Episode 104: July 2026
This eLife episode explores trade-offs between body size and sperm production in gorillas, fever-driven changes in malaria-infected cells, the neuroscience of gambling machines, whether infants are predisposed to dance, and high-altitude adaptations in bird eggs.
Blurring the boundaries between neuroscience and organismal physiology
Work in my laboratory is based on the assumptions that we do not know yet how all physiological functions are regulated and that mouse genetics by allowing to identify novel inter-organ communications is the most efficient ways to identify novel regulation of physiological functions. We test these two contention through the study of bone which is the organ my lab has studied since its inception. Based on precise cell biological and clinical reasons that will be presented during the seminar we hypothesized that bone should be a regulator of energy metabolism and reproduction and identified a bone-derived hormone termed osteocalcin that is responsible of these regulatory events. The study of this hormone revealed that in addition to its predicted functions it also regulates brain size, hippocampus development, prevents anxiety and depression and favors spatial learning and memory by signaling through a specific receptor we characterized. As will be presented, we elucidated some of the molecular events accounting for the influence of osteocalcin on brain and showed that maternal osteocalcin is the pool of this hormone that affects brain development. Subsequently and looking at all the physiological functions regulated by osteocalcin, i.e., memory, the ability to exercise, glucose metabolism, the regulation of testosterone biosynthesis, we realized that are all need or regulated in the case of danger. In other words it suggested that osteocalcin is an hormone needed to sense and overcome acute danger. Consonant with this hypothesis we next showed this led us to demonstrate that bone via osteocalcin is needed to mount an acute stress response through molecular and cellular mechanisms that will be presented during the seminar. overall, an evolutionary appraisal of bone biology, this body of work and experiments ongoing in the lab concur to suggest 1] the appearance of bone during evolution has changed how physiological functions as diverse as memory, the acute stress response but also exercise and glucose metabolism are regulated and 2] identified bone and osteocalcin as its molecular vector, as an organ needed to sense and response to danger.
Spinners, not swimmers: how sperm flagella fooled us for 350 years - now in 3D!
In the 17th century, Antonie van Leeuwenhoek used one of the earliest microscopes to see how sperm swim. He described the sperm as a “living animalcule” with a “tail, which, when swimming, lashes with a snakelike movement, like eels in water”. Strikingly, this perception of how sperm moves has not changed since. Indeed, anyone today with a modern microscope would make the same observation: sperm swim forward by wiggling their tail symmetrically side-to-side. Our new research using 3D microscopy shows that we have all been victims of a sperm deception, an illusion. Only now we can see that for 350 years we have been wrong about how sperm actually swims.