Enriched Odor Exposure Increases the Number of Newborn Neurons in the Adult Olfactory Bulb and Improves Odor Memory

By Christelle Rochefort, G. Gheusi, J. Vincent, Pierre Marie Lledo. Journal of Neuroscience, 2002

702 citations recorded by the source corpus.

In the mammalian forebrain, most neurons originate from proliferating cells in the ventricular zone lining the lateral ventricles, including a discrete area of the subventricular zone (SVZ). In this region, neurogenesis continues into adulthood. Most of the cells generated in the SVZ are neuronal precursors with progeny that migrate rostrally along a pathway known as the rostral migratory stream before they reach the main olfactory bulb (MOB) where they differentiate into local interneurons. The olfactory system thus provides an attractive model to investigate neuronal production and survival, processes involving interplay between genetic and epigenetic influences. The present study was conducted to investigate whether exposure to an odor-enriched environment affects neurogenesis and learning in adult mice. Animals housed in either a standard or an odor-enriched environment for 40 d were injected intraperitoneally with bromodeoxyuridine (BrdU) to detect proliferation among progenitor cells and to follow their survival in the MOB. The number of BrdU-labeled neurons was not altered 4 hr after a single BrdU injection. In contrast, the number of surviving progenitors 3 weeks after BrdU injection was markedly increased in animals housed in an enriched environment. This effect was specific because enriched odor exposure did not influence hippocampal neurogenesis. Finally, we showed that adult mice housed in odor-enriched cages display improved olfactory memory without a change in spatial learning performance. By maintaining a constitutive turnover of granule cells subjected to modulation by environmental cues, ongoing bulbar neurogenesis could be associated with improved olfactory memory.

Subfields: Developmental Neuroscience, Neurology, Sensory Systems

View Paper: https://www.semanticscholar.org/paper/6f102bcf72951231c01817399b918b7c822842a4

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Citations in the corpus

Pattern separation: a common function for new neurons in hippocampus and olfactory bulb (2011, unknown): “In fact, prolonged enrichment of the odor environment enhances the survival (Rochefort et al., 2002) of adult-”
Adult Neurogenesis in Humans. (2015, background): “In mice, odor stimuli result in higher survival rates of newborn neurons (Rochefort et al. 2002), and a deprivation of olfactory stimuli in young mice leads to apoptosis in the olfactory glomeruli accompanied by smaller bulbs (Cummings et al.”
Fragile X Mental Retardation Protein Regulates New Neuron Differentiation in the Adult Olfactory Bulb (2011, methodology): “To further challenge the functional integration of mutated neurons in a wild-type network, we exposed shRNA-injected animals to an enriched olfactory environment consisting of a new odor every day (Rochefort et al., 2002), thus exposing mutated neurons to a more active network during their integrati”
Adult neurogenesis and the olfactory system. (2009, background): “Olfactory enrichment increases neuronal survival and improves odor memory (Rochefort et al., 2002).”
Non-topographical contrast enhancement in the olfactory bulb (2006, background): “The mitral-granule network is therefore potentially well suited to transform glomerular output in accordance with odor learning, presumably through the learned modification of mitral-granule reciprocal synapses and learning-correlated granule cell neurogenesis [96-99], and perhaps involving the gene”
Dopamine depletion impairs precursor cell proliferation in Parkinson disease (2004, background): “Evidence from experimental animals suggests that olfactory neurogenesis is implicated in the memorization of odor”
Learning and Survival of Newly Generated Neurons: When Time Matters (2008, background): “In contrast, long-term exposure to a rich range of odors increases the survival of newly generated interneurons (Rochefort et al., 2002) and transiently improves odor memory (Rochefort and Lledo, 2005), suggesting a potential role for adult neurogenesis in olfactory memory.”
Functional Maturation of the First Synapse in Olfaction: Development and Adult Neurogenesis (2008, background): “In addition, they could provide a functional basis for the activity-dependent life-or-death decisions made by newborn PGCs integrating into the mature glomerular network (Rochefort et al., 2002; Alonso et al., 2006; Mandairon et al., 2006).”
Becoming a new neuron in the adult olfactory bulb (2003, background): “Similarly, increasing the number of newborn interneurons in the OB improves olfactory memor”
New neurons in the dentate gyrus are involved in the expression of enhanced long‐term memory following environmental enrichment (2005, background): “It is likely, however, that MAM also reduced neurogenesis in the subventricular zone, with a consequential reduction in the number of newborn cells migrating to the olfactory bulb (Luskin, 1993; Rochefort et al., 2002).”
Interneurons Produced in Adulthood Are Required for the Normal Functioning of the Olfactory Bulb Network and for the Execution of Selected Olfactory Behaviors (2009, methodology): “Indeed, a clear correlation was established when mice exposed to an enriched environment displayed both an increased neurogenesis and short-term olfactory memory (Rochefort et al., 2002).”
Neurogenesis Drives Stimulus Decorrelation in a Model of the Olfactory Bulb (2012, background): “It is known that larger fractions of granule cells survive if the animal is kept in odorenriched enviroments [19] or if the excitability of the granule cells is genetically enhanced [41].”
A hypothesis about the role of adult neurogenesis in hippocampal function. (2004, background): “Increasing evidence suggests that neurogenesis may play a key role in olfactory processing in the adult brain (6, 11, 33, 40).”