Methods for Studying the Brain

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  • Created by: Yasmetron
  • Created on: 26-02-23 17:38
What is the localist view?
• The brain is composed of specialised areas.
• Information processing in each of these is local and specific.
• Discrete areas are responsible for discrete functions.
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What is the anti-localist view?
• The brain is a collection of networks.
• Information processing is distributed.
• All areas are equally responsible for all functions.
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What is functional segregation?
How does function emerge from specialised information processing in individual brain areas? – how can we separate function.
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What is functional integration?
How does function emerge from distributed information processing across the networks of these areas? – how different areas of a specific section completes different functions.
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What is brain architecture?
comprised of billions of connections between individual neurons across different areas of the brain. These connections enable lightning-fast communication among neurons that specialize in different kinds of brain functions.
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What is brain activity?
the ability to perform a given cognitive or physiological task.
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What is brain stimulation?
stimulation of specific areas of the brain as a means of determining their functions and their effects on behaviour and as a therapeutic technique.
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What is cytoarchitecture?
• The cellular composition of the cortex varies.
• They way that information is processed across the cortex therefore cannot be uniform.
• Mapping the variation can distinguish cortical areas involved in different forms of information processing.
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what is connectivity?
• The flow of information across brain networks is an integral part of information processing in the brain.
• architecture of networks is important for understanding the relationships between neural and cognitive processes.
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How does diffusion tensor imaging work?
• Diffusion of a water molecule within a fibre bundle.
• Diffusion is less restricted along the axis of the fibre bundle than across it.
• This helps us find the direction of axons lined up together.
• Reconstructions of major fibre bundles
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How does behavioural neurophysiology work?
• Electrodes are inserted into or directly onto a small area of the brain.
• Single-unit recordings: recording the activity of individual neurons.
• Multi-unit recordings: recording summed activity from small populations of neurons.
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What are the positives and negatives of behavioural neurophysiology?
• Advantages: important in animal studies for determining exactly where the signal is coming from, at very high temporal spatial resolution
• Disadvantages: doesn’t work on humans because they cannot stick the electrodes in the brain
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How does Electroencephalography (EEG) work?
• EPs produced by single neurons are small, but when several neurons are actively together, the resulting signal can be measured on the scalp
• By averaging the traces to cancel out noise, we can detect EEG responses that are specific to particular sign
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What are the positives and negatives of EEGs?
Advantage: non-invasive, high temporal resolution
Disadvantage: but the spatial resolution is relatively poor because of the way that the signal is distorted by the tissue between the brain and the electrode.
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How does Magnetoencephalography (MEG) work?
• MEG measures the magnetic signal changes that result from changes in electrical potential
• The detectors, called SQUIDs (superconducting quantum interference device) are very sensitive to these signals
• can measure the same types of oscillation.
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What are the positives and negatives of MEG?
Advantages: MEG has a very high temporal resolution , and in addition has better spatial resolution (around 1cm and less) because magnetic singles are not distorted as in EEG.
Disadvantages:The sensitivity and therefore the spatial resolution of MEG sourc
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How does Magnetic Resonance Imaging (MRI) work?
the magnetic field temporarily realigns water molecules in your body. Radio waves cause these aligned atoms to produce faint signals, which are used to create cross-sectional MRI images
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What are the positives and negatives of MRI?
Advantages: safe, high temporal and spatial resolution,
Disadvantages: restrictive, takes a long time, expensive
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How does Functional Magnetic Resonance Imaging (fMRI) work?
• BOLD = blood oxygen level dependent effect
• When neurons are active, the amount of oxyhaemoglobin in the blood increases
• fMRI of a subject viewing a visual stimulus detects higher blood-oxygen levels in the visual cortex.
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What are the positives and negatives of fMRI?
Advantages: higher spatial resolution than EEG and MEG
Disadvantage: lower temporal resolution (in order of seconds)
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How does Transcranial Magnetic Stimulation (TMS) work?
• Brief and rapidly changing high intensity electrical current is passed through loop of conducting wire onto an area of the scalp.
• Generates a powerful magnetic field that is capable of inducing an electric current in excitable tissue.
• Applied onto
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What are the positives and negatives of TMS?
Advantages: target very specific processes that occur at particular time points in experiments.
Disadvantages: discomfort, headache, takes a lot of time, expensive
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How does Deep Brain Stimulation (DBS) work?
• Purpose: Stimulation of specific parts of the brain (e.g. specific areas within the basal ganglia) alleviate the symptoms of particular disorders
• Method: Electrodes are implanted into specific subcortical areas and connected to implanted stimulators
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What are the positives and negatives of DBS?
Positives: DBS trials for Parkinson’s disease have shown substantial improvements in symptoms, as measured by motor and daily living scores.
Negatives: dizziness, headache, difficulty concentrating, temporary pain
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Other cards in this set

Card 2

Front

What is the anti-localist view?

Back

• The brain is a collection of networks.
• Information processing is distributed.
• All areas are equally responsible for all functions.

Card 3

Front

What is functional segregation?

Back

Preview of the front of card 3

Card 4

Front

What is functional integration?

Back

Preview of the front of card 4

Card 5

Front

What is brain architecture?

Back

Preview of the front of card 5
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