summary of lectures and literature -
neurophysiology of cognition and
behavior
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,Neurophysiology of cognition and behavior
Lecture 1
Cocktail party effect
- Subjects were presented 2 auditory streams
- Task was to repeat 1 of the 2 streams
- Subjects were able to do this and they were also able to report content of the attended
stream
- They weren’t able to report much of the unattended stream
- Experiment conducted by Cherry in 1953
Visual spatial attention
- Conducted by Helmholtz
- Subjects were briefly presented with an
array of letters
- Asked afterwards to recall the letters they
had seen
- If a subject was covertly attended to
attending to a certain area in the visual
field away from fixation, then the items in
the attended portion of the letter array
could be accurately reported
- Items in the unattended locations could
not
Information processing models of selective attention
- Model proposed by Broadbent
o Early-selection gating mechanism under top-down control determines which
information is passed on for high-level analysis
- Treisman
o Based on attenuation and/or modulation instead of all-or-non gating
- Recent models
o Possibility of top-down selection at early, middle or later stages of stimulus
processing
Studying endogenous visual spatial attention
- A centrally presented instructional cue indicates where a target
will most likely be presented (valid cue), were it will be less likely
presented (invalid cue) or no information is provided by the cue
(neutrally cued)
- Typical results show he benefits and costs in the reaction time for
target detection after valid and invalid cuing, relative to the
neutral cue
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,Exogenously triggered (reflexive) attention
- In this paradigm a brief flash is presented in one of
the two possible target locations, this serves as an
exogenous cue for a target that might follow at that
location or the other
- The occurrence of a target at cued versus non-cued
location is random (50%/50%)
- Shortly after the exogenous cue (green shaded time
period), stimulus processing at that location is
facilitated (faster response times to cued relative to
un-cued locations)
- At longer time intervals (red shaded period),
there is decrement in performance for cued
targets
o This phenomenon is known as inhibition
of return
- After Klein (2000); data from Posner and Cohen
(1984)
Early and late selection during auditory attention
- The auditory attentional stream paradigm is a
means for studying the mechanisms of auditory
selective attention
- The asterisks indicate tones that deviate slightly
from the rest of the stimuli in a particular feature
(loudness/pitch); these tones serve as targets in
the attended channel
- The effect of auditory attention on the N1 wave at
100msec in the auditory ERP (event-related
potential) is thought to reflect a relatively early
attentional selection
- The P300 effect elicited only by detected targets in the
attended channel is thought to reflect a late-selection
process to distinct elements within the attended
channel
- Diagrams B and C are from Hillyard et al. (1983)
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Dit document is auteursrechtelijk beschermd, het verspreiden van dit document is strafbaar. extra verdienen?
, Early auditory attention effects during dichotic
listening
- Even during very strongly focused auditory
spatial attention, no modulation of the
brainstem-evoked potentials (BERs) in the first
10 msecs is observed
- However, an early cortical effect is reflected as
enhanced activity from 20-50msecs for the
attended relative to the unattended tones (aka
p20-50 attention effect)
o This provides particularly strong
support for early-selection theories
- Using MEG, the p20-50 effect was indeed
localized as a local dipolar source (red arrow)
in primary auditory cortical areas on the lower
bank of the Sylvian Fissure
o This provides yet further support that
attention can affect early sensory
processing activity in the low-level
sensory cortices
- Woldorff et al. (1987)
Effects of attention on auditory feature processing as reflected by the
mismatch negativity ERP
- These overlays of the ERPs elicited by feature-deviant stimuli and
the standard (non-deviant) stimuli in the attended and he
unattended auditory streams show that the mismatch negativity
(MMN), which typically appears as increased negative-wave
activity between 150-220msecs in response to the feature-
deviating stimulus, is significantly larger in the attended
condition
- The overlay of deviance-related difference waves (deviant RP
minus non-deviant ERP for the 2 attention conditions) shows
strong effects of auditory attention on the MMN and thus on
auditory feature discrimination
- Woldorff et al. (1991)
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Dit document is auteursrechtelijk beschermd, het verspreiden van dit document is strafbaar. extra verdienen?
neurophysiology of cognition and
behavior
Gedownload door: ikarumba316 | € 912 per jaar
Dit document is auteursrechtelijk beschermd, het verspreiden van dit document is strafbaar. extra verdienen?
,Neurophysiology of cognition and behavior
Lecture 1
Cocktail party effect
- Subjects were presented 2 auditory streams
- Task was to repeat 1 of the 2 streams
- Subjects were able to do this and they were also able to report content of the attended
stream
- They weren’t able to report much of the unattended stream
- Experiment conducted by Cherry in 1953
Visual spatial attention
- Conducted by Helmholtz
- Subjects were briefly presented with an
array of letters
- Asked afterwards to recall the letters they
had seen
- If a subject was covertly attended to
attending to a certain area in the visual
field away from fixation, then the items in
the attended portion of the letter array
could be accurately reported
- Items in the unattended locations could
not
Information processing models of selective attention
- Model proposed by Broadbent
o Early-selection gating mechanism under top-down control determines which
information is passed on for high-level analysis
- Treisman
o Based on attenuation and/or modulation instead of all-or-non gating
- Recent models
o Possibility of top-down selection at early, middle or later stages of stimulus
processing
Studying endogenous visual spatial attention
- A centrally presented instructional cue indicates where a target
will most likely be presented (valid cue), were it will be less likely
presented (invalid cue) or no information is provided by the cue
(neutrally cued)
- Typical results show he benefits and costs in the reaction time for
target detection after valid and invalid cuing, relative to the
neutral cue
Gedownload door: ikarumba316 | € 912 per jaar
Dit document is auteursrechtelijk beschermd, het verspreiden van dit document is strafbaar. extra verdienen?
,Exogenously triggered (reflexive) attention
- In this paradigm a brief flash is presented in one of
the two possible target locations, this serves as an
exogenous cue for a target that might follow at that
location or the other
- The occurrence of a target at cued versus non-cued
location is random (50%/50%)
- Shortly after the exogenous cue (green shaded time
period), stimulus processing at that location is
facilitated (faster response times to cued relative to
un-cued locations)
- At longer time intervals (red shaded period),
there is decrement in performance for cued
targets
o This phenomenon is known as inhibition
of return
- After Klein (2000); data from Posner and Cohen
(1984)
Early and late selection during auditory attention
- The auditory attentional stream paradigm is a
means for studying the mechanisms of auditory
selective attention
- The asterisks indicate tones that deviate slightly
from the rest of the stimuli in a particular feature
(loudness/pitch); these tones serve as targets in
the attended channel
- The effect of auditory attention on the N1 wave at
100msec in the auditory ERP (event-related
potential) is thought to reflect a relatively early
attentional selection
- The P300 effect elicited only by detected targets in the
attended channel is thought to reflect a late-selection
process to distinct elements within the attended
channel
- Diagrams B and C are from Hillyard et al. (1983)
Gedownload door: ikarumba316 | € 912 per jaar
Dit document is auteursrechtelijk beschermd, het verspreiden van dit document is strafbaar. extra verdienen?
, Early auditory attention effects during dichotic
listening
- Even during very strongly focused auditory
spatial attention, no modulation of the
brainstem-evoked potentials (BERs) in the first
10 msecs is observed
- However, an early cortical effect is reflected as
enhanced activity from 20-50msecs for the
attended relative to the unattended tones (aka
p20-50 attention effect)
o This provides particularly strong
support for early-selection theories
- Using MEG, the p20-50 effect was indeed
localized as a local dipolar source (red arrow)
in primary auditory cortical areas on the lower
bank of the Sylvian Fissure
o This provides yet further support that
attention can affect early sensory
processing activity in the low-level
sensory cortices
- Woldorff et al. (1987)
Effects of attention on auditory feature processing as reflected by the
mismatch negativity ERP
- These overlays of the ERPs elicited by feature-deviant stimuli and
the standard (non-deviant) stimuli in the attended and he
unattended auditory streams show that the mismatch negativity
(MMN), which typically appears as increased negative-wave
activity between 150-220msecs in response to the feature-
deviating stimulus, is significantly larger in the attended
condition
- The overlay of deviance-related difference waves (deviant RP
minus non-deviant ERP for the 2 attention conditions) shows
strong effects of auditory attention on the MMN and thus on
auditory feature discrimination
- Woldorff et al. (1991)
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Dit document is auteursrechtelijk beschermd, het verspreiden van dit document is strafbaar. extra verdienen?
