1. DEVLOPMENT OF BRAIN AND IT'S
CONGENITAL ANOMALIES
NEUROSCIENCE
GUIDED BY :- DR.S.D.TRIPATHI.SIR
SUBMITTED BY:-MR.SAURABH ASHOKRAO JADHAV
2. INTRODUCTION
• Neural development refers to the processes that generate,
shape, and reshape the NERVOUS SYSTEM of animals,
from the earliest stages of Embryogenesis to Adulthood.
• It is NeuroEctodermal in Origin
• Brain is develop from anterior end of neural tube
5. Left lateral views and sections through the developing brain.
A, The three primary brain vesicles. B, Development of telencephalon and diencephalon.
C, Development of the metencephalon and myelencephalon
6.
7. A-Midline longitudinal section through the fore-brain showing the medial wall of the right cerebral
hemisphere and the right thalamus and hypothalamus
B-Cross-section through the fore-brain at the level indicated, Xshowing the lateral ventricles, the
hippocampal lobes, the third ventricle and the choroid plexus
DEVELOPMENT OF PROSENCEPHALON
8. A- Midline longitudinal section through the fore-brain at a later stage
B- Cross-section through the fore-brain at the level indicated, X.
C- Cross-section through the fore-brain at the level indicated, Y.
9. A-Midline longitudinal section through the fore-brain in the early foetal period showing the
relationships of the
developing brain structures.
B-Cross-section at the level indicated, X.
11. Development of the basal and alar plates in the mesencephalon. Section through the mesencephalon at an early
stage of development, A, and at a later stage of development, B, showing the alar and basal plates, the wide neural
canal and migration of cells from the alar plates (arrows). C, Section through the mesencephalon showing the
reduced size of the mesencephalic aqueduct and the development of motor and sensory nuclei from the basal and
alar plates. The crura cerebri are also shown. Sections are at the levels indicated.
12. DEVELOPMENT OF RHOMBENCEPHALON
A-Dorsal views and cross-sections at the levels indicated through the myelencephalon and
B- the developing cerebellum and pons
13. Dorsal view and longitudinal section of the developing cerebellum showing the commencement of
surface folding
14. Left lateral view and longitudinal section of the developing cerebellum showing marked folding of the
surface, the formation of folia.
15.
16. A CONGENITAL MALFORMATION IN CALVES; THERE IS A SMALL OPENING ON THE
SURFACE OF THE CALVARIA; THE HOLE CONNECTS WITH A DEFORMED DIENCEPHALON
WHICH MAY DISCHARGE CEREBROSPINAL FLUID
CONGENITAL ANOMALIES OF BRAIN
17. HYDROCEPHALUS,
an increase in volume of the CSF, can appear similar to hydranencephaly, but in hydrocephalus the ventricles retain a complete
ependymal lining. Clinical signs can vary from mild to severe and include seizures, lethargy, or other forebrain
abnormalities. There may be extensive expansion of the lateral ventricles in the frontal lobes. Hydrocephalus is seen sporadically
in all large animals, although it is relatively common in calves, in which inheritance and vitamin A deficiency have been
implicated.
Holoprosencephaly
is a disorder caused by the failure of the prosencephalon (the
embryonic forebrain) to sufficiently divide into the double lobes of
the cerebral hemispheres. ... Lobar, in which there is considerable
evidence of separate brain hemispheres, is the least severe form.
18. Cerebellar hypoplasia is most frequently found in kittens and
calves. The most common cause is prenatal or perinatal viral
infections.
CEREBELLAR HYPOPLASIA
Cerebellar hypoplasia (fig. describes a situation
where an insufficiency of neurons causes
hypoplasia of the granular layer of the cerebellum.
In severe cases, the Purkinje neurons will also be
destroyed. The condition is most frequently found
in kittens and calves, most commonly caused by
prenatal or perinatal viral infections. The specific
viruses are the feline panleukopaenia virus and the
bovine virus diarrhoea (BVD) virus.
CEREBELLAR ABIOTROPHY
Cerebellar abiotrophy is characterized by the
degeneration
of the Purkinje cells in the already formed
cerebellar cortex. It occurs postnatally or, occasionally,
prenatally and has been observed in many
domestic species. The primary defect that causes the
degeneration is not known.
19. ARNOLD-CHIARI MALFORMATION
Arnold-Chiari malformation is a condition
characterized
by caudal displacement and herniation
of
cerebellar structures through the
foramen magnum
into the cranial cervical vertebral canal.
Arnold-
Chiari malformation is often accompanied
by spina
bifida, meningomyelocoele, and
hydrocephalus.
20. EXENCEPHALY
Failure in the closure of the rostral neuropore,
resulting in abnormal fore-brain development and
interference with fusion of the bones of the cranium,
gives rise to the condition referred to as
exencephaly.When the cranial defect is small, the
meninges can herniate and the
anomaly is referred to as cranial meningocoele. A large
cranial defect, which allows the meninges and part of
the brain to herniate, is referred to as encephalocoele.
MICROCEPHALY
Microcephaly, an abnormally small brain, has
been reported in calves, lambs, and piglets. Since the
size of the cranium depends on the development of
the brain, the cranial vault is considerably smaller
than normal. External features of microcephaly
include a narrow and flattened frontal area of the
cranium. Cranial bones appear thicker than normal.
The cause of the condition may be genetic or a
prenatal insult such as an infection or exposure to
a teratogen.
21. HYDRANENCEPHALY
In hydranencephaly, the cerebral hemispheres
are replaced by two fluid-filled sacs. The brain
stem is usually not affected, but some degree of
cerebellar hypoplasia may be observed. In domestic
animals this condition is most commonly caused by
an in utero viral infection (blue tongue virus in
ruminants and panleukopaenia in cats) or, more
rarely, by an interruption of the blood supply to the
telencephalon.
23. MENINGOCELE AND LIPOMENINGOCELE
Meningocele typically causes mild problems
with a sac of fluid present at the gap in the
spine. Myelomeningocele, also known as
open spina bifida, is the most severe form.
Associated problems include poor ability to
walk, problems with bladder or bowel control,
hydrocephalus, a tethered spinal cord, and
latex allergy.
