Human Cognition Explored Using Chandelier Cells

Thanks
to research regarding the neurocortex's organization and function,
scientists may have learned more about the nature of human cognition,
according to an article released on September 1, 2008 in the
open-access journal PLoS Medicine.



The neocortex is the
part of the brain that takes responsibility for sensory perceptions,
conscious thought, and language. Humans have a neocortex that is
considerably larger than that of other mammals, making it an ideal
target for research on human cognition, which relates these skills.



Several
theories exist regarding human cognition. For instance, some believe
that the higher level of cognition present in humans is due to the
larger size and greater complexity of the neocortex. In another
theory,В different types of cells in the neocortex, which other
mammals do not
have, are responsible for our higher levels of cognition. Chandelier
cells, which are shaped like candlesticks, are of particular interest
to the authors of this study. While other species have these cells,
they tend to be more complex in humans. Therefore, they might be
responsible for humans' higher levels of cognition thanks to a more
complicated or differently organized system of communication.



By recording impulses from pairs of connected neurons in human brain
tissue, these authors were able to examine the microcircuitry of cells
in the neocortex. By measuring the dynamic communication between
neurons, they could observe the methods of interaction between the
cells. Notably, while previously scientists thought that neurons worked
in groups, but according to this study a single chandelier cell could
trigger multiple cells in the cortex to cause a chain reaction in the
brain.



Using this sequence of events, a precisely timed chain of electrical
events could be triggered in the neocortex. Also, in humans, the
synaptic pathways, which link between chandelier and other cells, are
much stronger than recorded in other mammals. This suggests that the
cells humans have are indeed different, and this could be the reason
for the higher levels of cognition they obtain. The results of this
study further push to create more questions about how and why our
brains are different from other species'.



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Complex events initiated by individual spikes in the human
cerebral cortex.

MolnГЎr G, OlГЎh S, KomlГіsi G, FГјle M, Szabadics J, et al.

PLoS Biol 6(9): e222.

doi:10.1371/journal.pbio.0060222

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Written by Anna Sophia McKenney