basic structure of the vertebrate brain
As can be seen in the excellent
work "Comparative and Functional Anatomy of Vertebrates" by
Hildebrand/Goslow  from page 361 onwards, the brain develops from
the front section of the neural tube. This tube forms
three primary vesicles by constriction, which are
- Forebrain (Prosencephalon)
- midbrain (mesencephalon) and
can be designated. In the
following stage, additional constrictions divide the brain into five
vesicles. This divides the forebrain (prosencephalon) into the final
brain (telencephalon) and the diencephalon. The rhombic brain is
divided into the hindbrain (metencephalon) and the extended medulla
(myelencephalon, medulla oblongata). The midbrain remains undivided.
Thus there are five regions in the brain:
- endbrain (telencephalon)
- Interbrain (diencephalon)
- Midbrain (Mesencephalon)
- elongated medulla (myelencephalon, medulla oblongata).
The midbrain, the isthmic
region and the medulla oblongata are also called the brain stem.
Since vertebrates are
bilateria, i.e. have a bilaterally symmetrical body, the brain and
spinal cord are also partly bilaterally symmetrical.
Therefore, many of its substructures are duplicated.
It is only possible to rationally analyse
signal processing in a system as highly complex as the vertebrate
nervous system if at least the most important of its basic structures
are known. Therefore, the most important subsystems of the vertebrate
brain are listed below. If necessary, the reader may deal with the
basic structure of the vertebral column himself. The following
information was taken from the work "Wie einzigartig ist der Mensch"
 by Gerhard Roth, Spektrum Akademischer Verlag, 2011, from page 169
as well as from the work "Vergleichende und funktionelle Anatomie der
Wirbeltiere" by Hildebrand/Goslow, Springer Verlag, from page 362.
Anyone interested in brain research should therefore have this basic
The substructures of the medulla oblongata of
- The medulla oblongata connects
to the spinal cord and is therefore also called the
- It is the origin of all motor
- It is the target area for the
sensory brain nerves III to XII
- Oculomotor nerve (eye muscle
- Trochlear nerve (also eye
nerve (facial nerve)
- Abducens nerve (another eye
- Facial nerve
- Nervus stato-acusticus (balance
and auditory nerve)
glossopharyngeus (lingual nerve)
- Vagus nerve
nerve (accessory nerve)
- It contains primary and
secondary switching and processing points of somatosensory and
viscerosensory (coming from the intestines) information
- It is the starting point for
the motor parts of the fifth to seventh and ninth to twelfth cranial
- It contains networks and
centres for the control of vital functions such as respiration and
circulation as well as for alertness and attention
- It is a convergence zone of
numerous descending nerve tracts from all parts of the brain
- Although the reticular
formation, which is important for cognitive functions, is part of the
rostral medulla oblongata, it continues to the tegmentum of the
- The median zone of the Formatio
reticularis contains the raphe seeds, which produce the
neurotransmitter serotonin. On the one hand they supply almost all
limbic centres with serotonin, on the other hand their descending
fibres project towards the spinal cord.
- The lateral zone of the
reticular format contains the locus caeruleus, whose neurons produce
norepinephrine and project it into many limbic and associative centers
of the brain.
- The medulla oblongata has a
very conservative basic structure, which has been identical in
principle in all vertebrates since the earliest history of evolution.
Nevertheless, there have been individual and sometimes spectacular
variations in specific vertebrate species (see Roth, above work, page
- The medulla oblongata also
contains the olive pit complex, i.e. the nucleus olivaris principalis,
the nucleus olivaris accessorius medialis and the nucleus olivaris
accessorius posterior (secondary olives)
- In the dorsal section of the
medulla oblongata, the tegmentum, lie the cranial nerve nuclei into
which the various cranial nerves enter.
- Ascending and descending
pathways of various substructures run through the medulla oblongata,
such as the pyramidal path from the motor cortex to the spinal cord.
- The medulla oblongata can also
include the pons (the bridge). The pons itself is subdivided into the
foot of the bridge (pars basalis pontis) and the bridge cap (tegmentum
- The descending fibres of the
pyramid tract, which comes from the cortex and goes to the spinal cord,
pass through the foot of the bridge. Also in the foot of the bridge are the bridge
nuclei (Ncll. pontis), which receive input from the cortex and project
it to the cerebellar nuclei.
- The structure of the medulla
oblongata is symmetrical, one half is responsible for each half of the
body, with some projection paths alternating between the two sides.