Even the tiniest of living things are capable of some amazing forms of locomotion, and some come with highly sophisticated sensor suites and manage to source their energy from the environment. Attempts to approach this sort of flexibility with robotics have taken two forms. One involves making tiny robots modeled on animal behavior. The other involves converting a living creature into a robot. So far, either approach has involved giving up a lot. You're either only implementing a few of life's features in the robot or shutting off most of life's features when taking over an insect.

But a team of researchers at Harvard has recognized that there are some behaviors that are so instinctual that it's possible to induce animals to act as if they were robotic. Or mostly robotic, at least—the fruit flies the researchers used would occasionally go their own way, despite strong inducements to stay with the program.

Smell the light

The first bit of behavior involved Drosophila's response to moving visual stimuli. If placed in an area where the fly would see a visual pattern that rotates from left to right, the fly will turn to the right in an attempt to keep the pattern stable. This allowed a projector system to "steer" the flies as they walked across an enclosure (despite their names, fruit flies tend to spend a lot of their time walking). By rotating the pattern back and forth, the researchers could steer the flies between two locations in the enclosure with about 94 percent accuracy.

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For many of us, memories of our childhood have become a bit hazy, if not vanishing entirely. But nobody really remembers much before the age of 4, because nearly all humans experience what's termed "infantile amnesia," in which memories that might have formed before that age seemingly vanish as we move through adolescence. And it's not just us; the phenomenon appears to occur in a number of our fellow mammals.

The simplest explanation for this would be that the systems that form long-term memories are simply immature and don't start working effectively until children hit the age of 4. But a recent animal experiment suggests that the situation in mice is more complex: the memories are there, they're just not normally accessible, although they can be re-activated. Now, a study that put human infants in an MRI tube suggests that memory activity starts by the age of 1, suggesting that the results in mice may apply to us.

Less than total recall

Mice are one of the species that we know experience infantile amnesia. And, thanks to over a century of research on mice, we have some sophisticated genetic tools that allow us to explore what's actually involved in the apparent absence of the animals' earliest memories.

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Human speech arises courtesy of some significant neural horsepower. Different areas of the brain are involved in determining the meaning that's desired, finding the words to express it, and then converting those words to a specific series of sounds—and all that comes before the correct sequence of nerve impulses is sent to the muscles that produce the final output. Humans are far from alone in the animal kingdom with an impressive range of vocalizations, though. That raises the prospect that we can understand a bit more about our own speech by studying how vocalization is managed in different animals.

One group of species that's especially interesting is birds. They're distant relatives compared to other animals with interesting vocal capabilities, like whales and elephants, and their brains have some notable differences from ours. They also show a range of behaviors, from complex songs to vocal mimicry to whatever it is that you want to call what parrots do. Thanks to a newly released study, however, we now have evidence that these different types of vocalization are the product of different control systems in the brain.

The study relied on electrodes placed in the brains of parrots and songbirds and tracked the behavior of neurons in a region that controls vocalization. It showed that the two relied on different types of control, with parrots having a system that operates similarly to the one used by humans.

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Our bodies rely on their lymphatic system to drain excessive fluids and remove waste from tissues, feeding those back into the blood stream. It’s a complex yet efficient cleaning mechanism that works in every organ except the brain. “When cells are active, they produce waste metabolites, and this also happens in the brain. Since there are no lymphatic vessels in the brain, the question was what was it that cleaned the brain,” Natalie Hauglund, a neuroscientist at Oxford University who led a recent study on the brain-clearing mechanism, told Ars.

Earlier studies done mostly on mice discovered that the brain had a system that flushed its tissues with cerebrospinal fluid, which carried away waste products in a process called glymphatic clearance. “Scientists noticed that this only happened during sleep, but it was unknown what it was about sleep that initiated this cleaning process,” Hauglund explains.

Her study found the glymphatic clearance was mediated by a hormone called norepinephrine and happened almost exclusively during the NREM sleep phase. But it only worked when sleep was natural. Anesthesia and sleeping pills shut this process down nearly completely.

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If you aren’t yet worried about the multitude of ways you inadvertently inflict suffering onto other living creatures, you will be after reading The Edge of Sentience by Jonathan Birch. And for good reason. Birch, a Professor of Philosophy at the London College of Economics and Political Science, was one of a team of experts chosen by the UK government to establish the Animal Welfare Act (or Sentience Act) in 2022—a law that protects animals whose sentience status is unclear.

According to Birch, even insects may possess sentience, which he defines as the capacity to have valenced experiences, or experiences that feel good or bad. At the very least, Birch explains, insects (as well as all vertebrates and a selection of invertebrates) are sentience candidates: animals that may be conscious and, until proven otherwise, should be regarded as such.

Although it might be a stretch to wrap our mammalian minds around insect sentience, it is not difficult to imagine that fellow vertebrates have the capacity to experience life, nor does it come as a surprise that even some invertebrates, such as octopuses and other cephalopod mollusks (squid, cuttlefish, and nautilus) qualify for sentience candidature. In fact, one species of octopus, Octopus vulgaris, has been protected by the UK’s Animal Scientific Procedures Act (ASPA) since 1986, which illustrates how long we have been aware of the possibility that invertebrates might be capable of experiencing valenced states of awareness, such as contentment, fear, pleasure, and pain.

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“If we go back to the early 1900s, this is when the idea was first proposed that memories are physically stored in some location within the brain,” says Michael R. Williamson, a researcher at the Baylor College of Medicine in Houston. For a long time, neuroscientists thought that the storage of memory in the brain was the job of engrams, ensembles of neurons that activate during a learning event. But it turned out this wasn’t the whole picture.

Williamson’s research investigated the role astrocytes, non-neuron brain cells, play in the read-and-write operations that go on in our heads. “Over the last 20 years the role of astrocytes has been understood better. We’ve learned that they can activate neurons. The addition we have made to that is showing that there are subsets of astrocytes that are active and involved in storing specific memories,” Williamson says in describing a new study his lab has published.

One consequence of this finding: Astrocytes could be artificially manipulated to suppress or enhance a specific memory, leaving all other memories intact.

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