PT  - JOURNAL ARTICLE
AU  - Erica F. Andrews
AU  - Raluca Pascalau
AU  - Alexandra Horowitz
AU  - Gillian M. Lawrence
AU  - Philippa J. Johnson
TI  - Extensive Connections of the Canine Olfactory Pathway Revealed by Tractography and Dissection
AID  - 10.1523/JNEUROSCI.2355-21.2022
DP  - 2022 Jul 11
TA  - The Journal of Neuroscience
PG  - JN-RM-2355-21
4099  - http://www.jneurosci.org/content/early/2022/07/06/JNEUROSCI.2355-21.2022.short
4100  - http://www.jneurosci.org/content/early/2022/07/06/JNEUROSCI.2355-21.2022.full
AB  - The domestic dog’s olfactory sense is widely recognized as being highly sensitive with a diverse function, however, little is known about the structure of their olfactory system. This study examined a cohort of mixed sex mesaticephalic canines and used Diffusion MRI (DTI), to map connections from the olfactory bulb to other cortical regions of the brain. The results were validated using the Klingler dissection method. An extensive pathway composed of five white matter tracts connecting to the occipital lobe, cortical spinal tract, limbic system, piriform lobe and entorhinal pathway was identified. This is the first documentation of a direct connection between the olfactory bulb and occipital lobe in any species and is a step towards further understanding how the dog integrates olfactory stimuli in their cognitive function.Significance StatementThe highly sensitive olfactory system of the domestic dog is largely unexplored. We applied diffusion tractography and dissection techniques to evaluate the white matter connections associated with the olfactory system in a large cohort of dogs. We discovered an extensive white matter network extending from the olfactory bulb to form novel connections directly to other cortices of the brain. This is the first documentation of these novel olfactory connections and provides new insight into how the dog integrates olfactory stimuli in their cognitive functioning.