Myles Jones - Lecture 1 - Cerebral Blood Flow and Psychology

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What is Myles Jones lecture 1 about?
Cerebral Blood Flow and Psychology
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Cerebral Blood Flow - ...% of the body's mass but consumes approximately ...% of the body's energy
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What are the three Cerebral Artery's
Anterior; Middle; Posterior
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What's cerebral blood flow got to do with psychology?
'Blood very likely may rush to each region of the cortex according as it is most active, but of this we know nothing.' - William James (1890) - One of the first psychologists was interested in it! But it's more important today!
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What is cognitive neuroscience?
'the branch of neuroscience that studies the biological foundations of mental phenomena'
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What is learning objective 1?
To understand why neuroimaging techniques are important for psychologists
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What is learning objective 2?
To understand how these techniques work?
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What is learning objective 3?
To understand the limitations of these techniques and what they actually measure
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What are the three neuroimaging techniques?
EEG (Electroencephalogram); Positron Emission Tomography (PET); Magnetic Resonance Imaging (MRI)
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How can we measure neural activity?
Measurements made using technique of electro-physiology - An electrode, inserted into a neutron, measures electrical activity. Activity is that of a SINGLE neuron. Stimulus projected on screen -> Microelectrode -> Amplifier -> Oscilloscope
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What is problem 1?
Animal models of higher cognitive abilities (e.g. playing a musical instrument) are difficult to find!
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What is problem 2?
Can't stick electrodes in humans brains (under normal circumstances) - Even if we could we'd only get a small amount of the brain's neutrons (and we don't know which brain regions will be involved yet)!
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What is EEG (Electroencephalogram)
Stick electrodes on the scalp; Raw data from each electrode; Trial Averaged Waveform
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What are the strengths of EEG?
Good temporal resolution
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What are the weaknesses of EEG?
Poor spatial resolution (N.B. not because of how many electrodes you can get on the head - brain waves go all over the place and add up and cancel out!); Difficult to interpret
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Are there other localised 'changes' in the brain that occur with neural activity that may be easier to detect? Hint: Brain activity uses energy!
Cerebral Glucose use; Oxygen consumption???; Cerebral blood flow
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But how can we measure cerebral glucose use, oxygen consumption and cerebral blood flow?
Positron Emission Tomography (PET)
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What is PET?
Inject radioactive tracers into the blood (I.V.) and see where they end up!
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Stages in PET?
Inject radioactive water - used to measure cerebral blood flow (CBF); The water stays in the brain and the amount there is proportional to the flow to that region; More radioactivity = more flow
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What did Raichle and colleagues do?
Used PET to measure cerebral blood flow. They activated visual cortex by presenting a visual stimulus. Saw a large focal increase in CBF.
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What are the stages in using blood flow to work out which brain areas are active and measuring this with Positron Emission Tomography (PET)?
Stimulus/task -> Brain Activity -> Focal Blood Flow increases -> PET
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What are the strengths of PET?
Gives you measurements in absolute units
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What are the weaknesses of PET?
Poor temporal resolution; Poor spatial resolution; Radioactivity means can't retest the same subjects too much
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Does Magnetic Resonance Imaging (MRI) have radioactivity or no radioactivity?
No radioactivity
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Cerebral Blood Flow - ...% of the body's mass but consumes approximately ...% of the body's energy

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What are the three Cerebral Artery's

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What's cerebral blood flow got to do with psychology?

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