During the first part of my talk I will briefly introduce my research interests over the past years, especially on the use of seabirds as sentinel of climate change in the Southern Ocean, and on the changes over lifetime in the foraging strategies of seabirds. During the second part, I will focus on recent findings on the flight of frigatebirds. The spatial scale at which animals respond to atmospheric conditions is critical to understanding the evolution of flight strategies and long distance migrations. We studied three dimensional movements and energetics of frigatebirds and showed that they can stay aloft for months, making multiple trans-oceanic flights. To achieve this performance at an ocean-wide scale frigatebirds track the edge of the doldrums to take advantage of favorable wind and strong convection. At a small scale they use a roller-coaster flight relying on thermals and wind to soar within a 50-600 m altitude band under cumulus clouds and then glide at low costs over kilometers. Birds regularly soar inside cumulus clouds to use strong updraft occurring, and reach altitudes of 4000m where freezing conditions occur. With their extreme movement strategy frigatebirds encounter several atmospheric challenges that make them very susceptible to climate variability. [more]

Our laboratory studies the neurobiology of behavior in Drosophila melanogaster, with a strong emphasis on sleep. In particular, we are trying to uncover the still mysterious function(s) of sleep, using a systems neuroscience approach. The talk will present some of the most recent data of the lab as paradigmatic of what flies can teach us about sleep: using a machine-learning based video-tracking technology, we conducted a detailed high-throughput analysis of sleep in the fruit fly Drosophila melanogaster, coupled with a life-long chronic and specific sleep restriction. Our results show that some wild-type flies are virtually sleepless in baseline conditions and that complete, forced sleep restriction is not necessarily a lethal treatment in wild-type Drosophila melanogaster. We also show that circadian drive, and not homeostatic regulation, is the main contributor to sleep pressure in flies. We propose a three-partite model framework of sleep function, according to which, total sleep accounts for three components: a vital component, a useful component, and an accessory component. [more]

For details please see March 12, 2020! [more]

During active (REM) sleep in mammals and birds, skeletal muscles twitch throughout the body, causing jerky movements of limbs, whiskers, wings, and eyes. These spontaneous, discrete movements are particularly prominent during the perinatal period, when active sleep predominates. As demonstrated in newborn rats, the triggering of a twitch is followed by a cascade of sensory feedback (reafference) through the sensorimotor system, resulting in coherent oscillatory activity in such structures as sensorimotor cortex, hippocampus, and red nucleus. Critically, whereas these coherently organized oscillations are apparent when pups are asleep, they are nearly absent when they are awake. In light of the functional significance ascribed to brain oscillations for learning and plasticity, these findings suggest that active sleep provides a critical context for the expression of organized activity in cortical and subcortical structures, ultimately producing a brain that is functionally integrated with its body. [more]