(5) Techniques in Neuroscience Flashcards
What is electrophysiology?
The branch of physiology that deals with the electrical phenomena associated with nervous and other bodily activity
What is Single-unit recording in terms of electrophysiology?
studies the electrical activity of individual neuron, the use of an electrode to record the electrophysiological activity (action potentials) from a single neuron
What is Multi-unit recording in terms of electrophysiology?
studies the composite electrical activity of groups of neurons (e.g., fibre pathway)
What is an EEG recording in terms of electrophysiology?
studies the low frequency, composite electrical activity of unspecified origin at select brain regions, EEG measures the activity of large numbers (populations) of neurons
How does single-unit recording work?
- An electrode is introduced into the brain of a living animal
- It detects electrical activity generated by the neuron adjacent to the electrode tip
- The animal is usually immobilized, but awake
- Enable researchers to understand how individual neurons code information
- No pain receptors in the cortex
What did Rizzolatti et al find out about neurons and performance? (single-unit recording)
- Neurones activates both while observing and while performing:
- Actions such as grasping
- Emotions such as sadness
- Watching someone receive painful events such as shocks
How does EEG work?
- EEG is non-invasive and painless
- Electrodes measure voltage-differences at the scalp in the microvolt (μV) range
- Voltages are recorded with millisecond resolution
Why is EEG used?
- Detecting changes in brain patterns
- Can average several readings to obtain evoked potential
- Often used for detecting epilepsy and other brain disorders (sleep disorders)
What is An event-related potential (ERP)?
An event-related potential (ERP) is the measured brain response that is the direct result of a specific sensory, cognitive, or motor event
How are ERPs created?
- Large background oscillations of the EEG trace make it impossible to detect the evoked response from a single trial
- By averaging from hundreds of trials, the background EEG is removed, leaving the event-related potentials
What does neural activity consume and generate?
Neural activity consumes oxygen as well as generating electrical signals
-In order to compensate for increased oxygen consumption, more blood is pumped into the active region
What is a PET?
PET measures the blood flow in a region, whereas fMRI measures the blood oxygenation
- The time taken for this response is slow (several seconds) and so functional imaging has a poor temporal resolution, but a good spatial resolution
- This is the complementary profile to EEG
How much energy does the brain consume?
The brain consumes about 20% of energy of body
How much blood flow does the brain receive?
The brain receives about 20% of blood flow
How does blood flow in neural activity change?
Neural activity increases global blood flow marginally, but dramatically locally (up to 25% change!!!!)
