Module 2 Flashcards
What is EEG?
Electroencephalography. It measures the movement of ions inside, across, and outside neural cell membranes.
What is an ERP?
An event related potential. AKA electrical changes as a result of a stimulus/making a movement.
How is the ERP extracted?
Taking the average of ‘time locked’ slices of multiple trials.
What is the CNV?
The contingent negative variation. It is dependent on action anticipation.
What is the RP?
Volitional preparation and initiation - or the readiness potential. Extracted when movements are volitional.
What is the LRP?
The lateralized readiness potential. We can use this to determine when we decide which hand to use in a movement.
How does the length of the foreperiod affect the CNV?
No CNV will develop if the foreperiod is too short.
If the foreperiod is too long, the CNV will flatten quickly. A state of anticipation is hard to maintain.
What is premotoric processing?
Pre-motor processing between stimulus onset and LRP onset (encompasses SI and RS).
What is motoric processing?
Pre-motor processing between the LRP and EMG onset (programming).
What is stimulus locked LRP?
Time locking the LRP to the onset of the stimulus. This tells us how long SI and RS take.
What is response-locked LRP?
Time locking the LRP to the response, and interpreting how long it took to get there. Measures length of the response programming stage.
LRP onset occurs at what stage of information processing?
After response selection.
What happens to the CNV when we know more precues to a task?
It increases. More information = more anticipation.
What happens to the LRP if we know more precues to a task?
It is larger during the foreperiod, as you already know which hand to use.
What is the same/different about the LRPs of compatible and incompatible mappings?
Processing stage/onset is the same (no difference in SI and RS).
Incompatible LRP goes in the wrong direction, then corrects. This is due to the wrong hand being anticipated first.
Why do compatible and incompatible LRPs start at the same time?
Dual process model: automatic process finishes first.
What is TMS, and what does it measure?
Transcranial magnetic stimulation.
By magnetically stimulating cortex neurons, an EMG response is recorded in the muscle.
What is the MEP?
Motor evoked potential. It is the EMG response in the muscle as a result of TMS stimulation.
What is the silent period (SP)?
The refractory period and activation of inhibitory interneurons of the motor cortex. Needs background activity to be observed.
What is the Hoffman reflex (H-reflex)?
Direct electrical activation of an afferent nerve.
What does the M-wave represent?
The size of the electrical stimulus by the H-reflex.
What does the H-wave represent?
Indicates the size of the reflex response to a given stimulus. AKA the size of the muscle response.
What is sub-threshold TMS?
TMS is added to existing excitability in order to produce a twitch. The goal is not to produce a twitch directly from TMS.
What happens to an MEP if there is a long foreperiod?
MEP does not vary. SP is longer, as we are waiting longer for activation.
What happens to an MEP if there is a short foreperiod?
A smaller MEP, which indicates inhibition.
A shorter silent period, which means more activation.
Why is there both inhibition and activation when a foreperiod is short?
Both excitatory and inhibitory neurons are inhibited during preparation.
Inhibit the excitatory neurons -> get a smaller MEP.
Inhibit the inhibitory neurons -> shorter SP, more excitation.
Why is there MEP suppression during movement preparation?
In order to not preemptively make a response.
