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Cognitive
Psychology PSY 504
VU
Lesson
03
COGNITIVE
NEUROPSYCHOLOGY
Cognitive
Neuro-psychology describes cognition at
the hardware level to use
the computer
metaphor.
The neural architecture of
cognition is the basis on
which the edifice of the
software
level
is erected.
At
this level it is possible to
explain many visual and
auditory phenomena. Higher
level cognitions,
however,
remain a mystery.
Neuropsychological
Methods:
Brain-injured
Humans
The
study of brain injured
humans has greatly enriched
our understanding of human
cognition. It
has
allowed psychologists to design
split brain experiments
which made us aware of
the
differences
between the right and
the left hemispheres of the
brain.
Brains
of Dead People
The
study of brains of dead
people has also added to
understanding of cognition but to a
limited
extent.
The brains of people with
certain brain disorders were
studied to see if any traces
of the
illness
can shed light on normal
brain functioning.
Neuro-imaging
X-Rays
have also contributed to our
understanding of brain processes.
But even more
revealing
have
been Magnetic Resonance
Imaging (MRI) and functional
MRI (fMRI) scanning
techniques.
The
MRI technique is quite intrusive
and yields relatively
limited information. The
fMRI, however,
allows
live brain scans and is
also less intrusive and
radiation free. But it still
remains a hardware
level
understanding of the brain
and can never substitute a
software level
description.
Animal
Studies
A
really controversial method of
studying the neural
processes is to study live
animals. This
method
is controversial because these
animals are subjected, for
example, to brain
surgeries
where
parts of the brain are
removed to see how they
would function. The
conditions in which
these
animals are kept have
also come under question. No
doubt, a lot of useful
information has
been
obtained by studying animals
but the ethical controversy
remains.
The
Neuron
There
are 70 billion neurons in
the brain. A neuron is a
specialized cell that
transmits and stores
information
of different kinds. The cell
body contains a nucleus at
its centre which governs
the
functions
of the neuron. There are
tiny branches connected to
the cell body called
dendrites
which
bring information to the
neuron from other neurons.
On the other side neuron
has a branch
called
the axon which transmits
information from the neurons
to the muscles.
The
synapse
The
neuron is not directly
connected to other neurons. A
fluid called the
neurotransmitter moves
between
the dendrites from one
neuron and the axon of
the other neuron. The
gap between the
neuron
which contains the
neurotransmitter is called the
synapse. It is the synapse
which
transmits
the electric impulse
generated in one neuron to
the other neurons.
Organization
of the Brain
The
brain can be divided into
four lobes: Occipital lobe,
frontal lobe, temporal lobe
and parietal
lobe.
In each lobe are performed
certain specialized
functions.
Several
attached pictures describe
different features of the
neuron, synapses, and
brain
organization.
Study these pictures to get
a broad idea of how the
brain structure is
organized.
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