(ORDO NEWS) — The new study is a step towards further understanding how dogs integrate olfactory stimuli into their cognitive functions.
A team of American scientists from the College of Veterinary Medicine at Cornell University, from the Department of Biology at Johns Hopkins University and Columbia University, received the first comprehensive evidence that the olfactory bulbs in dogs are directly related to other areas of the cerebral cortex, that is, the sense of smell of these animals is integrated into their cognitive functions.
The ability of dogs to recognize odors is 10,000 to 100,000 times better than the average human, with 300 million olfactory receptors compared to our 6 million.
The lower limit of volatile organic compounds detected by dogs is one part per trillion. They can even smell and detect a trillionth of a gram of explosive.
One of the main roles in this process is played by two olfactory bulbs weighing 60 grams each, that is, four times heavier than in humans.
They lie on the basal surface of the frontal lobes of the brain, have a rounded shape and a ventricle. It is in these formations that the initial processing of the odorous substance takes place.
While enough is known about the various functions of dogs’ sense of smell and how it can be beneficial , the structure of their olfactory system remains poorly understood. And the authors of the new work managed to take a step in studying this issue.
They examined 23 dogs of different sexes with moderately long and wide skulls (mesocephalic form). Non-invasive diffuse spectral tomography was used to map the connections between the olfactory bulbs and other areas of the cerebral cortex and mapped, after which the results were cross-checked with the Klingler white matter dissection method.
As a result, scientists have identified an extensive pathway – a chain of neurons – consisting of five tracts of white matter and connecting the olfactory bulbs with the occipital lobe (behind the parietal and temporal lobes, this is where the primary visual cortex is located), the cortical-spinal pathway, the limbic system, the piriformis lobes and entorhinal cortex , which is located in the temporal lobe and belongs to the hippocampal formation.
This probably explains why dogs, when entering a room, first of all begin to study it with the help of scent, and even blind individuals are surprisingly well oriented in space and their environment. In addition, identifying connections in the brain opens up new avenues for research.
“It makes you think that perhaps we also have a rudimentary connection between these two areas, because when we were more like monkeys, we were guided by smells,” the scientists concluded.
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