Sculpting a Nervous System

Presented by Claude Cruz
Zoom passcode is presentation date: 042224

Please NOTE correct date and time on this announcement; earlier announcement was incorrect. We hope to see you on Monday, 4/22.

An advanced mammalian nervous system is perhaps the most intricately-patterned matter known to mankind. Beyond the sheer number of physical elements involved--- over 86 billion neurons, a comparable number of associated glial cells, and perhaps 100 trillion synapses in the human brain--- those elements are connected with one another in intricate and specific ways. How can a system with such exquisite organization come to be?

In this presentation, we’ll explore some of the mechanisms that play a role in creating a nervous system. As we’ll see, both nature (through genetic “programming”) and nurture (through the constant stream of interactions between an organism and its surrounding environment) play central roles. The interplay between these forces varies over time, resulting in a sequence of developmental time-windows, as well as in waves of waves of proliferation of neural elements, followed by “pruning” of elements.

I was led to explore this “dance” of neural sculpting by my work on simulation of large artificial neural networks. What I’ve learned has led me to modify what started as a fairly static and fixed simulation framework, into one that includes processes analogous to those described above. The resulting framework is quite unlike the processing that underlies the contemporary forms of artificial neural networks of which I’m aware.

*Please check the Brain and Cognitive Science Seminars meetup for updates on link, and to register for future events: https://www.meetup.com/brain-and-cognitive-science-seminar/events/300150551/*

Recommended Reading:
Primary references
· Darnell, D., & Gilbert, S. F. (2017). Neuroembryology. Wiley Interdisciplinary Reviews: Developmental Biology, 6(1), e215.
· Fishell, G., & Kriegstein, A. (2005). Cortical development: new concepts. Neuron, 46(3), 361-362.
· Campbell, K. (2005). Cortical neuron specification: it has its time and place. Neuron, 46(3), 373-376.
· Akula, S. K., Exposito-Alonso, D., & Walsh, C. A. (2023). Shaping the brain: The emergence of cortical structure and folding. Developmental cell, 58(24), 2836-2849.
· Polleux, F. (2005). Genetic Mechanisms Specifying Cortical Connectivity: Let’s Make Some Projections Together. Neuron, 46(3), 395-400.
· Flames, N., & Marín, O. (2005). Developmental mechanisms underlying the generation of cortical interneuron diversity. Neuron, 46(3), 377-381.
Supplementary references
· Parnavelas, J. G. (2002). The origin of cortical neurons. Brazilian Journal of Medical and Biological Research, 35, 1423-1429.
· Galakhova, A. A., Hunt, S., Wilbers, R., Heyer, D. B., de Kock, C. P. J., Mansvelder, H. D., & Goriounova, N. A. (2022). Evolution of cortical neurons supporting human cognition. Trends in cognitive sciences, 26(11), 909-922.
· Zang, Y., Chaudhari, K., & Bashaw, G. J. (2021). New insights into the molecular mechanisms of axon guidance receptor regulation and signaling. Current topics in developmental biology, 142, 147-196.
· Hensch, T. K., & Bilimoria, P. M. (2012, July). Re-opening windows: manipulating critical periods for brain development. In Cerebrum: the Dana forum on brain science (Vol. 2012). Dana Foundation.
· Hollville, E., Romero, S. E., & Deshmukh, M. (2019). Apoptotic cell death regulation in neurons. The FEBS journal, 286(17), 3276-3298.
· Edelman, G. M., & Gally, J. A. (2001). Degeneracy and complexity in biological systems. Proceedings of the National Academy of Sciences, 98(24), 13763-13768.
· Edelman, G. M. (1992). Bright air, brilliant fire. New York, NY, USA:: BasicBooks.