Редактирование: Whole brain emulation (раздел)

==== Cell Type Identification ====

Distinguishing neurons from glia and identifying their functional type requires other 
advances in image recognition. 
 
The definition of neuron types is debated, as well as the number of types. There might be as 
many as 10,000 types, generated through an interplay of genetic, posttranscriptional, 
epigenetic, and environmental interactions (Muotri and Gage, 2006). There are some 30+ 
named neuron types, mostly categorized based on chemistry and morphology (e.g. shape, the 
presence of synaptic spines, whether they target somata or distal dendrites). Distinguishing 
morphologically different groups appear feasible using geometrical analysis (Jelinek and 
Fernandez, 1998). 
 
In terms of electrophysiology, excitatory neurons are typically classified into regular‐spiking, 
intrinsic bursting, and chattering, while interneurons are classified into fast‐spiking, burst 
spiking, late‐spiking and regular spiking. However, alternate classifications exist. (Gupta, 
Wang et al., 2000) examined neocortical inhibitory neurons and found three different kinds of 
GABAergic synapses, three main electrophysiological classes divided into eight subclasses, 
and five anatomical classes, producing 15+ observed combinations. Examining the subgroup 
of somatostatin‐expressing inhibitory neurons produced three distinct groups in terms of 
layer location and electrophysiology (Ma, Hu et al., 2006) with apparently different functions. 

* The morphology and electrophysiology of inhibitory neurons in the 2nd and 3rd layers of trhe prefrontal cortex also indicates the existence of different clustered types.
 
Overall, it appears that there exist distinct classes of neurons in terms of neurotransmitter, 
neuropeptide expression, protein expression (e.g. calcium binding proteins), and overall 
electrophysiological behaviour. Morphology often shows clustering, but there may exist 
intermediate forms. Similarly, details of electrophysiology may show overlap between 
classes, but have different population means.  
 
Some functional neuron types are readily distinguished from morphology (such as the five 
types of the cerebellar cortex). A key problem is that while differing morphologies likely 
implies differing functional properties, the reverse may not be true. Some classes of neurons 
appear to show a strong link between electrophysiology and morphology (Krimer, Zaitsev et 
al., 2005) that would enable inference of at least functional type just from geometry. In the 
case of layer 5 pyramidal cells, some studies have found a link between morphology and 
firing pattern (Kasper, Larkman et al., 1994; Mason and Larkman, 1990), while others have 
not (Chang and Luebke, 2007). It is quite possible that different classes are differently 
identifiable, and that the morphology‐function link could vary between species.  

* Unique and identifiable neurons are relative common in small animals become less and less common as brain size increases
* Identifiable neurons are present in small animals
**They can be distuinguished from other neurons inside the individual or across individuals(Bullock, 2000)
**