ERPs - Motor Activity, Asymmetries, Sleep & Intelligence

Question 1

Explain the relationship between ERPs and motor activity.

Answer 1

Using ERPs research has examine the response to both voluntary and involuntary movements.

• Slow negative wave beginning 1 second prior to movement (the readiness potential)
• Major premotor component is the readiness potential, major post-motor components are the N1/P2 and P300
• No pre-motion components with passive movements
• There is a correlation between the between the motor process, speed in which you activate this and the P3.

Question 2

Are ERPs sensitive to contralateral processing?

Answer 2

Yes.
Visual stimulation - the occipital area receiving primary projections from visual field stimulated show larger ERP components. Stimuli presented in the left visual field produce shorter ERP latencies at right than left occipital areas and vice versa.
- Inter-hemispheric Transfer Time: time taken for signals to cross over from primary to secondary hemisphere via the corpus callosum. Estimated to be 10-20ms. ERPs are an accurate and a direct measure as opposed to measuring reaction time.
- In two subjects born without a corpus callosum found they didn’t have the primary inter-hemispheric transfer of information

Auditory - each ear has more neuronal connections to contralateral auditory Cx

Question 3

What is the neural efficiency hypothesis?

Answer 3

Efficiency and intelligence being used interchangeably.

• Overall mixed evidence - more evidence for visual than auditory Cx. But why would neural efficiency be restricted to one sensory modality. If it a real concept it shouldn’t matter about the modality.
• Biologically efficient organisms process data quicker. ERP latencies should be shorter. Therefore ERP latency = info processing efficiency.

Question 4

Explain the string hypothesis.

Answer 4

Complexity and amplitude are related to intellectual ability. Stretch the ERP as if it were a piece of string to measure the length

• Critique: oversimplified, relies too heavily on amplitude, skull thickness attenuates amplitude
• Latency is a better predictor of intelligence
• Evidence for the string hypothesis is questionable

Question 5

Describe the link between the P300 and intelligence.

Answer 5

• Suggestions timing of the P3 are correlated to cognitive ability. Links timing, not amplitude to intelligence
• One study found that active and passive P3 latency slowed with age. P3 latency got longer
• Also found that there was no P3 to answers participants knew to be incorrect or difficult items