College aantekeningen Cognitive Neurosciences deeltentamen 1: H1-H6
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Course
Cognitive Neurosciences
Institution
Universiteit Utrecht (UU)
Dit is een samenvatting voor cognitive neurosciences, voornamelijk de college aantekeningen, maar ook een aantal belangrijke aspecten uit het boek zijn erin verwerkt. Succes met leren!
Lecture 1
Introduction & EEG
History of neuroscience:
- Frans Joseph Gall ‘surface of the head depends on mental skills’
o Measuring enlargements and indentations of the skull (inkepingen en hobbels)
Phrenology: characteristics depending on the skull.
Modern neuroscience: is cognitive neuroscience a modern form of phrenology?
- Yes: function differentiation
- No:
o Functions defined by experimentation
o Multidisciplinary research
o Not just the size of the head – neuronal activity, measure effect of brain damage,
measure anatomy and structure etc.
Brain anatomy: first who created a map was Brodmann = Brodmann area’s
- Map was based on cell types (connections and neurotransmitters) – 43x (each neuron has a
different type of structure, while some aspects stay the same)
- Stroke -> consequences for behaviour
o Ischemic stroke: clot stops blood supply to an area of the brain
o Hemorrhagic stroke: hemorrhage/blood leaks into brain tissue
- Tumors or infection
- Neuronal degeneration
- Action potentials (electrophysiology)
- Local field potentials (electrophysiology)
Both are invasive! + searching for activity of one neuron/groups of neurons, determining
role of specific neuron/group
- Electromagnetic fields at scalp (EEG/MEG)
- Manipulating neural activity (TMS/tDCS)
o TMS can locate more local regions than tDCS, but is less safe
- Blood oxygenation (fMRI; PET; fNIRS)
o fMRI: high spatial resolution, low temporal resolution
brain computation: making models of the brain to improve applications (facebook, google)
- example of perception model -> starting with responding to edges and then later recognising
it’s a cat
- object classifier: a machine for sorting out the constituents of a substance
summary cognitive neuroscience: defining steps/networks in information processes by using
scientific methods -> study methods to measure and manipulate the brain + study cognitive
functions.
, EEG methods
EEG: ElectroEncephaloGraphy
- what does it measure?
o Differences in voltage across the scalp
o Reflects post-synaptic potentials: difference in voltage along axons
o No distinction between excitation and inhibition
Reflects LFP = local field potential
not single actions potentials, but a summation of neurons -> you need thousands of
polarity changes (local field) in neurons before an electrode can detect
- When is it a good measure?
1. Mass activity: many neurons with the SAME alignment
2. Synchronized activity: not individual action potentials
3. Close to the scalp
4. No noise sources
- Note: the more the better is NOT true!
Advantages: EEG (ERP-event related potentials) versus MEG
- Electroencephalography (EEG) -> voltage potentials = measure brain states
o Measures brain states – frequencies
o Measures temporal characteristics of brain processes (Event Related Potentials)
o Most sensitive to Gyri
Relative cheap, measures more neurons
- Magnetoencephalography (MEG) -> magnetic fields = measure brain event
o Similar measure
o Better localization (less distortions by skull)
o Most sensitive to activity originating from sulci – deeper areas
Expensive, better localization
When to use EEG?
- Brain states or effects over time at high resolution
- In some cases useful for localization of neural loci (specific place where something occurs or
is situated)
Summary (dis)advantages of EEG (MEG)
- Advantage: great temporal resolution
- Disadvantage: spatial resolution = okay
o BUT: skull blocks information
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