Part I: EventRelated Brain Potentials and Behavior I - PowerPoint PPT Presentation

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Part I: EventRelated Brain Potentials and Behavior I

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Auditory Stimulation (sounds and words) Evaluative Categorizations ... Sensation and ERPs. Attention and ERPs. Perception and ERPs. Intelligence ... – PowerPoint PPT presentation

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Title: Part I: EventRelated Brain Potentials and Behavior I


1
Part I Event-Related Brain Potentials and
Behavior I
2
(ERP) Event-Related Potentials
  • A variety of brain responses that show stable
    time relationships to actual or anticipated
    stimuli
  • Endogenous produced by internal events occur
    independently of external stimuli.
  • Exogenous produced as a reaction to specific
    external events.

3
4 types of ERPs
  • Sensory
  • Motor
  • Long-Latency
  • Steady Potential Shifts (SPS)

4
How do I find the ERP?
  • Derived from EEG
  • Usually smaller than the background EEG activity
  • Evoked potential extracted from the EEG via
    averaging technique
  • Computer sums it up

5
  • Reaction time (RT) a function of many factors,
    including stimulus intensity. Quick reactions are
    related to shorter ERP latencies.
  • Bisensory stimulation the simultaneous, or near
    simultaneous stimulation of two sensory systems

6
Movement Related Potentials
  • Brain responds both before and after
  • Impulses from 2 senses an interact to influence
    ERPs recorded at the cortex

7
Asymmetries with
  • Visual Stimulation
  • Auditory Stimulation (sounds and words)
  • Evaluative Categorizations
  • Cognitive functions (intelligence, verbal and
    spatial tasks)
  • Drama drama!!

8
Wake up kids! The ERP and Sleep
  • Classification of sleep stages discussed on
    Monday enable us to study ERPs as a function of
    these stages

9
Overall findings regarding ERPs during sleep
indicate
  • That they exist

10
Part IIEvent-Related Slow Brain Potentials and
Behavior
11
Slow Potentials
  • Also known as slow waves
  • Take longer to develop than sensory-evoked
    potentials or motor potentials
  • Endogenous in nature
  • Produced by internal processes vs. outside stimuli

12
Types of Slow Potentials
  • Contingent Negative Variation (CNV)- effected by
    the expectancies of stimuli
  • Readiness Potential (RP)- involved in the
    intention to move
  • P300 (P3)- involved in decisions

13
Contingent Negative Variation (CNV)
  • Steady negative shift in brain activity
  • Occurs when there is an initial stimulus (S1)
    followed by a second stimulus (S2) that requires
    a response from the participant

14
Two Shapes of CNV
  • Type A- fast rise time
  • Generally occur when participants are unsure when
    S2 will be presented
  • Type B- slow rise time
  • Occurs when participants are more certain of when
    S2 will be presented

15
Waves Seen in CNV
  • Orientation Wave (O wave)
  • Evident about 650 msec after S1
  • Expectancy Wave (E wave)
  • Occurs at the end of the interstimulus interval
    (ISI)

16
Type A vs. Type B
17
Sexual Preference Study
  • Performed by Costell, Lunde, Kopell, Wittner
    (1972)
  • Both genders showed larger CNVs when presented
    with stimuli of the opposite sex
  • Large CNVs were also present for the
    anticipation of opposite sex stimuli
  • CNV was found to be a useful index of sexual
    preference in college students
  • It has been suggested to use CNVs when
    prosecuting sex offenders to determine sexual
    object preference

18
Readiness Potential (RP)
  • Also referred to as a Bereitschaftspotential
  • Slow rising negative wave
  • Begins 500-1,000 msec before voluntary movement
    and peaks at time of movement
  • Also precedes spontaneous movements

19
Piano study
  • Participants had at least 20 years of experience
  • Compared RPs between playing a single note and
    playing a melody
  • RPs were higher in amplitude and started earlier
    when playing the melody
  • Also found that frontal areas were stimulated
    before the motor areas showing that the
    movements may begin in the frontal cortex before
    they are initiated in the motor cortex

20
P300 Potential (P3)
  • ERP wave that occurs about 300 msec after
    stimulation
  • Associated with cognitive activities
  • Decision making, attention, and discrimination
    are a few examples
  • Task-relevant wave more confidence in the task
    appears to yield a higher wave amplitude

21
Uses of P300
  • Hereditary Component
  • People with certain psychiatric disorders are
    found to have smaller amplitudes and longer
    latency P300s
  • Schizophrenia and Alcoholism
  • Suggests a possible genetic marker that could be
    used to predict psychiatric disorder in a person
  • Research on memory- P300 has a much larger
    amplitude with previously learned material vs.
    new material

22
Part III Event-Related Brain Potentials and
Behavior II
23
Human mental processes related to event related
potentials (ERPs)
  • Intelligence
  • Stimulus meaning and emotional content
  • Linguistic processes
  • Classical and operant conditioning
  • Sensation and ERPs
  • Attention and ERPs
  • Perception and ERPs

24
Intelligence
  • The Neural Efficiency Hypothesis
  • Latencies of ERP may be an index of information
    processing efficiency
  • The String Hypothesis
  • IQ is positively related to complexity of ERP
    trace
  • P300 and Intelligence
  • Examined P300 response as a link to intelligence
  • Possible unbiased measure of intelligence?

25
Stimulus meaning and emotional content
  • Meaningfulness of stimuli alters the ERP
  • Stimulus content, affective value, and
    expectancies
  • Emotional effects when presented with different
    stimuli
  • Two hemispheres appear to cooperate when
    processing emotional facial expressions

26
Linguistic processes
  • Sounds produce larger P300 amplitudes than words
  • P300 system is engaged whenever task-related
    language stimuli are used
  • N400 and semantic mismatch

27
Conditioning and ERPs
  • Classical conditioning
  • Comparison between pairing stimuli and subsequent
    ERPs
  • Operant conditioning

28
Sensation and ERPs
  • Smell
  • ERPs elicited by stimulation of olfactory
    receptors
  • Taste
  • ERPs only visible with salt and sour tastes
  • Touch and Pain

29
Attention and ERPs
  • Selectivity in attention
  • Mismatch negativity
  • ERP amplitude higher in response to deviant
    stimuli presented in an attended ear than to the
    unattended ear

30
Attention and ERPs (cont.)
  • Intermodal vs. intramodal selective attention
  • Different brain mechanisms may be involved in
    selecting auditory stimuli from other auditory
    stimuli (intramodal) as opposed to selecting
    auditory stimuli from visual stimuli (intermodal)
  • Resource allocation

31
Perception and ERPs
  • Relationships between ERPs and perceptions
    including
  • Shape
  • Pattern size
  • Blurring and pattern perception
  • Upper and lower visual fields
  • Perceptual discrimination and P300
  • Corners
  • Orientation of figures
  • Visual masking
  • Color

32
Reference
  • Andreassi, J.L. (2000). Psychophysiology Human
    Behavior Physiological Response. Mahwah, NJ
    Lawrence Erlbaum Associates.
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