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Objective 2.6: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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• 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.

Things to consider….Things to consider….

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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.

Brain Imaging Brain Imaging TechnologyTechnology

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• 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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• 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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• 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:o Electroencephalogram (EEG)o Magnetic Resonance Imaging (MRI)o Positron Emission Tomography (PET) scano Functional Magnetic Resonance Imaging (fMRI)


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Electroencephalogram (EEG)Electroencephalogram (EEG)An amplified recording of the electrical waves sweeping across the brain’s surface, measured

by electrodes placed on the scalp.

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hoto/ Photo R

esearchers, Inc.

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What does an EEG reading tell What does an EEG reading tell

you?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 The use of

Electroencephalogram (EEG) Electroencephalogram (EEG)

at the BLOAat the BLOAEEG 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 The use of

Electroencephalogram (EEG) Electroencephalogram (EEG)

at the BLOAat the BLOAThe 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

• 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.

Magnetic Resonance Magnetic Resonance ImagingImaging

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•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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•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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•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/watch?videoId=gHWjNls5OSo•


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•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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•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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•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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Researcher: Maguire et alStudy of: Short Term MemoryYear: 2000Aim: To investigate if there was structural changes in the hippocampal regions of taxi drivers


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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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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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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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• 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.)

Things to discussThings to discuss

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• 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.

Other TechnologiesOther Technologies

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• 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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• 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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