Basic brain region properties

siibra makes no distinction between brain regions and region trees: Each Region object represents a subtree with a (possibly empty) set of child regions, and has a pointer to its parent region in the hierarchy. As mentioned before, Parcellation objects are also special regions, with no parent and additional functionalities. Consequently, the parcellation of a region can be accessed as the region’s “root” attribute (but “parcellation” is also provided as a shortcut property to this)

Start by importing the package.

import siibra

Let’s fetch the region from the Julich-Brain parcellation representing the primary visual cortex.

v1 = siibra.get_region('julich 2.9', 'v1')

The corresponding parcellation is just the root region:

print(v1.root)
print(v1.parcellation)

Julich-Brain Cytoarchitectonic Atlas (v2.9)
Julich-Brain Cytoarchitectonic Atlas (v2.9)

The primary visual cortex is part of the occipital cortex:

v1.parent

<Region(identifier='minds/core/parcellationatlas/v1.0.0/94c1125b-b87e-45e4-901c-00daee7f2579-290_OCCIPITAL_CORTEX', name='occipital cortex', species='Homo sapiens')>

It represents a subtree, with its children being the respective areas on each hemisphere:

# show the tree representation
v1.render_tree()

# return the actual list of child region objects
v1.children

# we can access children with fuzzy string matching using "find"
# as well as by their index
v1l = v1.find("left")
print(v1l)

Area hOc1 (V1, 17, CalcS)
├── Area hOc1 (V1, 17, CalcS) left
╰── Area hOc1 (V1, 17, CalcS) right
[<Region(identifier='minds/core/parcellationatlas/v1.0.0/94c1125b-b87e-45e4-901c-00daee7f2579-290_AREA_HOC1_V1_17_CALCS_LEFT', name='Area hOc1 (V1, 17, CalcS) left', species='Homo sapiens')>]