What dreams do animals see?

“It has been observed that almost all animals, whether aquatic, aerial, or terrestrial, quite obviously fall into a state of sleep,” Aristotle wrote in his treatise On Sleep and Wakeness. But where do our lesser brothers go in their dreams?

Jason Goldman, a graduate student at the University of Southern California, Los Angeles, studies human and animal evolutionary psychology. The young scientist said that today there are two main ways to look into the consciousness of sleeping cats, birds and other living creatures. The first method is to observe the physical behavior of animals during various phases of the sleep-wake cycle. The second is to find out if their brains are functioning in a state of sleep similar to how our brains are functioning in that state.

We know from school biology lessons that during sleep, the brain goes through several periods with different levels of activity. One of them, with relatively reduced activity, was called slow sleep. The second, during which brain activity is almost the same as during wakefulness, was called the rapid phase, or REM-phase. At this time, the spinal cord sends powerful inhibitory impulses, paralyzing our entire body and making it impossible to move, talk or scream.

However, according to the International Classification of Sleep Disorders (ICDD), “during sleep, people can punch, kick, jump out of bed, and even run.” Such manifestations are usually consistent with dreams described after awakening.” For such people (and those who sleep next to them), injuries are not uncommon, but about the mass of dangers that lie in wait for “lunatics”, and there is no need to talk.

The same Greek philosopher we mentioned earlier argued in The History of Animals that since dogs sometimes bark in their sleep, they dream. This question became seriously interested in the 60s: by blocking neurons that send an order to paralyze all muscles into the spinal cord, scientists could freely observe the actions of cats and dogs in the process of dreaming. It turned out that the animals dream of actions usually performed by them in a waking state. They look for imaginary prey and attack it, defend their territory and escape from invisible enemies, etc.

Observing sleeper movements is not the only way to see their dreams. Today, researchers have more opportunities to study the electrical and chemical processes occurring in animal brain cells without harming them. Scientists from the Massachusetts Institute of Technology, Kenway Louis and Matthew Wilson, recorded the activity of neurons in the hippocampus of rats. This part of the brain is involved in the mechanisms of emotion formation and memory consolidation. Comparing the activity of the same neurons during wakefulness, when the rats ran through the maze, and during sleep, the scientists found almost no difference. In other words, in a dream, rats mentally ran through a familiar labyrinth – and it was not even difficult to determine the exact location of the sleeping rodent in its nooks.

Biologists from the University of Chicago, Amish Dave and Daniel Margoliash, found something similar in the study of the brain of zebra amadeins. These birds are born without genetically embedded models of singing: they have to learn their melodies. When the birds were awake, special neurons robutus archistriatalis in the part of their forebrain were excited, reacting to individual trills. The scientists were able to determine which cells were responsible for a particular note and were able to reconstruct the entire song from start to finish. They then examined the electrical activity of the brains of sleeping amadines and concluded that in sleep, birds loudly, note by note, rehearse their arias!

But do rats realize that they mentally run through their labyrinths while asleep? Do birds know that they hone the skill of singing in a dream? These questions are still difficult to answer – because even people rarely realize in a dream that they are asleep, no matter how absurd and implausible the plot – this is revealed only after waking up. Although we must admit that we are still the only ones who, after some training, are able to become aware of themselves within their own dreams and begin to control them at their own discretion.

Source: facepla.net