Branches of the Mind: A History of Neurogenesis and Synapse Formation

The history of neurogenesis and synaptogenesis research signifies the profound shift in our knowledge of the brain. From the well-established belief that neural growth stopped after early development to the ground-breaking discoveries that proved the brain remains dynamic and capable of renewal throughout adult life.

Neurogenesis and Synaptogenesis - What’s the difference? 

Neurogenesis is the process of generating new neurons [1]. According to ‌Estrin et al. (2020), synaptogenesis refers to the formation of synapses, the points of contact where information is transmitted between neurons [2]. Both processes contribute to brain plasticity. Both neurogenesis and synaptogenesis occur in adulthood, but neurogenesis is more focused in specific brain regions like the hippocampus and olfactory bulb, and most active during embryonic development. While synaptogenesis occurs throughout the brain and is related to ongoing learning and adaptation [3]. 

Which leaf of insight surprised you the most? Share your thoughts in the comments below.

References

[1] Jahanshahi, A., Temel, Y., Lim, L.W., Hoogland, G. and Steinbusch, H.W.M. (2011). Close communication between the subependymal serotonergic plexus and the neurogenic subventricular zone. Journal of Chemical Neuroanatomy, 42(4), pp.297–303. doi:https://doi.org/10.1016/j.jchemneu.2011.09.001. 

[2] ‌Estrin, G.L. and Bhavnani, S. (2020). Synaptogenesis - an overview | ScienceDirect Topics. [online] www.sciencedirect.com. Available at: https://www.sciencedirect.com/topics/biochemistry-genetics-and-molecular-biology/synaptogenesis. 

[3] Lepousez, G., Nissant, A. and Lledo, P.-M. (2015). Adult , Neurogenesis and the Future of the Rejuvenating Brain Circuits. Neuron, 86(2), pp.387–401. doi:https://doi.org/10.1016/j.neuron.2015.01.002. 

Infographic References/Further Reading

[1] Colucci-D’Amato, L., Bonavita, V., & di Porzio, U. (2006). The end of the central dogma of neurobiology: stem cells and neurogenesis in adult CNS. Neurological Sciences, 27(4), 266–270. https://doi.org/10.1007/s10072-006-0682-z

[2] Cull-Candy, S. and Jenkinson, D. (2003). Bernard Katz 1911–2003. Nature Neuroscience, 6(7), pp.659–660. doi:https://doi.org/10.1038/nn0703-659.

[3] Altman, J. (1962). Are New Neurons Formed in the Brains of Adult Mammals? Science, 135(3509), pp.1127–1128. doi:https://doi.org/10.1126/science.135.3509.1127.

[4] Discovering Synaptic Pruning. (2023). Cambridge University Press eBooks, [online] pp.5–12. doi:https://doi.org/10.1017/9781009267038.003. 

[5] Goldman, S.A. and Nottebohm, F. (1983). Neuronal production, migration, and differentiation in a vocal control nucleus of the adult female canary brain. Proceedings of the National Academy of Sciences of the United States of America, [online] 80(8), pp.2390–2394. doi:https://doi.org/10.1073/pnas.80.8.2390. 

[6] Seki, T. and Arai, Y. (1993). Highly polysialylated neural cell adhesion molecule (NCAM-H) is expressed by newly generated granule cells in the dentate gyrus of the adult rat. The Journal of Neuroscience, 13(6), pp.2351–2358. doi:https://doi.org/10.1523/jneurosci.13-06-02351.1993. 

[7] Kuhn, H., Dickinson-Anson, H. and Gage, F. (1996). Neurogenesis in the dentate gyrus of the adult rat: age-related decrease of neuronal progenitor proliferation. The Journal of Neuroscience, 16(6), pp.2027–2033. doi:https://doi.org/10.1523/jneurosci.16-06-02027.1996. 

[8] Eriksson, P.S., Perfilieva, E., Björk-Eriksson, T., Alborn, A.-M., Nordborg, C., Peterson, D.A. and Gage, F.H. (1998). Neurogenesis in the adult human hippocampus. Nature Medicine, [online] 4(11), pp.1313–1317. doi:https://doi.org/10.1038/3305.

[9] Gideon, S., Oke, OO,. Ekokojde, JW., Gbayisomore, T.J., Anene-Ogbe, M.C., Glory, F., et al. (2024) Adult Neurogenesis: A Review of Current Perspectives and Implications for Neuroscience Research. Journal of Neuroscience and Neurological Disorders 8(2): 106-114. 

[10] Duque, A., Arellano, J.I. and Rakic, P. (2022). An assessment of the existence of adult neurogenesis in humans and value of its rodent models for neuropsychiatric diseases. Molecular Psychiatry, [online] 27(1), pp.377–382. doi:https://doi.org/10.1038/s41380-021-01314-8. 

[11] Marzola, P., Melzer, T., Pavesi, E., Gil-Mohapel, J. and Brocardo, P.S. (2023). Exploring the role of neuroplasticity in development, aging, and neurodegeneration. Brain Sciences, [online] 13(12), pp.1–32. doi:https://doi.org/10.3390/brainsci13121610.