Jul 172012

The brain of the domestic dog (Canis Lupus familiaris) is an evolutionary curiosity, structurally intermediate between both rodents and humans. The canine brain features a complex cortical gyral and sulcal folding pattern that is very similar to that seen in humans, whilst the rodent cortex is smooth. Additionally, dogs possess dentate gyral areas in both the dorsal (rodent-like) and ventral (human-like) forebrain (A).

Hippocampal neurogenesis occurs in several mammalian species, however, the rate of proliferative turnover is less frequent in adult humans compared to rodents. These inter-species differences may reflect intrinsic dorsal versus ventral hippocampal neural precursor differences, and so the canine brain presents an opportunity to test this hypothesis within the one species.

To determine whether there is an increased incidence of neurogenic associated features in the dorsal canine hippocampus compared to the ventral, we employed both histological staining and neural colony forming cell assays.

Newly post-mortem hippocampal canine tissue was isolated, dissociated and suspended in a semi-solid collagen matrix.  By eliminating the possibility of cell fusion, neural precursors could be easily identified and proliferative potential quantified.  Interestingly, a greater number of larger colonies were observed in dorsal hippocampal isolates, thus, the neural colony forming assay is suggestive of increased proliferation rates in the dorsal canine hippocampus (B).  Current efforts are directed at characterising these hippocampal isolates, in attempts to further understand this observed phenomenon.