Speaker 1: Welcome to brain Stuff production of I Heart Radio. Hey
Speaker 1: brain Stuff. Lauren Vogelbaum here with a classic episode from
Speaker 1: former host Christian Sagar. In this one, we dip into
Speaker 1: questions about sleep. We humans sometimes have a strange relationship
Speaker 1: with sleep, but what about other animals and specifically, what
Speaker 1: about animals that are very different from us? Is a
Speaker 1: brain necessary for sleep? Hey brain Stuff, it's Christian Sagar.
Speaker 1: You probably don't think you have much in common with
Speaker 1: a jellyfish. After all, their species don't share elemental properties
Speaker 1: with you, like you know, a spine or a brain,
Speaker 1: or even the same interests. The primitive jellyfish in the
Speaker 1: genus Cassiopeia spends its time resting upside down on the
Speaker 1: ocean floor, rather than you know, waiting for the next
Speaker 1: season of Game Thrones. Researchers, though, have now discovered that
Speaker 1: you and old Cassiopea are more like than anyone might
Speaker 1: have spected. You both begin and end your days with
Speaker 1: a little shut eye. Yes, jellyfish sleep. The study was
Speaker 1: published online in the September edition of the journal Current Biology.
Speaker 1: Unlike most jellyfish, Cassiopeia jellyfish often rest on the floor
Speaker 1: of mangrove swamps and seagrass beds and rarely move from
Speaker 1: their underwater spots. By lying upside down, the jellyfish exposes
Speaker 1: the algae on its underside to the sun, allowing it
Speaker 1: to photosynthesize and live off the food the algae produces.
Speaker 1: Ravi Nath, the papers co first author and a graduate
Speaker 1: student in cal texts Sternberg Laboratory, says that it may
Speaker 1: not seem surprising that jellyfish sleep, after all, mammals sleep,
Speaker 1: and other invertebrates such as worms and fruit flies sleep,
Speaker 1: but Nath points out that jellyfish are the most evolutionary
Speaker 1: ancient animals known to sleep. This finding opens up many
Speaker 1: more questions, is sleep the property of neurons? And perhaps
Speaker 1: a more far fetched question, do plant sleep? To test
Speaker 1: whether the jellyfish were actually sleeping, researchers set up cameras
Speaker 1: and found the jellyfish were largely inactive at night, and
Speaker 1: they pulsed less during the day about thirty nine times
Speaker 1: compared to fifty eight times during sunlit hours. Then the
Speaker 1: team discovered it was harder to rouse the jellyfish at
Speaker 1: night too. They set up a false bottom within the
Speaker 1: jellyfish tank and pulled the platform out from under the jellyfish.
Speaker 1: When alert during the day, the jellyfish immediately swam to
Speaker 1: the bottom of the tank. At night, however, it took
Speaker 1: several seconds for the jellyfish to awake before heading to
Speaker 1: the tank floor. The researchers also demonstrated that sleep is
Speaker 1: essential to jellyfish, just like it is to people. After
Speaker 1: keeping the jellyfish awake during the night with pulses of water,
Speaker 1: the jellyfish were slosh and sleepy the next day, when
Speaker 1: they otherwise would have been active. Mondays am i right.
Speaker 1: The discovery that jellyfish sleep could be an important next
Speaker 1: step in sleep research for all types of species. While
Speaker 1: the basis and function of sleep is still a mystery
Speaker 1: to scientists, it's often associated with the brain because sleep
Speaker 1: has a profound impact on memory and learning. Jellyfish don't
Speaker 1: need a brain to sleep, which could be a revolutionary
Speaker 1: concept for sleep science. Today's episode was written by Loaurel
Speaker 1: Dove and produced by Tristan Neil and Tyler Playing. For
Speaker 1: more in this and lots of other curious topics, visit
Speaker 1: how stuff works dot com. Brain Stuff is a production
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