Venous-derived angioblasts generate organ-specific vessels during embryonic development

Formation and remodeling of vascular beds are complex processes orchestrated by multiple signaling pathways. While it is well accepted that vessels of a particular organ display specific features that enable them to fulfill distinct functions, the embryonic origins of tissue-specific vessels, as well as the molecular mechanisms regulating their formation, are poorly understood. The subintestinal plexus of the zebrafish embryo comprises vessels that vascularize the gut, liver and pancreas, and as such represents an ideal model to investigate the early steps of organ-specific vessel formation. Here we show that both arterial and venous components of the subintestinal plexus originate from a pool of specialized angioblasts residing in the floor of the Posterior Cardinal Vein (PCV). Using live imaging of zebrafish embryos, in combination with photoconvertable transgenic reporters, we demonstrate that these angioblasts undergo two phases of migration and differentiation. Initially, a subintestinal vein (SIV) forms and expands ventrally through a bone morphogenetic protein (BMP)-dependent step of collective migration. Concomitantly, a VEGF-dependent shift in the directionality of migration, coupled to the upregulation of arterial markers is observed, which culminates with the generation of the supraintestinal artery (SIA). Altogether our results establish the zebrafish subintestinal plexus as an advantageous model for the study of organ-specific vessel development, and provide new insights into the molecular mechanisms controlling its formation. More broadly, our findings suggest that PCV-specialized angioblasts contribute not only to the formation of the early trunk vasculature, but also to the establishment of late forming-, tissue specific vascular beds

Developmental Coordination during Olfactory Circuit Remodeling in Drosophila

Developmental neuronal remodeling is crucial for proper wiring of the adult nervous system. While remodeling of individual neuronal populations has been studied, how neuronal circuits remodel-and whether remodeling of synaptic partners is coordinated-is unknown. We found that the Drosophila anterior paired lateral (APL) neuron undergoes stereotypic remodeling during metamorphosis in a similar time frame as the mushroom body (MB) gamma-neurons, with whom it forms a functional circuit. By simultaneously manipulating both neuronal populations, we found that cell-autonomous inhibition of gamma-neuron pruning resulted in the inhibition of APL pruning in a process that is mediated, at least in part, by Ca2+-Calmodulin and neuronal activity dependent interaction. Finally, ectopic unpruned MB gamma axons display ectopic connections with the APL, as well as with other neurons, at the adult, suggesting that inhibiting remodeling of one neuronal type can affect the functional wiring of the entire micro-circuit

Pruning deficits of the developing Drosophila mushroom body result in mild impairment in associative odour learning and cause hyperactivity

The principles of how brain circuits establish themselves during development are largely conserved across animal species. Connections made during embryonic development that are appropriate for an early life stage are frequently remodelled later in ontogeny via pruning and subsequent regrowth to generate adult-specific connectivity. The mushroom body of the fruit fly Drosophila melanogaster is a well-established model circuit for examining the cellular mechanisms underlying neurite remodelling. This central brain circuit integrates sensory information with learned and innate valences to adaptively instruct behavioural decisions. Thereby, the mushroom body organizes adaptive behaviour, such as associative learning. However, little is known about the specific aspects of behaviour that require mushroom body remodelling. Here, we used genetic interventions to prevent the intrinsic neurons of the larval mushroom body (γ-type Kenyon cells) from remodelling. We asked to what degree remodelling deficits resulted in impaired behaviour. We found that deficits caused hyperactivity and mild impairment in differential aversive olfactory learning, but not appetitive learning. Maintenance of circadian rhythm and sleep were not affected. We conclude that neurite pruning and regrowth of γ-type Kenyon cells is not required for the establishment of circuits that mediate associative odour learning per se, but it does improve distinct learning tasks

Expertise in Musical Improvisation and Creativity: The Mediation of Idea Evaluation

<div><p>The current study explored the influence of musical expertise, and specifically training in improvisation on creativity, using the framework of the twofold model, according to which creativity involves a process of idea generation and idea evaluation. Based on the hypothesis that a strict evaluation phase may have an inhibiting effect over the generation phase, we predicted that training in improvisation may have a “releasing effect” on the evaluation system, leading to greater creativity. To examine this hypothesis, we compared performance among three groups - musicians trained in improvisation, musicians not trained in improvisation, and non-musicians - on divergent thinking tasks and on their evaluation of creativity. The improvisation group scored higher on fluency and originality compared to the other two groups. Among the musicians, evaluation of creativity mediated how experience in improvisation was related to originality and fluency scores. It is concluded that deliberate practice of improvisation may have a “releasing effect” on creativity.</p></div

Between-group differences in deviance ratings of the most original items (2).

<p>Least-squares means (LS means) are generalizations of covariate-adjusted means used with simulation-based 95% CI; Control variables: age, years of academic education, and participants’ intelligence level; *p<0.05.</p

Diagram depicting the suggested twofold model of creativity.

<p>The model includes two main units: generation and evaluation. A cyclic motion between generation and evaluation through expansion, focus or rejection of ideas is possible. Medium deviant ideas are more likely to become expanded and focused on, while highly deviant ideas are rejected. Training is a latent variable that can influence both the idea generation phase and the idea evaluation phase.</p

The Mediating Effect of Evaluation on the Relationship between Improvisation Experience and Creativity.

<p>Note: *p≤0.05; Bootstrap sample size = 5000; CI  =  Confidence Interval; X - Weekly Hours invested in Improvisation (WHI), M – Deviance, Y – creativity induces.</p

Self-report Measures of Musical Training among Musicians with and without Improvisation Training.

<p>Self-report Measures of Musical Training among Musicians with and without Improvisation Training.</p