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Sleep deprivation had disturbed my vestibular system, making me feel drifting or floating, and had especially interfered with my right TPJ and with it my body schema (Chee & Chua 2007, Quarck et al 2006). Nearly four hours of holding out my arm for the Ouija board had confused my body schema even more. My attention kept wandering and my short term memory was reduced by cannabis (Earleywine 2002).

With my hyperexcitable cortex (Braithwaite et al 2013) already disinhibited by the combination of sleep deprivation and cannabis, it went into random firing, producing an illusory central light and the form constants of spirals and tunnels (Cowan 1982). Disinhibited motion detectors produced illusory movement and as the light grew bigger I seemed to move towards it

My auditory cortex was similarly hyperactive, producing random low-frequency repetitive sounds that drowned out the music. It sounded to me like the pounding of horses’ hooves. I was galloping fast down the tunnel towards the light.

People have a tendency to interpret new information in a way that supports their pre-existing beliefs, a phenomenon known as confirmation bias.

Now, researchers reporting in Current Biology on September 13 have shown that people will do the same thing even when the decision they've made pertains to a choice that is rather less consequential: which direction a series of dots is moving and whether the average of a series of numbers is greater or less than 50.

"Confirmation biases have previously only been established in the domains of higher cognition or subjective preferences," for example in individuals' preferences for one consumer product or another, says Tobias Donner from University Medical Center Hamburg-Eppendorf (UKE), Germany. "It was rather striking for us to see that people displayed clear signs of confirmation bias when judging on sensory input that we expected to be subjectively neutral to them."

In an extensive 2012 literature review, the psychologist Matthew Merced notes that, even though nobody knows for certain why we dream, advances in the technology and techniques of brain research have at least helped explain how we dream. Humans, at least, dream a lot, multiple times a night, and the brain is very active during dream periods. Dreaming must be important, even if it remains mysterious.

Early dreaming studies were, frankly, pretty primitive. Researchers would wait for the Rapid Eye Movement (REM) sleep to begin, then wake the subject up and ask about any dreams. Dreaming occurs during non-REM (NREM) sleep as well, but those dreams tend to be less vivid. Now, thanks to PET scans, it is known that large areas of the brain, covering such functions as motor control and sensory processing, all become active during dreams. Chemical changes occur as well, especially during REM: acetylcholine, a neurotransmitter that fires up the brain and forces muscles to contract, ramps up production. Unsurprisingly, areas of the brain controlling awareness and consciousness remain dormant.

Assuming there is a purpose, natural selection suggests that dreaming must provide some sort of survival benefit. Why spend energy on involuntary movements and brain activation if nothing is being achieved? One possibility is that dreams are kind of a virtual reality world, a space where humans can safely practice coping with threats (being chased, for example, is pretty common). REM sleep and dreaming may also help process important or traumatic memories. Finally, there is a theory that dreams are a way for the brain to rid itself of information it isn’t using, a sort of “psychic disk cleanup.” According to Merced, any of these explanations could be correct. Sweet dreams to all, humans and octopuses alike!

immune cells from the periphery routinely patrol the central nervous system and support its function. In a new study, researchers showed for the first time that—just as the brain remembers people, places, smells, and so on—it also stores what they call “memory traces” of the body’s past infections. Reactivating the same brain cells that encode this information is enough to swiftly summon the peripheral immune system to defend at-risk tissues.

It is clear the peripheral immune system is capable of retaining information about past infections to fight off future ones—otherwise, vaccines would not work. But Asya Rolls, a neuroimmunologist at Technion–Israel Institute of Technology and the paper’s senior author, says the study expands this concept of classical immunologic memory. Initially, she was taken aback that the brain could store traces of immune activity and use them to trigger such a precise response. “I was amazed,” she says.

After the infection and immune response dissipated, the researchers injected the mice with a drug that artificially reactivated those same groups of brain cells. They were stunned by what they saw: upon reactivation, the insular cortex directed the immune system to mount a targeted response in the gut at the site of the original inflammation—even though, by that time, there was no infection, tissue damage or pathogen-initiated local inflammation to be found. The brain had retained some sort of memory of the infection and was prepared to reinitiate the fight.

Andy Clark admits it’s strange that he took up “predictive processing,” an ambitious leading theory of how the brain works. A philosopher of mind at the University of Sussex, he has devoted his career to how thinking doesn’t occur just between the ears—that it flows through our bodies, tools, and environments. “The external world is functioning as part of our cognitive machinery

But 15 years ago, he realized that had to come back to the center of the system: the brain. And he found that predictive processing provided the essential links among the brain, body, and world.

There’s a traditional view that goes back at least to Descartes that perception was about the imprinting of the outside world onto the sense organs. In 20th-century artificial intelligence and neuroscience, vision was a feed-forward process in which you took in pixel-level information, refined it into a two and a half–dimensional sketch, and then refined that into a full world model.

It’s tough out there for a mouse

Mice compensate with sharp senses of sight, hearing and smell. But they may have another set of tools we’ve overlooked. A paper published last week in Royal Society Open Science details striking similarities between the internal structures of certain small mammal and marsupial hairs and those of man-made optical instruments.

Over the years, he has developed an appreciation for “how comfortable animals are in complete darkness,” he said. That led him to wonder about the extent of their sensory powers.

Though Pamuk is playful where Tolstoy is strident, behind all the beautiful descriptions of Mingherian flowers and mountains of rose-colored marble, he is undeniably making an argument. If Tolstoy’s great theme in War and Peace is the powerlessness of humanity to remake the world through acts of will alone, Pamuk’s is the role of accident in shaping history and its writing. Tolstoy’s enemy was Napoleon, the embodiment of modernity’s hubris. Pamuk’s is the historiographic crimes of nationalism.

Mingheria becomes independent not only through the great accident of the plague, but also through thousands of tiny accidents at crucial moments. The problem with nations, the book suggests, is that they take all these small instances in which things could just as well have been otherwise and cast them as a monumental inevitability. Once a nation-state comes into existence, the machinery of education and civic ritual and the instruments of propaganda and state violence are wielded to turn chance into fate. And that fate becomes inexorable.

This is a bold thing to say in Turkey, a country that has gone to great lengths to promulgate a heroic and highly sanitized account of its founding. It is even bolder when one notes that Mingheria’s struggle for independence, and its troubled post-independence history, function very well as an allegory of Turkey itself. Major Kâmil is, like Mustafa Kemal Atatürk, an Ottoman war hero and secularist who tries to found a country divided by ethnic and religious rivalries on a conception of linguistic and ethnic nationalism.