.. sense in which properties of the outside world are simulated and interpreted by cognition
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Neural representations are..?
..way in which those properties of the outside world manifest themselves in the neural signal
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Rate coding is..?
greater RATE of a neurones response to code information
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Temporal coding..?
greater SYNCHRONY of the responses of several neurons is used to code information (bind together diff aspects of an image)
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How do neurones code information?
Action potential always looks the same, but rate at which neurons fire can change
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How do we represent this?
Rate coding
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What are Grandmother cells?
Neurons which have a v specific preferred stimuli and fire when responding to this stimuli (e.g. Luke Skywalker)
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Single-cell recordings, what are they?
Very small electrode records neural activity from within axon (INTRAcellular) or from outside axon membrane (EXTRAcellular)
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Electroencephalography (EEG) - what is it?
Electrical activity recorded via electrodes on the scalp (non-invasive)
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EEG measures neural activity in ________ (time)?
quasi real-time (millisecond scale)
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EEG first recorded by..?
H. Berger (1924) (in humans)
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How does EEG work?
Measure voltage changes on the scalp
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PROS of EEG
1 good time resolution (quasi real-time) / 2 transportable and cheap
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CONS of EEG
relatively poor spatial resolution
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Event-Related Potentials (ERP's) - what is it?
When stimulus presented multiple times and EEG response to task is measured over&over again - average waveform is created to generate anERP
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Brain oscillations - what are they
show as rhythmic activity in the EEG - arise if many neurons under one electrode
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MRI - basic principles
Very strong magnetic field applied across scanned area - disturb a stable magnetic alignment w/ short radio-freq pulses and measure the resulting change in magnetic field
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fMRI - what does it do
Measures BOLD - does NOT measure neural activity directly - the BOLD signal changes win response to stimulus - called the HRF
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what is the BOLD
Blood Oxygenated Level Dependent
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Limitations of fMRI
HRF = very slow takes around 5 secs to reach its peak and 10 secs to return to baseline level // only correlational - no conclusions about causation possible e
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Functional vs. Structural image
fMRI = lower spatial resolution // MRI = typically 1 full brain image / fMRI -multiple images recorded (1-4 sec each)
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Brain stimulation techniques - what
techniques used to directly influence brain activity - used to either STIMULATE or "KNOCK OUT" a given brain region and investigate the effects of this on behaviour
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TMS = ?
Method to create virtual lesions - transiently 'knock out' brain regions
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2 methods that use current flowing between 2 electrodes - cathodes and anodes
tDCS (constantly) and tACS (alternatingly)
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Other cards in this set
Card 2
Front
Mental representations are..?
Back
.. sense in which properties of the outside world are simulated and interpreted by cognition
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