Saturday Citations: Octopus behavior; children's nightmares; the fast effects of meditation

Chris Packham

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Robert Egan

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Happy Saturday! This week, researchers reported on the familiar phenomenon of speeding away from a slower-driving car only to have it catch up at the next traffic light—they've named it Voorhees law, after the well-known movie slasher who always catches up to his victims. A study finds that nonpsychotropic cannabinoid CBD reverses brain damage in a mouse model of Alzheimer's disease. And scientists are testing methods to regrow joints damaged by arthritis.

Meanwhile, researchers timed how quickly meditation induces changes in brain waves; Japanese biologists reported that male octopuses are extremely reluctant to use their reproductive limb in nonreproductive activities; and psychologists have developed an approach to help children with recurrent nightmares.

Speed meditation

Researchers have pursued the neurological effects of meditation for many years, and changes in the frontal and parietal brain regions are well documented. However, it has been unclear how quickly these changes occur during meditation, as well as the differences between experienced and novice meditators. An international research collaborative recently designed a study to clarify this question, recruiting three groups of volunteers: people with no meditation experience, novice meditators, and experienced practitioners. The volunteers wore caps equipped with sensors to record electrical activity in the brain during meditation.

They found that across the groups, the brain shifts its electrical pattern within two to three minutes, switching from a normal state to a state of relaxed alertness characterized by alpha and theta waves, associated with calmness and focus, and beta 1 waves, associated with engaged focus. While the experienced meditators took about the same amount of time to reach this state, their brain waves were significantly stronger than the other groups. Additionally, they exhibited a distinct brainwave signature absent in the other groups that began to appear around 30 seconds after the beginning of meditation. The researchers suggest that even brief periods of meditation of seven minutes or more could provide benefits to beginners.

Eight, but seven if you're nasty

Octopuses can regenerate lost limbs, but males have one particular limb that they'll take extraordinary measures to protect. They use the hectocotylus, their third right arm, to transfer sperm to females during mating. According to a new study in Ethology by Japanese researchers, about 80% of octopuses in the wild lose limbs, but female octopuses are significantly more likely to lose their third right arm than males, which are observed to keep that arm tucked away.

In the first experiment, they presented octopuses in the lab with an unfamiliar object, a lead weight. Female pygmy octopuses would use all eight limbs to explore it. Males, however, used only seven of their limbs, avoiding the use of their reproductive arm. In a second experiment, the researchers placed a piece of shrimp inside a dark hole that the octopuses could not explore visually. Males generally used their seven nonreproductive limbs to explore the hole before venturing their reproductive limb inside, which suggests flexibility in the use and protection of the third right arm.

The authors of the study write, "These results strongly suggest that O. parvus males protect R3 arms, the copulatory apparatus, under situations with unpredictable risks."

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Little nightmares

Children often have recurrent nightmares that persist over time, and to date, there hasn't been a therapeutic approach specifically geared to give them control. Researchers from the University of Oklahoma and the University of Tulsa have now developed a model called DARC-NESS that addresses the mechanisms of factors that maintain nightmares and help children to break the cycle.

Lisa Cromer, professor of psychology at the University of Tulsa, says, "It's a child's response to a nightmare that causes the chronic nightmares to happen, which means if we can learn to respond to nightmares differently, then we can interrupt that cycle. It's empowering to understand that we can take steps to master our dreams."

The model focuses beyond the content of the nightmare to encompass the child's interpretation, their worries about sleeping, anxiety at bedtime, and how the child copes after waking from a nightmare. This information helps clinicians and parents to design a personalized treatment plan—for some children, reducing anxiety at bedtime is a direct treatment; other children may need improved sleep habits or exposure-based therapy that includes describing, writing, and creating art based on their nightmares.

Cromer says, "Self-efficacy is at the heart of the model. When children feel empowered to do something about the nightmares, they begin to see how things are interconnected—because they're sleeping better, they have more energy, they go to school more consistently, and their parents report improved behavior."

Written for you by our author Chris Packham, edited by Gaby Clark, and fact-checked and reviewed by Robert Egan—this article is the result of careful human work. We rely on readers like you to keep independent science journalism alive. If this reporting matters to you, please consider a donation (especially monthly). You'll get an ad-free account as a thank-you.

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