Dear all, here are two papers dealing with the dolphin brain as a model for investigating the occurrence of "adult neurogenesis" in mammals devoid of olfaction. Adult neurogenesis, namely the continuous genesis of new neurons through adulthood, in laboratory rodents is linked to specific functions such as olfaction and, for this reason, is highly reduced in humans. The first paper shows that neurogenic processes are completely absent in dolphins (since birth); the second one is a review article discussing the high reduction of adult neurogenesis in humans and the evolutionary aspects of such reduction. The occurrence/absence of neurogenesis in humans is at present a very hot topic in Neurosciences and the study of the dolphin brain greatly contributes to the general debate. Parolisi R, Cozzi B, Bonfanti L (2018) *Humans and Dolphins: Decline and Fall of Adult Neurogenesis*. Front. Neurosci., 12: 497 doi.org/10.3389/fnins.2018.00497 <https://doi.org/10.3389/fnins.2018.00497> Frontiers link: https://www.frontiersin.org/articles/10.3389/fnins.2018.00497/full *Abstract *Pre-clinical research is carried out on animal models, mostly laboratory rodents, with the ultimate aim of translating the acquired knowledge to humans. In the last decades, adult neurogenesis (AN) has been intensively studied since it is viewed as a tool for fostering brain plasticity, possibly repair. Yet, occurrence, location, and rate of AN vary among mammals: the capability for constitutive neuronal production is substantially reduced when comparing small-brained, short living (laboratory rodents) and large-brained, long-living species (humans, dolphins). Several difficulties concerning scarce availability of fresh tissues, technical limits and ethical concerns did contribute in delaying and diverting the achievement of the picture of neurogenic plasticity in large-brained mammals. Some reports appeared in the last few years, starting to shed more light on this issue. Despite technical limits, data from recent studies mostly converge to indicate that neurogenesis is vestigial, or possibly absent, in regions of the adult human brain where in rodents neuronal addition continues into adult life. Analyses carried out in dolphins, mammals devoid of olfaction, but descendant of ancestors provided with olfaction, has shown disappearance of neurogenesis in both neonatal and adult individuals. Heterogeneity in mammalian structural plasticity remains largely underestimated by scientists focusing their research in rodents. Comparative studies are the key to understand the function of AN and the possible translational significance of neuronal replacement in humans. Here, we summarize comparative studies on AN and discuss the evolutionary implications of variations on the recruitment of new neurons in different regions and different species. Keywords: adult neurogenesis, brain plasticity and aging, comparative anatomy, doublecortin, immature neurons Parolisi R, Cozzi B, Bonfanti L (2017) *Non-neurogenic SVZ-like niche in dolphins, mammals devoid of olfaction*. Brain Structure and Function 222:2625-2639. doi: 10.1007/s00429-016-1361-3 Brain Struct Funct link: https://rdcu.be/2Cyu <http://em.rdcu.be/wf/click?upn=lMZy1lernSJ7apc5DgYM8W6vXOy-2FXiCEqhnH6G7bIGA-3D_W2yUJrD0YNSxWycdUQ0eMbHQvY5Q-2BV87wQSV8QlVeUo71-2BGEr06xMoJgkCa7RIPJqnshGELwEvwOc8ZtWYFr4rr0HcTFGd1A8zLAaFYCeP3KNeniDkiIUnpfdixS0HcFVWln5knU28Pg-2B3LAAhIICMTw1jNCaLhdga0Of03MgAQbmSZOxl0NxuU1ZfXu6nLu-2F7gSeWupsFnbxoR8rFW6Oa9-2FCz-2BxQZZi4t9ZOYC50VoWD2xQdI28wUH8afd9Z8RS9JyTdASLEndb8-2BHL3C5Qcw-3D-3D> Abstract Adult neurogenesis has been implicated in brain plasticity and brain repair. In mammals, it is mostly restricted to specific brain regions and specific physiological functions. The function and evolutionary history of mammalian adult neurogenesis has been elusive so far. The largest neurogenic site in mammals (subventricular zone, SVZ) generates neurons destined to populate the olfactory bulb. The SVZ neurogenic activity appears to be related to the dependence of the species on olfaction since it occurs at high rates throughout life in animals strongly dependent on this function for their survival. Indeed, it dramatically decreases in humans, who do not depend so much on it. This study investigates whether the SVZ neurogenic site exists in mammals devoid of olfaction and olfactory brain structures, such as dolphins. Our results demonstate that a small SVZ-like region persists in these aquatic mammals. However, this region seems to have lost its neurogenic capabilities since neonatal stages. In addition, instead of the typical newly generated neuroblasts, some mature neurons were observed in the dolphin SVZ. Since cetaceans evolved from terrestrial ancestors, non-neurogenic SVZ may indicate extinction of adult neurogenesis in the absence of olfactory function, with the retention of an SVZ-like anatomical region either vestigial or of still unknown role. Keywords: Adult neurogenesis; Brain plasticity; Cetaceans; Doublecortin; Evolution; Olfactory bulb; Subventricular zone Luca Bonfanti & Bruno Cozzi Luca BONFANTI Dpt. of Veterinary Sciences, University of Turin Neuroscience Institute Cavalieri Ottolenghi (NICO) _http://www.nico.ottolenghi.unito.it_ Tel: (0039) 011 6706606 Bruno Cozzi Dept. of Comparative Biomedicine and Food Science University of Padova viale dell'Università 16 35020 Legnaro (PD) - ITALY mail bruno.cozzi@unipd.it fax +39.049.8272796 phone +39.049.8272626