Редактирование: Whole brain emulation (раздел)

=== Neurogenesis ===

* Recent results show that neurogenesis persists in some brain regions in adulthood, and might 
have nontrivial functional consequences (Saxe, Malleret et al., 2007). During neurite 
outgrowth, and possibly afterwards, cell adhesion proteins can affect gene expression and 
possible neuron function by affecting second messenger systems and calcium levels (Crossin 
and Krushel, 2000). However, neurogenesis is mainly confined to discrete regions of the brain 
and does not occur to a great extent in adult neocortex (Bhardwaj, Curtis et al., 2006). 

* Since neurogenesis occurs on fairly slow timescales (> 1 week) compared to brain activity and 
normal plasticity, it could probably be ignored in brain emulation if the goal is an emulation 
that is intended to function faithfully for only a few days and not to exhibit truly long‐term 
memory consolidation or adaptation. 

* A related issue is remodelling of dendrites and synapses. Over the span of months dendrites 
can grow, retract and add new branch tips in a cell type‐specific manner (Lee, Huang et al., 
2006). Similarly synaptic spines in the adult brain can change within hours to days, although 
the majority remain stable over multi‐month timespans (Grutzendler, Kasthuri et al., 2002; 
Holtmaat, Trachtenberg et al., 2005; Zuo, Lin et al., 2005). Even if neurogenesis is ignored and 
the emulation is of an adult brain, it is likely that such remodelling is important to learning 
and adaptation.

*  Simulating stem cell proliferation would require data structures representing different cells 
and their differentiation status, data on what triggers neurogenesis, and models allowing for 
the gradual integration of the cells into the network. Such a simulation would involve 
modelling the geometry and mechanics of cells, possibly even tissue differentiation. Dendritic 
and synaptic remodelling would also require a geometry and mechanics model. While 
technically involved and requiring at least a geometry model for each dendritic compartment 
the computational demands appear small compared to neural activity.