Tools to study to brain Flashcards
What are mental representations of stimuli?
The way that properties of objects are interpreted by cognition.
What are neural representations of stimuli?
The way that properties of objects manifest themselves in neural signals.
What are grandmother cells?
Refers to the idea that specific neurons fire in response to specific stimuli. e.g a ‘grandmother’ neuron that fires every time you see your grandmother.
Define rate coding.
The rate of a neuron’s firing can code for information such as stimulus strength.
Define temporal coding.
The synchrony of firing between several different neurons. (neurons that fire together bind together information. e.g a blue circular object moving from left to right)
What are single cell recordings?
The use of very small electrodes to measure activity from individual neurons.
What are the two types of single cell recordings?
Intracellular - neural activity from within the axon
Extracellular - neural activity from outside the axon.
What does EEG stand for?
Electroencephalography.
What do EEGs do?
Record electrical activity of neurons in real-time.
When and who conducted the first EEG in humans?
Hans Berger in 1924
What exactly does EEG measure?
Changes in voltage on the scalp which represent the summed activity of millions of neurons underneath each electrode.
What are two strengths of using EEGs to measure brain activity?
+ Very good temporal resolution
+ Transportable and cheap.
What is one limitation of using EEGs to measure brain activity?
- Poor spatial resolution
What does ERP stand for?
Event-related potential.
What are ERPs?
The average waveform that is generated when EEG responses to the same stimulus are measured several times over.
What are the names of the different frequencies that brain oscillations occur at?
- Delta
- Theta
- Alpha
- Beta
- Gamma
Which frequencies do delta waves operate at?
0.5Hz - 4Hz
Which frequencies do theta waves operate at?
4Hz - 8Hz
Which frequencies do alpha waves operate at?
8Hz - 12Hz
Which frequencies do beta waves operate at?
13Hz-30Hz
Which frequencies do gamma waves operate at?
30Hz-100Hz
True or false: Different patterns of oscillations can reveal the state that the participant is in (asleep, awake, relaxed, aroused, etc)
True.
What does MRI stand for?
Magnetic Resonance Imaging
How does MRI work? (6 steps)
- Initially, H+ protons in the brain all face different directions.
- A magnetic field is applied, which causes almost all of the protons to align.
- A radio wave is then sent across the brain which flips the protons into the opposite direction.
- The protons immediately return to the direction they were facing before the radio wave was applied.
- Protons in grey matter, white matter or in CSF take different amounts of time to revert to their original orientation.
- The different structures can be seen on the MRI scan.