The document describes commissural fibers which interconnect similar cortical areas across the two cerebral hemispheres, organized into several major commissures: the corpus callosum, anterior commissure, posterior commissure, hippocampal commissure, and habenular commissure. The corpus callosum is the largest commissure, consisting of about 100 million fibers connecting the cerebral cortex lobes. Each commissure has specific functions and connections, with the anterior and posterior commissures connecting various regions of the temporal lobes, olfactory areas, and structures related to the hippocampal formation.

1. COMMISURAL FIBRES
CHAITRA CHINMAYEE M K

2. COMMISURAL FIBRES
The commissural fibres interconnect the identical
cortical areas of the two cerebral hemispheres
(interhemispheric fibres). The bundles of such fibres
are termed commissures.
The important commissures of the brain are as
follows:
1. Corpus callosum.
2. Anterior commissure.
3. Posterior commissure.
4. Hippocampal commissure.
5. Habenular commissure.

3. CORPUS CALLOSUM
The corpus callosum is the largest commissure
of the brain. It consists of about 100 million
fibres. It interconnects two lobes of the
cerebral cortex.

4. ANTERIOR COMMISSURE
The anterior commissure is a small round bundle of white
fibres which crosses the midline in the upper part of the
lamina terminalis, immediately in front of the anterior
column of the fornix and interventricular foramen.
Posterior Neocortical
Component
Anterior Paleocortical
Component
It is large, interconnects
the lower and anterior
parts of the temporal
lobes
It is smaller, interconnects
the olfactory regions of
the two hemispheres
It has two components

5. POSTERIOR COMMISSURE
The posterior commissure is a slender bundle of
white fibres which crosses the midline through
the inferior lamina of the stalk of pineal gland.

6. HIPPOCAMPAL COMMISSURE
It is also called the commissure of fornix,
which interconnects the crura of fornix of
the two sides and thus forms the
hippocampal formation.

7. HABENULAR COMMISSURE
The habenular commissure is a slender bundle of
white fibres which crosses the midline through the
superior lamina of the stalk of pineal gland.