Genetic Functional Dissection of the Synaptic Output of a Dual-Function Integrating Neuron

Animals must vary their behavior in response to changes in their environment, but behavior also remains consistent over time. This thesis focuses on a single interneuron, RIM, and a single behavior, the reversal, to better understand how the circuits driving motor outputs accomplish the seemingly contradictory tasks of generating appropriate and variable behaviors. In the compact and well-defined nervous system of C. elegans, the interneuron RIM is an important part of the reversal behavior circuit that contributes to sensory integration, behavioral variability, generation of behavioral states, and learning. RIM releases both glutamate and the biogenic amine tyramine (~noradrenaline) and forms gap junctions with neurons that govern various aspects of C. elegans locomotion. RIM is the major source of tyramine in C. elegans, and this output is known to extend reversal length of spontaneous and evoked reversals and to sharpen turns during escape response. However, the roles of RIM glutamate and RIM gap junctions in organizing reversal behavior have remained nebulous. I combine cell-specific genetic manipulations, behavioral analyses, and both manipulations and observations of neural activity to dissect the diverse synaptic outputs of the interneuron RIM. I reveal a role for RIM glutamate in spontaneous reversal behavior and show that RIM glutamate and RIM tyramine differentially regulate spontaneous reversals. Through comparative analysis of the exo- and endocytosis dynamics of RIM glutamate and tyramine, I provide evidence that they released from RIM under the same conditions and with similar dynamics, and that tyramine may also be released from a distinct, slower vesicle class. I also find that both RIM chemical synapses and electrical synapses are bidirectional regulators of C. elegans locomotion, stabilizing both the forward state and reversal state. I conclude that RIM is a dual-function neuron, able to both promote and inhibit reversal behavior

«Indissolubile vinculum karitatis». Pier Damiani e Alfano I di Salerno

The epistle 49 by Peter Damian contains an original allegorical interpretation of the Jewish Sabbath as a day of rest, enriched by a mystical exegesis of the biblical Hexameron, in which the six days of creation correspond to the inner journey of man called to intimately unite with God. Peter Damian expresses this process of deification through the two images of man as microcosm and sovereign of creation and man as temple of God. The main source of Damian’s text seems to be the De natura hominis by Nemesius of Emesa, which he knows thanks to the translation of Alfanus I of Salerno, one of the recipients of the epistle: this is confirmed by textual evidences, but also by a preliminary historical and historiographic reconstruction of the clue of friendship that binds Peter Damian to the archbishop of Salerno

«Indissolubile vinculum karitatis». Pier Damiani e Alfano I di Salerno

The epistle 49 by Peter Damian contains an original allegorical interpretation of the Jewish Sabbath as a day of rest, enriched by a mystical exegesis of the biblical Hexameron, in which the six days of creation correspond to the inner journey of man called to intimately unite with God. Peter Damian expresses this process of deification through the two images of man as microcosm and sovereign of creation and man as temple of God. The main source of Damian’s text seems to be the De natura hominis by Nemesius of Emesa, which he knows thanks to the translation of Alfanus I of Salerno, one of the recipients of the epistle: this is confirmed by textual evidences, but also by a preliminary historical and historiographic reconstruction of the clue of friendship that binds Peter Damian to the archbishop of Salerno

Hugo de Sancto Victore, De oratione dominica. De septem donis Spiritus sancti

Lorsqu’en 2015, Francesco Siri a édité le recueil Le Pater noster au xiie siècle (Le Pater noster au xiie siècle. Lectures et usages, Turnhout, Brepols, [Bibliothèque d’histoire culturelle du Moyen Âge, 15], 2015), en écrivant sur Hugues de Saint-Victor, commentateur du Pater Noster, il a probablement réalisé à ce moment-là la nécessité d’une nouvelle édition critique sur le De oratione dominica et sur le De septem donis Spiritus sancti. En effet, bien qu’il se soit consacré à ce sujet depuis..