Lecture 1 - Introduction & EEG (Cognitive Neuroscience, UU)

Franz Joseph Gall suggested that surface of the head depends on mental skills. He is one of the firsts linking the brain to cognition.

Can modern phrenology be seen as modern cognitive neuroscience?

• Yes:
  • Functional differentiation of the brain
• No:
  • Functions are defined by thorough experimentation
  • Multidisciplinary research
  • Not just size of brain areas

Brodmann was the first to map the cortex based on cell types. More detailed maps followed later.

The structure of the brain has a reason: function.

You can measure brain activity using

• Action potentials (electrophysiology)
• local field potentials (electrophysiology)
• Electromagnetic field at scalp (EEG/MEG)
• Manipulating neural activity (TMS/tDCS)
• Blood oxygenation (fmri)

Brain elements: neurotransmitter & hormones. You can add pharmacology and food supplements.

Brain computation: making models of the brain to improve applications (facebook, google).

Cognitive neuroscience defines steps/networks in information processes by using neuroscientific methods.

EEG (ElectroEncephaloGraphy):

• Measures the 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 a single action potential but a summation of many neurons

When is the measurement good?:

• Mass activity
• Synchronized activity
• Close to the scalp

32-64 electrodes are enough to measure time effects.

Advantages EEG:

• Temporal characteristics
• ERP’s

EEG measures the voltage potentials and MEG measures the magnetic field. MEG is similar to EEG, but better localization and most sensitive to activity originating from sulci.

EEG = relatively cheap, measures more neurons.

MEG = expensive, better localization

EEG & MEG same temporal resolution, MEG better spatial resolution.

So slow waves = low arousal

Fast waves = high arousal

Gamma (32Hz>) = superlearning

Beta (16-31Hz) = processing information, analytical thinking

Alpha (8-15Hz) = Eyes closed or very relaxed

Theta (4-7Hz) = Sleep, REM, dreaming, deep meditation

Delta (<4Hz) = deep dreamless sleep

ADHD = hyperactive, but less cortical arousal

Treating ADHD = increase arousal with medicine

Each frequency reflects a different mental state.

Average ERP’s to cancel out the noise.

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