Cognitive neuroscience Hoorcollege aantekeningen
Lecture 1: Introduction & EEG Methods
Cognitive neuroscience = a combination between cognition and neuroscience.
Cognition:
- Visual perception
- Auditory perception
- All cognitive skills…
Neuroscience: How does all these cognitive processes work and how do we measure these
processes. Alle cognitieve processen komen voort vanuit de hersenen, dus hersenactiviteit
proberen te meten.
- EEG/MEG
- fMRI
- etc.
History of neuroscience:
- Franz Joseph Gall suggested that surface of the head depend on mental skills.
- Different areas on the skull each represent a different skill.
- Measure enlargements or indentations of the skull.
Phrenology (= de leer volgens welke aan de schedel de karaktereigenschappen van de mens
zouden zijn af te lezen):
- Instinct for reproduction
- Love for offspring
- Affection & friendship
Brain anatomy: Many different types of cells, connections, and neurotransmitters.
Brodmann was the first to map the cortex based on cell types. -> more detailed maps
followed later.
Each neuron type has a different function.
The structure in the brain says something about its function.
,Neurons = different from normal cells:
- Axon & dendrites are specialized structures to transmit and receive information
through action potentials.
- They tend not to reproduce after birth. The connections do alter.
- Each cell type has its own specialized function.
Damage to anatomy (clinical neuropsychology)
- Stroke
Hemorrhagic stroke = Hemorrhage/blood leaks into brain tissue
Ischemic stroke = Clot stops blood supply to an area of the brain.
- Tumors or infections (or insects) = sometimes they just affects the neurons, or
sometimes they push away the tissue.
- Neural degeneration (multiple sclerosis, Alzheimer’s)
- Trauma (football)
- Epilepsy & lesions
- Genetic manifestations
Measuring brain activity:
- Action potentials (electrophysiology)
- Local field potentials (electrophysiology)
- Electromagnetic fields at scalp (EEG/MEG)
- Manipulating neural activity (TMS/tDCS)
- Blood oxygenation (fMRI; PET; fNIRS)
, Summary cognitive neuroscience: Defining steps/networks in information processes by using
neuroscientific methods.
Study methods to measure and manipulate the brain
Study cognitive functions
EEG = Electro-encephalography -> The continuous recording of brain activity
What is that EEG is recording?
- Electro = electromagnetic fields
- Encephalo = related to the brain
- Graphy = descriptive science
EEG: what does it measure? Measuring potential differences due to neural activity.
- Differences in voltage across the scalp
- Reflects post-synaptic potentials (PSP): difference in voltage along axons.
- Both inhibitory (-) and excitatory (+) PSP!
- Reflects local field potential -> not single action potentials but a summation of many
neurons. A single action potential is not strong enough to measure.
When is the measurement good?
- Mass activity: many neurons with the same alignment
- Synchronized activity: Not individual action potentials
- Close to the scalp: Scalp & Skull is not a good conductor -> smears out the signal
- No noise sources: electronic devices -> Artefacts in the data
32-64 electrodes = enough for P100, N200, P3 etc.
128 electrodes = enough for localization
Lecture 1: Introduction & EEG Methods
Cognitive neuroscience = a combination between cognition and neuroscience.
Cognition:
- Visual perception
- Auditory perception
- All cognitive skills…
Neuroscience: How does all these cognitive processes work and how do we measure these
processes. Alle cognitieve processen komen voort vanuit de hersenen, dus hersenactiviteit
proberen te meten.
- EEG/MEG
- fMRI
- etc.
History of neuroscience:
- Franz Joseph Gall suggested that surface of the head depend on mental skills.
- Different areas on the skull each represent a different skill.
- Measure enlargements or indentations of the skull.
Phrenology (= de leer volgens welke aan de schedel de karaktereigenschappen van de mens
zouden zijn af te lezen):
- Instinct for reproduction
- Love for offspring
- Affection & friendship
Brain anatomy: Many different types of cells, connections, and neurotransmitters.
Brodmann was the first to map the cortex based on cell types. -> more detailed maps
followed later.
Each neuron type has a different function.
The structure in the brain says something about its function.
,Neurons = different from normal cells:
- Axon & dendrites are specialized structures to transmit and receive information
through action potentials.
- They tend not to reproduce after birth. The connections do alter.
- Each cell type has its own specialized function.
Damage to anatomy (clinical neuropsychology)
- Stroke
Hemorrhagic stroke = Hemorrhage/blood leaks into brain tissue
Ischemic stroke = Clot stops blood supply to an area of the brain.
- Tumors or infections (or insects) = sometimes they just affects the neurons, or
sometimes they push away the tissue.
- Neural degeneration (multiple sclerosis, Alzheimer’s)
- Trauma (football)
- Epilepsy & lesions
- Genetic manifestations
Measuring brain activity:
- Action potentials (electrophysiology)
- Local field potentials (electrophysiology)
- Electromagnetic fields at scalp (EEG/MEG)
- Manipulating neural activity (TMS/tDCS)
- Blood oxygenation (fMRI; PET; fNIRS)
, Summary cognitive neuroscience: Defining steps/networks in information processes by using
neuroscientific methods.
Study methods to measure and manipulate the brain
Study cognitive functions
EEG = Electro-encephalography -> The continuous recording of brain activity
What is that EEG is recording?
- Electro = electromagnetic fields
- Encephalo = related to the brain
- Graphy = descriptive science
EEG: what does it measure? Measuring potential differences due to neural activity.
- Differences in voltage across the scalp
- Reflects post-synaptic potentials (PSP): difference in voltage along axons.
- Both inhibitory (-) and excitatory (+) PSP!
- Reflects local field potential -> not single action potentials but a summation of many
neurons. A single action potential is not strong enough to measure.
When is the measurement good?
- Mass activity: many neurons with the same alignment
- Synchronized activity: Not individual action potentials
- Close to the scalp: Scalp & Skull is not a good conductor -> smears out the signal
- No noise sources: electronic devices -> Artefacts in the data
32-64 electrodes = enough for P100, N200, P3 etc.
128 electrodes = enough for localization
