Transcript PowerPoint Presentation - Sperry’s Split Brain Studies

Objective 2.6:
*Discuss the use of brain imaging
technologies in investigating the
relationship between biological factors
and behavior.
*section B essay question
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Things to consider….
• You need to be able to explain these technologies,
what they are used for, and their relative use at the
biological level.
• You also need to give examples of research that use
these technologies to demonstrate your knowledge
and understanding of each technique.
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Brain Imaging Technology
 Scientists who studied brain properties and functions
many years ago were forced to experiment on animal
brains, to study autopsied brains (post mortem) of
people who had various cognitive and/or motor
impairments, and to compare the behavior of people
with normal and abnormal brains.
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Brain Imaging Technology
• Imaging is becoming an increasingly
important tool in both research and
treatment at the biological level of
analysis.
• A range of imaging technologies now
provide unprecedented sensitivity to
visualization of brain structure and
function from the level of individual
molecules to the whole brain.
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Brain Imaging Technology
• Many imaging methods are
noninvasive and allow physiological
processes to be monitored over time.
Under the assumption of Principles
that define the BLOA, Imaging is
enabling researchers to identify
neural networks involved in cognitive
processes; understand disease
pathways; recognize and diagnose
diseases early, when they are most
effectively treated; and determine
how therapies work.
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Brain Imaging Technology
• Different types of imaging are used to reveal
brain structure (anatomy), physiology
(functions), and biochemical actions of
individual cells and of the molecules that
compose them, and of cells’ functions,
behaviors and interactions.
• Modern Technologies Include:
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Electroencephalogram (EEG)
Magnetic Resonance Imaging (MRI)
Positron Emission Tomography (PET) scan
Functional Magnetic Resonance Imaging (fMRI)
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Electroencephalogram (EEG)
An amplified recording of the electrical waves
sweeping across the brain’s surface, measured by
electrodes placed on the scalp.
AJ Photo/ Photo Researchers, Inc.
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What does an EEG reading tell
you?
The EEG sums the electrical
activity of neurons. If you see an
increase in activity in a particular
EEG band, it means more neurons
are doing the same thing at the
same time, i.e. greater
neurotransmission in that part of
the brain.
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The use of Electroencephalogram
(EEG) at the BLOA
EEG is used extensively to assess neurological
disorders.
Abnormal decreases of brain activity, usually
associated with large slow EEG waves, can occur
with brain damage.
After very extensive brain damage there may be
no electrical activity recorded from the brain.
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The use of Electroencephalogram
(EEG) at the BLOA
The EEG patterns change when external stimuli
(such as sounds or pictures) are presented. These
stimuli cause or evoke a particular pattern of brain
activity, called the evoked potential.
When we measure a lack of activity during a
certain activity, we are able to conclude that lower
levels of neurotransmission are taking place in that
region of the brain.
http://www.cleanvideosearch.com/media/action
/yt/watch?videoId=I3j2VrhqTAA
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Magnetic Resonance
Imaging
• Another brain-imaging technique is magnetic
resonance imaging (MRI).
• This technology produces three-dimensional
images of the brain’s soft tissues by detecting
magnetic activity from nuclear particles in
brain molecules.
• MRI provides greater accuracy in the
diagnosis of brain diseases than the CAT scan.
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Magnetic Resonance
Imaging
•Magnetic Resonance Imaging (MRI) has been in
widespread use since the early 1980s.
•It uses magnetic fields , radio waves and
computerized enhancement to map out brain
structure. MRI scans provide better images of
brain structure than CAT scans.
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Magnetic Resonance
Imaging
•Doctors often recommend magnetic resonance
imaging (MRI) when investigating whether a
person has Alzheimer's disease, mainly to rule
out other possible causes for cognitive
impairment, such as a brain tumor or blood clot.
•But recent research suggests that MRI could
become a key diagnostic tool by revealing
changes in the brain even before Alzheimer's
symptoms appear.
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Magnetic Resonance
Imaging
•Alzheimer's disease affects the brain in many
ways, but one of the most apparent involves an
area called the hippocampus.
•This part of the brain is responsible for memory
and processing emotion; it also plays a role in an
individual's motor skills.
•http://www.cleanvideosearch.com/media/action/yt/w
atch?videoId=gHWjNls5OSo
•
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Magnetic Resonance
Imaging
•In a small 2008 study, Dr. Michael
Raab, using an MRI to evaluate
patients with Alzheimer's disease,
found that the hippocampus in
those already diagnosed was
nearly a third smaller than
average.
•The hippocampus was 19%
smaller in people who had not
been diagnosed but were
experiencing mental impairment.
•
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Magnetic Resonance
Imaging
•In the aforementioned study, which involved 74
subjects, physicians reported being able to
classify those with Alzheimer's disease and those
without symptoms with 84% accuracy based on
measurement of the hippocampus.
•The researchers were accurate 73% of the time
when distinguishing between patients without
symptoms and those with mild cognitive
impairment.
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Magnetic Resonance
Imaging
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Magnetic Resonance
Imaging
•This would suggest that MRI scans, when done
early on in life, can help to predict and diagnose
cognitive disorders such as Alzheimer's and
dementia that directly effect specific parts of
the brain.
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Magnetic Resonance
Imaging
Researcher: Maguire et al
Study of: Short Term Memory
Year: 2000
Aim:
To investigate if there was
structural changes in the
hippocampal regions of taxi
drivers
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Magnetic Resonance
Imaging
Methods:
• Natural Experiment (natural differences between
participants)
• MRI scans were used to scan the structure of their
hippocampal region, which were compared to already
existing MRI scans of healthy males who did not drive
taxis.
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Magnetic Resonance
Imaging
Results:
• Cab drivers' grey matter enlarges and adapts to help
them store a detailed mental map of the city, according
to research.
• The scientists also found part of the hippocampus grew
larger as the taxi drivers spent more time in the job.
• According to the MRI scans, The hippocampus changed
its structure to accommodate their huge amount of
navigating experience.
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Magnetic Resonance
Imaging
Connection of study to question
• By using an MRI, Maguire was able to observe the
structures in the brain and find a correlation between
environmental enrichment on neuroplasticity, a
physiological process occurring in the brain, particularly
around the hippocampal region which then affects
behavior in terms of memory.
• Maguire used MRI scans to investigate the structure of
the hippocampi, which would not be able to be seen
using other technologies such as an EEG or a PET scan.
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Things to discuss
• What are the strengths/limitations of using brain imaging
technology.
• How are other ways in which a psychologist at this level
of analysis may benefit from various technologies (i.e.
EEG, fMRI, etc.)
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Other Technologies
• Magnetoencephalography
(MEG) maps brain activity by
measuring magnetic fields
that are generated by
neural activity in the brain. It
is used to investigate the
basis of sensory processing
and motor planning in the
brain.
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Other Technologies
• Positron Emission Tomography
(PET) measures physiological
functioning in the brain.
• It provided the first
opportunity to explore the
parts of the brain that were
activated in undertaking
specific tasks; now it is
primarily used to study
neurotransmitters, actions of
pharmaceutical drugs, and
the expression of specific
genes in the brain.
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Other Technologies
• Functional MRI (fMRI)
shows the brain in action. It
is a highly sensitive but
indirect measure that is
used to elucidate
processes involved in
higher cognitive
functioning, including
identification of motor and
task activation areas; and
reorganization of function
• following injury to a single
brain area
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Questions?
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