Exercise maintains brain size, new research finds
Aerobic exercise can improve memory function and maintain brain health as we age, a new Australian-led study has found.
Nov 13, 2017
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Aerobic exercise can improve memory function and maintain brain health as we age, a new Australian-led study has found.
Nov 13, 2017
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The English idiom "highbrow," derived from a physical description of a skull barely able to contain the brain inside of it, comes from a long-held belief in the existence of a link between brain size and intelligence.
Nov 30, 2018
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(Medical Xpress)—Complex human brain tissue has been successfully developed in a three-dimensional culture system established in an Austrian laboratory. The method described in the current issue of Nature allows pluripotent ...
Aug 28, 2013
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A team of researchers at Neurochlore, Ben-Ari Institute of Neuroarcheology has found evidence suggesting that the birth process itself may play a role in the development of autism spectrum disorder (ASD) in some people. In ...
One of the world's largest studies on the impact of cholesterol-lowering medication has highlighted an issue with a new class of drugs that could impair lung function in some patients.
Jul 20, 2023
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(Medical Xpress) -- Researchers at Duke University Medical Center have found an apparent correlation between religious practices and changes in the brains of older adults.
May 19, 2011
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(Medical Xpress) -- When it comes to intelligence, what factors distinguish the brains of exceptionally smart humans from those of average humans?
Aug 1, 2012
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A new study from Macquarie University has found that people's perception of their own and other people's body weight can change in as little as two minutes.
Jul 8, 2016
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Patients in a new Northwestern Medicine study were able to comprehend words that were written but not said aloud. They could write the names of things they saw but not verbalize them.
Mar 21, 2019
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The largest ever study of the genetics of the brain—encompassing some 36,000 brain scans—has identified more than 4,000 genetic variants linked to brain structure. The results of the study, led by researchers at the University ...
Aug 17, 2023
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There has been quite a bit of study of the relationships between brain size, body size, and other variables across a wide range of species, largely because the easiest way to study any object is to measure its size. Even for extinct species brain size can be estimated by measuring the cavity inside the skull. The story that emerges, however, is complex.
As might be expected, brain size tends to increase with body size (measured by weight, which is roughly equivalent to volume). The relationship is not a strict proportionality, though: averaging across all orders of mammals, it follows a power law, with an exponent of about 0.75. There are good reasons for expecting a power law: for example, the body-size-to-body-length relationship follows a power law with an exponent of 0.33, and the body-size-to-surface-area relationship a power law with an exponent of 0.67. The explanation for an exponent of 0.75 is not obvious—however it is worth noting that several physiological variables appear to be related to body size by approximately the same exponent, for example, the basal metabolic rate. This power law formula applies to the "average" brain of mammals taken as a whole, but each family (cats, rodents, primates, etc) departs from it to some degree, in a way that generally reflects the overall "sophistication" of behavior. Primates, for a given body size, have brains 5 to 10 times as large as the formula predicts. Predators tend to have relatively larger brains than the animals they prey on; placental mammals (the great majority) have relatively larger brains than marsupials such as the opossum.
When the mammalian brain increases in size, not all parts increase at the same rate. In particular, the larger the brain of a species, the greater the fraction taken up by the cortex. Thus, in the species with the largest brains, most of their volume is filled with cortex: this applies not only to humans, but also to animals such as dolphins, whales, or elephants.
The evolution of homo sapiens over the past two million years has been marked by a steady increase in brain size, but much of it can be accounted for by corresponding increases in body size. There are, however, many departures from the trend that are difficult to explain in a systematic way: in particular, the appearance of modern man about 100,000 years ago was marked by a decrease in body size at the same time as an increase in brain size. Even so, it is notorious that Neanderthals, which went extinct about 40,000 years ago, had larger brains than modern homo sapiens.
Not all investigators are happy with the amount of attention that has been paid to brain size. Roth and Dicke, for example, have argued that factors other than size are more highly correlated with intelligence, such as the number of cortical neurons and the speed of their connections. Moreover they point out that intelligence depends not just on the amount of brain tissue, but on the details of how it is structured.
This text uses material from Wikipedia, licensed under CC BY-SA