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November 21 (UPI) – The way neurons treat information depends on their positioning in the cortex, according to a new study by researchers at the University of Queensland.
Until now, neuroscientists have agreed that microcircuits of neurons in the outermost layer of the brain, the cortex, function and interact in a standardized way. Scientists thought miniature circuits were more or less the same.
But some researchers were skeptical. To determine whether the same types of neurons performed the same functions, regardless of their location, scientists from the University of Queensland undertook to measure the influence of the structural features of the cortex on neural patterns.
The new survey revealed a surprising level of structural variety in the cortex. The researchers discovered that the cortex gradually thickens from the back of the brain to the front. Scientists also measured the variety of thickness within a single functional area of the brain.
Further investigation has shown that the thickness of the cortex changes the shape of individual neurons. In the thicker parts of the cortex, the neurons are elongated.
When scientists examined how neurons of different lengths work, they found that their shape changed the way neurons treat information.
To interpret the information, most neurons not only receive information about sensory experiences, but they must also compare this information to an internally generated model of the world. Thus, some neurons must be able to process two sets of inputs.
The researchers discovered that longer neurons are able to do just that. Shorter neurons, even the same types of neurons, were not able to process two sets of inputs. Shorter neurons had only one integration area for processing sensory data.
The tests showed how the information processed by a neuron depended on its position in the cortex.
"It turns out that they work quite differently," Stephen Williams, a Queensland professor, said in a press release. "Electrically, they are even more distinct than we thought."
The researchers described their discovery this week in the journal Neuron.
"Our work demonstrates that the thickness of the neocortex governs not only the anatomical structure of neurons, but also their electrical properties," said researcher Lee Fletcher. "The results reveal the complexity of the computer strategies used in the neocortex and suggest that it is composed of flexible circuits in terms of calculation."
In future studies, scientists hope to determine the impact of neuronal differences on cognition and behavior.
The authors of the new study believe that differences may explain why rodents respond differently to similar but slightly different stimuli. Mice, for example, respond more quickly to stimuli from above, like passing shadows.
Shorter neurons can treat sensory information more effectively when an immediate reaction is needed, such as hurrying to shelter when the shadow of an owl passes overhead. their head. Fighting or trailing stimuli do not need to be integrated and compared to an internal model.
"The treatment of information may not be useful in such a system, but rather an instinctive reaction," said Williams. "To detect and react to predators, a wired system that works efficiently and very quickly can be a survival value, so these small neurons are hypersensitive to incoming inputs."
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