpoles use multimodal cues to modulate swimming behavior accordingly in the presence of egg provisioners, predators, and other visitors and that tadpole begging is induced by multimodal cues of conspecific frogs such that tactile and perhaps chemical cues supplement visual cues.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto Clodomiro Picado (ICP