Tag Archives: in vivo

People who can’t form images in their mind have a surprising trait — they’re harder to spook with words

Are you easily spooked? Then you probably don’t have aphantasia, the inability to picture images into one’s mind. New research suggests that people who suffer from aphantasia show a reduced response to scary stories, suggesting that there’s a much stronger link between emotions and imagery than we assumed.

Image credits Shah Zaman Khan via Pixabay.

A study that pitted people against (made-up) distressing scenarios found that participants with aphantasia didn’t have much of a physical fear response to these situations, whereas the other participants did. The team says this is “the biggest difference” we’ve yet found between people with aphantasia and those without.

Fantasy no-fly zone

“These two sets of results suggest that aphantasia isn’t linked to reduced emotion in general, but is specific to participants reading scary stories,” says Professor Joel Pearson, senior author on the paper and Director of UNSW Science’s Future Minds Lab. “The emotional fear response was present when participants actually saw the scary material play out in front of them.”

“[This] suggests that imagery is an emotional thought amplifier. We can think all kinds of things, but without imagery, the thoughts aren’t going to have that emotional ‘boom’.”

“Aphantasia is neural diversity,” he adds. “It’s an amazing example of how different our brain and minds can be.”

The team measured each participant’s fear response through the changes in conductivity levels of their skin. This is influenced by how much a person sweats, and sweating is a physical reaction to states of fear or stress. It’s a commonly-used method of gauging an individual’s emotional state in psychology.

The study involved 46 participants, 22 of whom had aphantasia. Each participant was led to a darkened room, where they were seated and electrodes applied to their skin. That’s already kind of spooky, but then the participants were left alone, the lights were completely turned off, and a story was played in text form out on a screen for them.

In the beginning these were quite mundane, starting with scenarios such as “you are at the beach, in the water” or “you’re on a plane, by the window”. As they progressed, however, suspense was slowly mixed in. The participants were told of “dark flashes in the distant waves”, of “people on the beach pointing”, or the aircraft’s “cabin lights dimming” as the vehicle started to shake.

“Skin conductivity levels quickly started to grow for people who were able to visualize the stories,” says Prof Pearson. “The more the stories went on, the more their skin reacted.”

“But for people with aphantasia, the skin conductivity levels pretty much flatlined.”

Later on, the team also performed a control round in which the text stories were replaced with a series of scary or disturbing images, like a photo of a cadaver or a snake baring its fangs. This was meant to check whether the differences in response seen in the study were caused by aphanthasia, not by each participant’s threshold for response to fear. This time, the authors note, all participants showed a roughly equal physical response to the images.

According to Prof. Pearson, this is “the strongest evidence yet that mental imagery plays a key role in linking thoughts and emotions”, and “by far the biggest difference we’ve found between people with aphantasia and the general population” to date.

Aphanthasia affects an estimated 2-5% of the population, but it’s still very poorly understood. It seems to be associated with wide-ranging changes in other cognitive processes as well, most notably remembering, dreaming, and imagining. Not surprising, given that these activities often involve picturing events in your mind.

“This work may provide a potential new objective tool which could be used to help to confirm and diagnose aphantasia in the future,” says study co-author Dr Rebecca Keogh, a postdoctoral fellow formerly of UNSW and now based at Macquarie University, and it “supports aphantasia as a unique, verifiable phenomenon”. The authors say they got the idea for this study after noticing many members on aphantasia discussion boards mentioning that they don’t enjoy reading fiction.

Still, the team underscores that their results are based on averages, and that not every individual with aphantasia will experience it the same.

“Aphantasia comes in different shapes and sizes,” says Prof. Pearson. “Some people have no visual imagery, while other people have no imagery in one or all of their other senses. Some people dream while others don’t. “

“So don’t be concerned if you have aphantasia and don’t fit this mould. There are all kinds of variations to aphantasia that we’re only just discovering.”

The paper “The critical role of mental imagery in human emotion: insights from fear-based imagery and aphantasia” has been published in the journal Proceedings of the Royal Society B: Biological Sciences.

Scientists observe nanobots coordinating inside a living host for the first time

Nanobots have the potential of revolutionizing fields from material engineering to medicine. But first, we have to figure out how to build them and make them work. A new paper reports on a confident step toward that goal, as we’ve been able to observe the collective behavior of autonomous nanobots inside a living host.

A schematic of a molecular planetary gear, an example of nanomachinery. Image via Wikimedia.

The range of tasks that nanobots can potentially handle is, in theory, incredible. Needless to say, then, there’s a lot of interest in making such machines a reality. For now, however, they’re still in the research and development phase, with a particular interest in tailoring them for biomedical applications. Nanobots using our body’s own enzymes as fuel are some of the most promising systems in this regard currently, and a new paper is reporting on how they behave inside a living host.

March of the Machines

“The fact of having been able to see how nanorobots move together, like a swarm, and of following them within a living organism, is important, since millions of them are needed to treat specific pathologies such as, for example, cancer tumors,” says Samuel Sánchez, principal investigator at the Institute for Bioengineering of Catalonia (IBEC).

Nanobots are machines built at the nano-scale, where things are measured in millionths of a millimeter. They’re intended to be able to move and perform certain tasks by themselves, usually in groups. Being so small, however, actually seeing them go about their business — and thus, checking if they work as intended — isn’t very easy.

That’s why the IBEC team, together with members from the Radiochemistry & Nuclear Imaging Lab at the Center of Cooperative Investigation of Biomaterials (CIC biomaGUNE) in Spain, set out to observe these bots working inside the bladders of living mice using radioactive isotope labeling. This is the first time researchers have successfully tracked nanobots in vivo using Positron Emission Tomography (PET).

For the study, the team started with in vitro (in the lab) experiments, where they monitored the robots using both optical microscopy and PET. Both techniques allowed them to see how these nanoparticles interacted with different fluids and how they were able to collectively migrate following complex paths.

The next step involved injecting these bots into the bloodstream and, finally, the bladders of living mice. The machines were designed to be coated in urease, an enzyme that allows the bots to use urea from urine as fuel. The team reports that they were able to swim collectively, which induced currents in the fluid inside the animals’ bladders. These nanomachines were evenly distributed throughout the bladders, the team adds, which is indicative of the fact that they were coordinating as a group.

“Nanorobots show collective movements similar to those found in nature, such as birds flying in flocks, or the orderly patterns that schools of fish follow,” explains Samuel Sánchez, ICREA Research Professor at IBEC.

“We have seen that nanorobots that have urease on the surface move much faster than those that do not. It is, therefore, a proof of concept of the initial theory that nanorobots will be able to better reach a tumor and penetrate it,” says Jordi Llop, principal investigator at CIC biomaGUNE.

The findings showcase how nanomachines can come together and coordinate as a group, even one with millions of members, both in the lab and in living organisms. It might not sound like much, but checking that these machines can really interact as we want them to is a very important milestone in their development. It also goes a long way to prove that their activity can be monitored, even in living organisms, meaning that they can eventually be used to treat human patients.

“This is the first time that we are able to directly visualize the active diffusion of biocompatible nanorobots within biological fluids in vivo. The possibility to monitor their activity within the body and the fact that they display a more homogeneous distribution could revolutionize the way we understand nanoparticle-based drug delivery and diagnostic approaches,” says Tania Patiño, co-corresponding author of the paper.

One of the uses the team already envisions for similar nanobots is that of delivering drugs in tissues or organs where their diffusion would be hampered, either by a viscous substance (such as in the eye) or by poor vascularization (such as in the joints).

The paper “Swarming behavior and in vivo monitoring of enzymatic nanomotors within the bladder,” has been published in the journal Science Robotic.