These studies also showed that the human brain is not exceptional in its cellular composition, as it was found to contain as many neuronal and non-neuronal cells as would be expected of a primate brain of its size. However, our recent studies using a novel method to determine the cellular composition of the brain of humans and other primates as well as of rodents and insectivores show that, since different cellular scaling rules apply to the brains within these orders, brain size can no longer be considered a proxy for the number of neurons in the brain. Such uniqueness was seemingly necessary to justify the superior cognitive abilities of humans over larger-brained mammals such as elephants and whales.

'Rapid stimulus-evoked astrocyte Ca2+ elevations and hemodynamic responses in mouse somatosensory cortex in vivo', PNAS (2013), DOI: 10.1073/pnas.The human brain has often been viewed as outstanding among mammalian brains: the most cognitively able, the largest-than-expected from body size, endowed with an overdeveloped cerebral cortex that represents over 80% of brain mass, and purportedly containing 100 billion neurons and 10× more glial cells.

Read the Danish version of this article at videnskab.dk Scientific links ”It is too early to say whether astrocytes actually play a direct role in mental phenomena, but our findings suggest that it is very likely,” says Lind. In fact, the assumption that astrocytes respond slowly has been so strong that when scientists have observed a quick response from the astrocytes, this has been attributed to noise in the measurements.Īlthough the new study shows that astrocytes respond more quickly than previously assumed, there is room for a lot more research in this area: ”It is a challenge to convince other researchers that this study is solid and that astrocytes could actually be a much more significant component of brain function than we thought.” It has been a strongly-held belief in research circles that astrocytes do not play a major role in brain signalling: ”It is starting to look as if the astrocytes can respond quickly and possibly be directly involved in our mental functions.” However, other studies have indicated that the quick response of the astrocytes also takes place in the cerebellum and the hippocampus, which are associated with memory. This study focused on the cerebral cortex, the area of the brain responsible for the higher cognitive functions. It is too early to say whether astrocytes actually play a direct role in mental phenomena, but our findings suggest that it is very likely.

Are neurons only in the brain