Biogeographical analysis of rodent endemism and distributional congruence in the southern–central Andes (north‐western Argentina)

The recognition of areas of endemism (AEs) is important for conservation biology and biogeographical regionalization. Our objective was to quantitatively identify AEs and distributional congruence patterns of native rodents at the tropical/temperate transition in the central Andes. We analysed 6200 geo‐referenced distributional records of 80 species in north‐western Argentina using NDM/VNDM software. We found 20 AEs defined by 22 endemic species (27% of the total rodent fauna) and 34 patterns of distributional congruence in non‐endemic rodents. Geographical range congruence follows two main patterns running parallel along the Andes. One is related to the humid eastern slopes of the Andes (Argentinean Yungas forest) and the other to the high Andes (Argentinean Puna plateau). Endemism was mainly restricted to the southernmost part of the Yungas forest and adjacent dryer valleys (Monte desert). Species diversity was highest in the northern sector of the Argentinean Yungas forest, where several species reach their southern distributional range. This incongruence among hotspots of diversity and endemism has also been also noted in diversity studies at continental and global scales. Our results provide a starting point for conservation planning in the southernmost Central Andes, which combines the taper of tropical diversity and range‐restricted species endemic to the tropical–temperate transition. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 112 , 163–179.     

The effects of dopamine on temperature regulation in goldfish

Summary Microinjections of dopamine (DA) were made into specific forebrain loci in goldfish (Carassius auratus: 40–85 g) to study the involvement of DA in behavioral thermoregulation. Injections of 25, 50, 100 and 250 ng DA into the anterior aspect of the nucleus preopticus periventricularis (NPP) led to consistent, dose-dependent decreases in selected temperature was observed following injections of 5 or 10 ng DA. Injections of the control solution were without effect.Injections of DA into other forebrain loci, including the posterior half of the NPP, either had no thermoregulatory effect or had minor thermoregulatory effects which, in comparison to injections into the most effective sites, were inconsistent and required larger doses to obtain. The decrease in selected temperature following injections of 100 ng DA into the anterior NPP was blocked by haloperidol, a dopaminergic antagonist, but not by phentolamine, a noradrenergic antagonist. Injections of haloperidol alone resulted in a minor, but statistically significant, increase in selected temperature.The most sensitive DA sites lie caudal to the sites most sensitive to norepinephrine within the anterior NPP. DA acts on the dopaminergic receptors of central thermoregulatory neurons in the anterior NPP of goldfish. These receptors appear to mediate behavioral responses to excessively warm environments.Abbreviations DA dopamine - NE norepinephrine - NPP nucleus preopticus periventricularis - PBS phosphate buffer solution     

Genetic polymorphisms of the endocannabinoid system

Disturbances in the endocannabinoid system has been linked to diseases and conditions such as Parkinson's, schizophrenia, pain, energy metabolism, immune modulation, and bone density. Since the early 1990s, a number of genetic polymorphisms in the genes and proteins of the endocannabinoid system have been characterized. Currently identified genetic polymorphisms of the endocannabinoid system are reviewed here with particular consideration given to polymorphisms linked to drug and alcohol abuse, schizophrenia, other mental disorders, and energy metabolism.     

Growth-mortality tradeoffs and 'personality traits' in animals

Consistent individual differences in boldness, reactivity, aggressiveness, and other 'personality traits' in animals are stable within individuals but vary across individuals, for reasons which are currently obscure. Here, I suggest that consistent individual differences in growth rates encourage consistent individual differences in behavior patterns that contribute to growth-mortality tradeoffs. This hypothesis predicts that behavior patterns that increase both growth and mortality rates (e.g. foraging under predation risk, aggressive defense of feeding territories) will be positively correlated with one another across individuals, that selection for high growth rates will increase mean levels of potentially risky behavior across populations, and that within populations, faster-growing individuals will take more risks in foraging contexts than slower-growing individuals. Tentative empirical support for these predictions suggests that a growth-mortality perspective may help explain some of the consistent individual differences in behavioral traits that have been reported in fish, amphibians, reptiles, and other animals with indeterminate growth.     

The initial stage of reversal learning is impaired in mice hemizygous for the vesicular glutamate transporter (VGluT1)

Behavioral flexibility is a complex cognitive function that is necessary for survival in changeable environments. Patients with schizophrenia or Parkinson's disease often suffer from cognitive rigidity, reducing their capacity to function in society. Patients and rodent models with focal lesions in the prefrontal cortex (PFC) show similar rigidity, owing to the loss of PFC regulation of subcortical reward circuits involved in behavioral flexibility. The vesicular glutamate transporter (VGluT1) is preferentially expressed at modulatory synapses, including PFC neurons that project to components of the reward circuit (such as the nucleus accumbens, NAc). VGluT1^+/? mice display behavioral phenotypes matching many symptoms of schizophrenia, and VGluT1 expression is reduced in the PFC of patients with schizophrenia and Parkinson's disease. Thus, it appears likely that VGluT1‐expressing synapses from PFC play a key role in behavioral flexibility. To examine this hypothesis, we studied behavioral flexibility in VGluT1^+/? mice by testing reversal learning in a visual discrimination task. Here, we show that VGluT1^+/? mice acquired the initial visual discrimination at the same rate as controls. However, they failed to suppress responses to the previously rewarded stimulus following reversal of reward contingencies. Thus, our genetic disruption of modulatory glutamatergic signaling, including that arising from PFC, appears to have impaired the first stage of reversal learning (extinguishing responses to previously rewarded stimuli). Our data show that this deficit stems from a preservative phenotype. These findings suggest that glutamatergic regulation from the cortex is important for behavioral flexibility and the disruption of this pathway may be relevant in diseases such as schizophrenia.     

Executive dysfunction and the relation with behavioral problems in children with 47,XXY and 47,XXX

Neuroimaging studies have shown that having an extra X chromosome is associated with abnormal structure and function of brain areas in the frontal lobe, which is crucially involved in executive functioning. However, there is little of knowledge of the type and severity of executive dysfunction, and the impact on emotional and behavioral problems. The present study aims to provide in this. In total, 40 children (23 boys with 47,XXY and 17 girls with 47,XXX) with an extra X chromosome and 100 non‐clinical controls (47 boys and 53 girls) participated in the study. The participants were 9–18 years old. Processing speed and executive functioning were assessed using the Amsterdam Neuropsychological Testbattery (ANT) and the Dysexecutive Questionnaire (DEX). Problems in emotional and behavioral functioning were assessed with the Childhood Behavior Checklist (CBCL). Children with an extra X chromosome showed deficits in inhibition, mental flexibility, sustained attention and visual working memory. Parental report showed high levels of everyday manifestations of executive dysfunction. More severe inhibition difficulties were associated with higher levels of thought problems, aggression and rule breaking behavior. Boys and girls with an extra X chromosome could not be differentiated based on severity of executive dysfunction, however, girls had lower information processing speed than boys. These findings suggest that executive dysfunction may be part of the phenotype of children with an extra X chromosome, impacting the ability to function adequately in everyday life. Furthermore, children with impairments in inhibition may have more problems in regulating their thinking, emotions and behavior.     

Modification of leech behavior following foraging for artificial blood

In this study we examined whether the foraging for artificial blood affected the behavioral responsiveness of leeches to electrical stimulation of the body wall. After foraging for artificial blood, electrical stimulation of the posterior end of the leech significantly increased the percentage of stimulation trials that elicited locomotory activity—swimming and crawling—compared to the behaviors elicited when leeches did not forage or foraged for normal saline. On the other hand, shortening always dominated the behavioral profile of the leech to anterior stimulation even after foraging for artificial blood. In intact anterior end-isolated nerve cord preparations, we also found that application of artificial blood to the intact anterior end was sufficient to modify motor responsiveness to DP nerve stimulation. Full strength artificial blood had an overall negative effect on the likelihood of DP nerve stimulation initiating swimming and on the average length of elicited swim episodes compared to when pond water surrounded the anterior end. Application of a 10% solution of artificial blood to the anterior end led to an increase in the likelihood of DP nerve stimulation eliciting swimming.     

Early experience shapes the development of behavioral repertoires of hatchling snakes

Snakes are obligate predatory organisms that consume prey whole, and despite their precocious nature, snakes must develop effective feeding skills, especially when encountering large prey. I conducted two experiments that document the development of behavioral repertoires for naïve hatchling trinket snakes, Coleognathus helena. In the first experiment, I examined how experience with prey of different relative prey mass encountered at regular feeding intervals affects hatchling feeding response. I also examined whether hatchling feeding performance improved over time. Improvement was evaluated on the frequency of the most effective behavioral states such as complex prey restraint behaviors and anterior-first ingestion. In the second experiment I tested whether feeding experience with prey of a particular size influences the way hatchlings respond to a novel prey size. All hatchlings improved their predatory behavior when prey size and number of trials were controlled. Hatchlings feeding on larger prey, however, showed greater overall improvement in their feeding behavior and were quick to integrate complex prey restraint behaviors such as constriction into their feeding repertoire. Despite the fact that early experience with one prey size seemed to shape their restraint repertoire during their first four feeding events, hatchlings remained flexible and responded to prey of a novel size with size-specific prey restraint behaviors.     

Traveling in clutter: Navigation in the Central Australian desert ant Melophorus bagoti

The Central Australian desert ant Melophorus bagoti is the most thermophilic ant on the continent. It comes out to forage during the hottest part of the day in the summer months. The ant shares a cluttered, plant-filled habitat with other arthropods and uses a range of navigational strategies. We review recent studies on this species concerning its use of habitual routes, distant landmarks, landmarks around the nest, and path integration, which is keeping track of the distance and direction traveled from one's starting point. Functional predictions concerning the acquisition, retention, and integration of memories of distances and of landmarks are also reviewed, illuminating the behavioral ecology of spatial cognition.     

Analyzing variable behavioral contingencies: Are certain complex skills homologous with locomotion?

This paper considers behavioral contingencies that change as a function of time, of the individual's own behavior (as in locomotion and reading), of the behavior of other parties or of interactions with them. A detailed analysis of locomotion and of reading out loud shows that the behavioral contingencies for these are virtually the same. The terrain being traversed and the locomotion behavior involved are shown to be analogous to a segment of text being read and the articulation of the words. In both cases, successive upcoming segments are perceived and processed, and during the processing phases, motor behavior is formulated. In both, the smooth concatenation of the motor phases for successive segments requires buffering. Both involve corrective or digressive actions in response to obstacles or unanticipated stimuli encountered. Both involve looking ahead at the upcoming segment and processing it while the motor phase of the prior segment is still in progress. For both, the size, entropy, familiarity, and other attributes of the upcoming segment are parameters of the performance. It is suggested that locomotion has similar parallels with certain other complex skills, such as listening, copying, receiving Morse code, simultaneous interpreting, and certain types of performance, and may therefore be their phylogenetic prototype and biological homologue.