Levels of the nervous system

Table 1: Levels of the nervous system. Based on [Shepherd, 1994, figure 1.1].

A	Behavior	Psychological descriptions, ...
B	Distributed systems	Brain mapping on a macroscopic level as obtainable with PET, SPECT, fMRI, EEG
C	Local Circuits	Cortex layers, ...
D	Neuron
E	Microcircuit	The pattern of synaptic connections
F	Synapse
G	Macromolecules	Membranes, molecules, ions
H	Genes

Table 1 shows a way to subdivide neuroscience that focuses on the scale: Macroscopic neuroscience focuses on a system level description with, e.g., brain areas. Microscopic neuroscience focus on, e.g., molecular biology.