Perhaps the most intricate organ in the human body, the brain is a sophisticated jumble of cells, chemicals, and electrical signals that coordinates our thoughts, actions, and involuntary bodily tasks.
This year, Live Science explored a variety of captivating studies regarding the brain, each unearthing new revelations about its functioning while simultaneously presenting additional queries.
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The male hormone cycle and the brain
Though seldom discussed, the male hormone cycle is considerably remarkable. Steroid hormones within the male body—including testosterone, cortisol, and estradiol—decrease by approximately 70% during the day and then reset during the night. A brain-imaging study conducted this year uncovered that the brain fluctuates in volume in alignment with this daily rhythm. At this stage, however, it remains unclear whether the hormones themselves instigate brain alterations or how this cycle influences male brain function.
Your brain on cinema
Numerous individuals often watch a movie when they wish to “switch off their brain” momentarily. However, a recent investigation revealed that, in fact, 24 distinct brain networks activate while viewing various genres of films. By correlating brain activity patterns with specific scenes, the researchers were able to compile the most precise functional brain map to date.
Transformation of babies’ brains after birth
An innovative study focusing on fetuses and infants reveals how the functions of particular areas of the brain abruptly change after birth. There is a significant surge in activity within the subcortical network, which serves as an information relay hub, and the sensorimotor network, which is responsible for processing external stimuli and coordinating movements. Researchers are now keen to investigate the same brain networks in preterm infants to determine if there is a significant variation from full-term infants.
The drive to eat
A straightforward circuit composed of only three varieties of neurons may underlie our urge to eat, according to a study. These neuronal cells collaborate to detect hunger-signaling hormones, ultimately triggering cells that govern the muscles used for chewing. By disrupting this circuit in laboratory mice, researchers induced the rodents to consume 12 times more food than typical and engage in chewing motions even in the absence of food.
Pregnancy’s “permanent etchings” on the brain
During pregnancy, approximately 80% of the brain’s gray matter diminishes in volume. Some of this lost volume reemerges after childbirth, but much of the absent matter remains lost. A comparable reduction in gray-matter volume is observed during puberty, a period when the brain is “pruning” away excess connections to enhance efficiency. Scientists propose that this alteration in pregnancy may represent a similar refinement of brain circuitry.
Three copies of each memory
A study involving mice indicates that the brain may retain at least three versions of each memory it encodes. These versions vary in their creation timing, duration, and flexibility over time. Grasping when and how these different copies materialize could assist scientists in tackling conditions that influence memory encoding and recall, such as PTSD and dementia.
Conscious lab-grown brains?
Is it possible for brain organoids—miniature brain models cultivated in the lab—to achieve consciousness? Live Science inquired this question to neuroscientist Kenneth Kosik, who assured us that it is improbable to occur in the near future. Nonetheless, he noted that there is still an ongoing discussion about what constitutes “consciousness.” Furthermore, major inquiries arise regarding what could transpire if human minibrains were transplanted into animals or connected to technologies to create purported cyborgs.
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‘Shrooms that “eliminate” sense of self
Psilocybin, the active compound found in magic mushrooms, could lead to the brain network tasked with preserving an individual’s sense of self losing sync. This network, known as the default mode network, is primarily active during self-reflection and when an individual is not focused on a specific endeavor. Under high doses of psilocybin, the network’s functioning temporarily altered, with some impacts lasting several weeks.
Source of psychosis
A brain-scanning investigation could assist in validating a hypothesis regarding the reasons individuals encounter psychosis, or abrupt disconnections from reality. Employing artificial intelligence (AI) for scan analysis, researchers identified overlapping “signatures” within the brains of individuals experiencing psychosis. These signatures were either linked to a genetic disorder or arose from an unidentified source. The results support a theory that, during psychosis, brain networks responsible for guiding a person’s focus malfunction, resulting in hallucinations and delusions.
“Universal” brain pattern among primates
Diverse primate species, including humans, exhibit a shared brain-wave pattern within the cerebral cortex, the brain’s outer layer. This common pattern features high-frequency brain waves in the upper cortex layers and slower waves in the deeper parts. Researchers speculate that the interaction between fast and slow waves determines which information remains in conscious awareness at any moment.
Flow state
Research unveiled the crucial regions of the brain that activate when an individual enters a flow state — or “being in the zone.” The investigation involved scanning the brains of musicians with varying levels of proficiency. It juxtaposed two competing theories of “flow,” with one emerging victorious.
Reading in a “blink”
A study indicated that the human brain can recognize the fundamental structures of written language within the duration of a blink. This implies the brain processes written expressions nearly as swiftly as it does visual images from our surroundings. Participants appeared to comprehend phrases with subjects, verbs, and objects faster than they did lists of nouns. They also quickly recognized when the meaning of a phrase was nonsensical. The results suggest that the brain not only registers the presence of words but also begins to interpret meaning immediately.
Large brains from gut microbes
A mouse investigation suggests that the remarkably large brains of humans might have developed partly due to the unique microbes residing in our intestines. Researchers transplanted microbes from the guts of humans and nonhuman primates into mice. The microbes sourced from humans and larger-brained primates transformed food into energy for the brain more efficiently than those from smaller-brained monkeys. The results imply that larger-brain microbes are more effective at converting food into brain energy, contributing to the organ’s development.
Breathtaking new brain map
Researchers from Harvard and Google revealed an astonishing map of a tiny portion of the human brain. It encompasses about 57,000 neurons, 9 inches (23 centimeters) of blood vessels, and 150 million synapses (the connection points among neurons). The map showcased distinct and surprising features of the brain, including enigmatic “whorls,” or knots, found in the outgoing wires of certain neurons.
3D-printed brain tissue that functions
In a groundbreaking first, scientists 3D printed operational human brain tissue. Instead of ink, the printer utilized stem cells, and the team subsequently employed a blend of chemicals to encourage those cells to develop into brain cells. The resultant cells were capable of communicating and forming networks akin to actual brain cells.
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