ERPs and Attention

Question 1

who conducted the first human EEG recording

Answer 1

Hans Berger 1942

Question 2

what is the most important difference between EEG?ERPs and TMS?

Answer 2

Manipulation vs measurement
–> in TMS you can manipulate different areas of the brain, in EEG you just have raw data and can measure activity when person does things

Question 3

odd numbers on EEG electrodes represent what hemisphere?

Answer 3

odd = left hemi 
even = right

Question 4

what cells are measured with ERPs?

Answer 4

cortical pyramidal cell (basic input out cell of cerebral cortex)
–> measures post activation potential (flow from dendrite to dendrite)

Question 5

what is the net charge outside a cell

Answer 5

negative

Question 6

the current flows through the cell completing the circuit.

-> polarity reverses with? (2)

Answer 6

• inhibitory transmitter

- PSP on cell body and basal dendrites

Question 7

polarity at the scalp depends on?

Answer 7

orientation of the cortical surface ad position of reference electrode

Question 8

what is the collective electrical field generated by multiple activated neurons called?

Answer 8

equivalent current dipole

Question 9

scalp- recorded potentials are possibly only for _______ structures with consistent _______, primarily ______ cortex

Answer 9

• layered, orientations

- cerebral

Question 10

voltages spread through the brain by _______ ________ nearly at the speed of light. Voltage everywhere except at _________ - _________ transition
–> skull causes lateral spread (like spraying hose on cardboard)

Answer 10

• volume conduction

- positive - negative

Question 11

delta waves are at what frequency and related to what?

Answer 11

• 1-3 Hz

- slow wave sleep

Question 12

theta waves are at what frequency and related to what?

Answer 12

• 4-7 Hz

- non-REM sleep, misc cognitive

Question 13

alpha waves are at what frequency and related to what?

Answer 13

• 8-12 Hz

- awake, relaxed, (zoning)

Question 14

Beta waves are at what frequency and related to what?

Answer 14

• 12-25 Hz

- mentally active

Question 15

gamma waves are at what frequency and related to what?

Answer 15

• 25 + Hz

- Local synchrony

Question 16

7 ERP components

Answer 16

1. visual sensory
2. auditory sensory,
3. P3 family
4. N2 family
5. Mismatch negativity (MMN)
6. Langauge Related (N400)
7. Response related : lateralized readiness potential (LRP), error- related negativity (ERN)

Question 17

extrastriette cortex, sensitive to visual features, arousal, attention

Answer 17

P1 (the first big positivity)

Question 18

extrastriate cortex, parietal, and fontal sub components, sensitive to attention, N170 is a sub component

Answer 18

N1 (the first big negativity)

Question 19

Brainstem auditory evoked responses (BAERs; aka auditory brain stem responses or ABRs)

• -> modulated by ?
• -> brain region?

Answer 19

• brief clicks used as stimuli

- cochlea, auditory nerve, brainstem nuclei

Question 20

Midlatency responses (MLRs)

• brain regions?
• modulated by?

Answer 20

• medial geniculate nucleus and primary auditory cortex

- highly focused attention

Question 21

auditory “long latency” sensory responses

• subcomponents?
• sensitive to?

Answer 21

• at least 3 NI subcomponents

- attention

Question 22

P3 amplitude depends on?
P3 effects cannot occur until after?
P3 latency is tied to?

Answer 22

• probability of the task defined stimulus category
• categorization
• to the amount of time required to perceive and categorize a stimulus (stimulus evaluation time)

Question 23

tells us about at what point in time we see differences in processing a right visual field target versus a left

Answer 23

N2pc

Question 24

elicited by an auditory stimulus that physically mismatches preceding stimuli

Answer 24

mismatch negativity (MMN)

Question 25

what wave is associated with meaning of a word not fitting in with the context.

Answer 25

N400

Question 26

risks and discomforts of EEG

Answer 26

• none

- net or cap on head, gel /saline in hair, remain still.

Question 27

what are ERPs good for? (3)

Answer 27

1. Determine whether an experimental manipulation
   influenced Process A or Process B
   - What was the onset time of the difference?
   - Which ERP component was affected by the manipulation?
2. Identifying multiple neurocognitive processes
   - A given behavioral effect is often accompanied by multiple
   ERP effects (different components)
   - Easy to identify multiple processes contributing to behavior
3. Covert monitoring of processing
   - Processing can be measured without a behavioral response
   (or from subjects who cannot easily respond)
   - Did the brain do something that was not evident in behavior?

Question 28

ERPs may be bad when… (5)

Answer 28

1. You desire certainty about the neuroanatomical locus of
   an effect
2. You are interested in activity that is slow (>~2 s) or not
   time-locked to a sudden, observable event
3. You cannot collect large numbers of trials in each critical
   condition
   - Long period of time between trials
   - Severe adaptation of response over trials
   - Need to surprise subjects
4. The process of interest does not have an ERP signature
5. Subjects make frequent head, eye, or mouth
   movements during the time period of interest
   - Speech is particularly bad (tongue has strong dipole)

Question 29

attention is applied by _____ modulation

Answer 29

top - down (executive function)

Question 30

what ERP component is affected by the attentional blink?

Answer 30

P3