Leszek Rychlik (Department of Systematic Zoology) and co-authors (mainly from the Nencki Institute of Experimental Biology PAS in Warsaw) published, in the International Journal of Molecular Science, the results of a study in which they checked whether the numbers of new generated cells in shrew brains (namely in the subventricular zone of the lateral ventricle, SVZ, the olfactory bulb, OB, and the dentate gyrus of the hippocampal formation, DG) depend on their brain size. The authors examined two medium-sized species, Crocidura russula and Neomys fodiens (mean body mass: 13.5 and 18.5 g; mean brain mass: 0.21 and 0.30 g, respectively) and two large species, Crocidura olivieri and Suncus murinus (body mass: 43.9 and 45.0 g, respectively; brain mass: 0.38 g in both species). They found that the density of proliferated cells in the SVZ was lower in C. olivieri compared to three other species, in the OB the highest level of neurogenesis occurred in N. fodiens, and in the DG the lowest density of newly generated neurons was observed in C. russula. They conclude that the number of newly generated neurons in an adult shrew’s brain is independent of the brain size, and molecular mechanisms of neurogenesis appeared to be different in particular neurogenic structures.
The paper is available at: https://doi.org/10.3390/ijms22147664