Task 3 Development and plasticity
1. PART 1: 1) How does the brain develop from foetus to adult? 2) What is normal plasticity in children
and adults?
2. PART 2: 1) Can the brain recover from damage? 2) Is there a difference between children and adults in
recovery rate? 3) Which factors influence recovery?
3. PART 3: 1) What are phantom limb pain and sensations, are they very common? 2) How can these
sensations and pain be explained? 3) How can you treat phantom limb sensations and pain?
PART 1: brain development and plasticity_________________________________________________
Kolb, B. & Whishaw, I.Q. (2015). Fundamentals of Human Neuropsychology (7th Edition) H3
3.3: Origin and development of the central nervous system
The developing brain, originates as a three- part structure (A). These 3 divisions surround a canal
field with CSF. At later stages in development, the front and back components expand greatly and
subdivide further, into five regions (B). These are grouped according to the three- part scheme of
forebrain, brainstem and spinal cord (C).
Figure 3.10 A: the 3 regions in de primitive developing brain can be seen as enlargements at
the end of the embryonic spinal cord.
o The prosencephalon (front brain) is responsible for olfaction
o the mesencephalon (middle brain) for vision and hearing
o the rhombencephalon (hindbrain)controls movement and balance. The spinal cord is
considered part of the hindbrain.
Figure 3.10 B:
o The anterior prosencephalon develops further to form the cerebral hemispheres
(cortex and related structures), known as the telencephalon (end brain). The
posterior prosencephalon, becomes the diencephalon (between brain) and includes
the thalamus.
o The mesencephalon remains mesencephalon.
o The rhombencephalon develops further, subdividing into the metencephalon (across
brain), which includes the enlarged cerebellum and into the myelencephalon (spinal
brain), the lower region of the brainstem.
Figure 3.10 C: in the complex mammalian brain, the structures are grouped according to the
three- part scheme of forebrain, brainstem and spinal cord. These subdivisions constitute e
the brain’s levels of function.
o The forebrain is considered the locus of cognitive processes, the brainstem of
regulatory functions (drinking, eating, sleeping, etc.), and the spinal cord of more
reflexive motor functions.
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,The brain begins as a tube, and remains
‘hollow’ and filled with CSF during and after
development. There are four ventrciles. The
cerebral aqueduct connects the third and
fourth ventricles. CSF is produced by
ependymal glial cells, located adjacent to
the ventricles. CSF flows from the lateral
centricles out through the fourth ventricle to
drain into the circulatory system at the base
of the brainstem.
2 lateral ventricles: C shaped lakes underlying the cerebral cortex, one in each hemisphere.
The third and fourth ventricle connected by the cerebral aqueduct in the brainstem.
Kolb, B. & Whishaw, I.Q. (2015). Fundamentals of Human Neuropsychology (7th Edition) H23
23.1: Approaches to studying brain development
Behavioural changes resulting from neural function can be examined in 3 ways:
Look at the nervous system maturation and correlate it with the development of specific
behaviours. As brain structures develop, their functions emerge and are manifested in
behaviours than we can observe.
o e.g.: link the development of certain brain structures to the development of grasping
or crawling in infants.
Looking at a growing child’s behaviour and then making inferences about neural maturation
(converse of the first).
o E.g.: as language emerges in the young child, we expect to find corresponding
changes in the neural structures that control language & because we observe new
abilities emerging in the teenage years, we infer that they must be controlled by late-
maturing neural structures.
Identify and study factors that influence both brain and behavioural development. In this
perspective, the mere emergence of a certain brain structure is not enough: we must also
know the experiences that shape how the structure functions and that therefore lead to
certain kinds of behaviours being produced. Some experiences that influence brain function
are related to the effects of hormones, injuries and abnormal genes if behaviour is
influenced by one of these experiences, than structures in the brain that are changed by that
experience are responsible for the behavioural outcome.
o e.g.: we might study how an abnormal secretion of a hormone affects both a certain
brain structure and a certain behavior. We can then infer that because the observed
behavioral abnormality results from the abnormal functioning of the brain structure,
that structure must typically play some role in controlling the behavior.
23.2: development of the human brain:
When an egg is fertilized by a sperm, a human embryo consists of just one single cell. At the
fourteenth day, the embryo consists of several sheets of cells with a raised area in the middle (looks
like fried egg), the primitive body. 3 weeks after conception, this primitive body possesses a
primitive brain (a sheet of cells at one end of the embryo). This sheet of cells rolls up to form a
structure called the neural tube.
The body and the nervous system change rapidly in the next 3 weeks of development. By 7 weeks (49
days), the embryo begins to resemble a miniature person, and by about 100 days after conception,
the brain looks distinctly human; however, it does not begin to form gyri and sulci until about
2
, 7 months. By the end of the ninth month, the
brain has the gross appearance of the adult
human organ, even though its cellular structure
is different.
One single cell several sheets of cells:
the primitive body with primitive brain
primitive brain forms neural tube
mini person (49 days) brain looks
human (100 days) forming gyri and
sulci (7 months) brain has normal
appearance (9 months)
Brain develops from inside to the
outside.
Several changes in the development of the child’s brain take
place in a fixed sequence, as summarized in table 23.1. This
development has 2 extraordinary features:
Nervous-system subcomponents form from cells whose
destination and function are largely predetermined before they
migrate from the ventricular wall where they originate.
Second, development is marked by an initial abundance
of cells, branches, and connections, with an important part of
subsequent maturation consisting of apoptosis, cell death that is
genetically programmed, or pruning back of the initial surfeit.
Deficits in the genetic
program, intrauterine
trauma, the influence of
toxic agents, or other
factors may lead to
peculiarities or errors in
development that
contribute to obvious and
severe deformities. Less
pronounced deficits may
lead to such problems as
learning disabilities or may
appear only as subtle
changes in behavior.
Neuron generation
The neural tube is the brain’s nursery (kinderkamer).
Neural stem cells have the capacity of self- renewal:
when a stem cell divides, it produces two stem cells: one
dies and the other lives and divides again. This process
keeps repeating. In an adult, neural stem cells line the
ventricles, forming the subventricle zone. Stem cells also
give rise to progenitor (precursor) cells. These progenitor
cells also divide, but they eventually produce nondividing
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