Podcast with Mark Blumberg on rem sleep and twitching

What if the twitches you see in a sleeping infant are not remnants of dreams but a systematic self-calibration process for the developing motor system? Developmental neuroscientist Mark Blumberg explains how REM sleep twitching may serve as the brain's sonar , pinging muscles one at a time and listening for the sensory feedback that bootstraps the body map. Subscribe for more from the Convergent Science Network podcast series. Mark Blumberg joins Paul Verschure and Tony Prescott at the BCBT summer school to present his research on the relationship between sleep, twitching, and sensorimotor development in infant rats. During active (REM) sleep, neonatal rats produce highly discrete myoclonic twitches , brief activations of individual joints occurring against a background of low muscle tone. Blumberg argues these are not random byproducts but structured motor events with a high signal-to-noise ratio, ideally suited for the nervous system to map its own body. The sensory consequences of each twitch cascade through the brain in ways that wake movements do not, because during wakefulness a corollary discharge mechanism gates reafferent signals. The discussion traces the developmental trajectory of twitching from spinal-cord-driven activity in the fetus through brainstem contributions in the neonate, showing how the system becomes progressively more complex. Blumberg presents evidence that multi-joint twitches develop spatio-temporal structure over the first postnatal week, with certain movement combinations becoming more frequent and more organized , suggesting a selectionist process that shapes which movement patterns persist. He challenges the concept of motor primitives from a developmental systems perspective, arguing that no aspect of the motor system comes for free and that what appears primitive at one level is always a developmental product at another. Key topics include the distinction between REM sleep twitching and wake movement, how corollary discharge develops in early life, why the cortex appears uninvolved in producing twitches at early ages, the relationship between twitching and joint maintenance, and what the developmental perspective offers to robotics and motor control theory. Part of the Convergent Science Network podcast series from the BCBT Summer School.