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The adult human brain weighs on average about 1.2–1.4 kg (2.6–3.1 lb) which is about 2% of the total body weight, [2] [3] with a volume of around 1260 cm 3 in men and 1130 cm 3 in women. [4] There is substantial individual variation, [ 4 ] with the standard reference range for men being 1,180–1,620 g (2.60–3.57 lb) [ 5 ] and for women ...
Brain size. The size of the brain is a frequent topic of study within the fields of anatomy, biological anthropology, animal science and evolution. Measuring brain size and cranial capacity is relevant both to humans and other animals, and can be done by weight or volume via MRI scans, by skull volume, or by neuroimaging intelligence testing.
[53] [54] Considering that the volume of the modern human brain is around 1,352 cm 3 on average this represents a substantial amount of brain mass evolved. [55] Australopiths are estimated to have a total neuron count of ~30-35 billion. [49]
Brain cells make up the functional tissue of the brain. The rest of the brain tissue is the structural stroma that includes connective tissue such as the meninges , blood vessels , and ducts. The two main types of cells in the brain are neurons , also known as nerve cells, and glial cells , also known as neuroglia. [ 1 ]
In adult humans the volume of the hippocampus on each side of the brain is about 3.0 to 3.5 cm 3 as compared to 320 to 420 cm 3 for the volume of the neocortex. [ 154 ] There is also a general relationship between the size of the hippocampus and spatial memory.
Brain–body mass ratio. Brain–body mass ratio, also known as the brain–body weight ratio, is the ratio of brain mass to body mass, which is hypothesized to be a rough estimate of the intelligence of an animal, although fairly inaccurate in many cases. A more complex measurement, encephalization quotient, takes into account allometric ...
Gyrification in the human brain. Gyrification is the process of forming the characteristic folds of the cerebral cortex. [1] The peak of such a fold is called a gyrus (pl. gyri), and its trough is called a sulcus (pl. sulci). The neurons of the cerebral cortex reside in a thin layer of gray matter, only 2–4 mm thick, at the surface of the ...
Up to 36% of variance in verbal intelligence can be explained by brain volume, while only approximately 10% of variance in visuospatial intelligence can be explained by brain volume. [9] A 2015 study by researcher Stuart J. Ritchie found that brain size explained 12% of the variance in intelligence among individuals. [ 21 ]